This page shows what was measured, who it was measured in, and what that does not settle.
What Cefdinir does in the body
Bacteria hold themselves together with a mesh called peptidoglycan, and they have to keep stitching new mesh as they grow.
Cefdinir jams the enzymes that make those stitches, so a dividing bacterium builds a wall it cannot close and bursts under its own internal pressure. Its particular chemistry adds a side group that resists the enzymes some bacteria use to destroy penicillins, which is why it covers organisms amoxicillin alone does not. The catch is that only about a fifth of a swallowed dose reaches the bloodstream, and iron in a supplement or a fortified cereal will bind most of what is left in the gut.
Why people take it. Ear infections in children, and chest, sinus, throat and skin infections
What happened in people
Streptococcus pyogenes eradication 94% against 70% on oral penicillin in children, with clinical cure 96 to 97% against 86%
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
Not on the WHO Model List of Essential Medicines; oral third-generation cephalosporins sit in the WHO AWaRe Watch group while amoxicillin sits in Access
Where it acts
The bacterial cell wall — the transpeptidase active site where peptidoglycan strands are cross-linked
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
17 registered substances share the start of this name, which is why a search for it can return more than one thing.
FDA substance registry · CI0FAO63WC · read 2026-08-29
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
The recorded use, written for a reader without medical training. Not signed off.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 136 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Clinical cure rate 6 to 14 days post-therapy in community-acquired pneumonia, cefdinir twice daily against amoxicillin/clavulanate 500/125 mg three times daily
✗ The study did not show it
Who was studied
European community-acquired pneumonia study, cefdinir against amoxicillin/clavulanate (cefdinir label, Clinical Studies)
How many people
201
Study design
Controlled, investigator-blind, comparator-controlled registration study
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
83 of 104 (80%) against 86 of 97 (89%); the label records the outcome as "cefdinir not equivalent to control"
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Microbiological eradication was recorded as equivalent (89% against 93%) in the same trial, so the clinical and bacteriological endpoints disagree. Haemophilus influenzae eradication was 74% against 81%.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
CMS National Average Drug Acquisition Cost (NADAC) survey — cefdinir 300 mg capsules (9 listed generic products) and oral suspension (16 listed generic produ… · a recorded source, not a stored snapshot
Eradication of Streptococcus pyogenes from the oropharynx and clinical cure 5 to 10 days post-therapy
✓ The study showed what it set out to show
Who was studied
Paediatric streptococcal pharyngitis/tonsillitis study, cefdinir 10 days against penicillin 10 days (cefdinir label, Clinical Studies)
How many people
682
Study design
Controlled comparator study in paediatric patients
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Eradication 215 of 228 (94%) once daily and 214 of 227 (94%) twice daily against 159 of 227 (70%) on penicillin four times daily; clinical cure 97% and 96% against 86%; the label records "cefdinir superior to control"
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. The endpoint is bacteriological eradication, a surrogate. The same label states cefdinir has not been studied for prevention of rheumatic fever and that only intramuscular penicillin has been demonstrated effective for that. The comparator was oral penicillin four times daily for ten days, a regimen whose real-world adherence is poor.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
CMS National Average Drug Acquisition Cost (NADAC) survey — cefdinir 300 mg capsules (9 listed generic products) and oral suspension (16 listed generic produ… · a recorded source, not a stored snapshot
Pain at 24 hours, 2 to 3 days and 4 to 7 days in children with acute otitis media, antibiotics against placebo
✗ The study did not show it
Who was studied
Venekamp RP et al., Cochrane Database Syst Rev 2023;11:CD000219 (antibiotics against placebo in acute otitis media)
How many people
3401
Study design
Systematic review and meta-analysis of 13 placebo-controlled randomised trials
Compared against
A dummy treatment
Kind of result
A number that stands in for health
What was found
Pain at 24 hours RR 0.89 (95% CI 0.78 to 1.01, high certainty) — no reduction. Pain at 2 to 3 days RR 0.71 (0.58 to 0.88), number needed to treat 20. Pain at 4 to 7 days RR 0.76 (0.50 to 1.14)
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Antibiotics increase vomiting, diarrhoea or rash (RR 1.38, 95% CI 1.16 to 1.63; number needed to harm 14, high certainty). No reduction in abnormal tympanometry at six to eight weeks or three months, and none in late recurrences. Serious complications were rare and did not differ between arms.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
CMS National Average Drug Acquisition Cost (NADAC) survey — cefdinir 300 mg capsules (9 listed generic products) and oral suspension (16 listed generic produ… · a recorded source, not a stored snapshot
What we know
RNAWiki holds 3 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Cefdinir
What a person takes: Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food.
The measurement behind this step
Absorption is poor and saturable, at an estimated 21% for a 300 mg capsule, 16% for 600 mg and 25% for the suspension, with peak plasma concentrations at 2 to 4 hours. A high-fat meal reduces suspension Cmax and AUC by 44% and 33%, which the label judges not clinically significant because the paediatric efficacy studies were conducted without regard to food. Protein binding is 60 to 70%, independent of concentration; volume of distribution is 0.35 L/kg in adults and 0.67 L/kg in children. Elimination is renal and the drug does not accumulate on once- or twice-daily dosing in normal renal function; probenecid roughly doubles exposure.
Getting in
Most of the dose never gets in
Only about a fifth of a swallowed capsule reaches the bloodstream, and the fraction gets smaller as the dose gets bigger.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Estimated bioavailability is 21% for a 300 mg capsule and 16% for 600 mg; the suspension is 25% absolute and 120% relative to capsules. Peak concentration comes at 2 to 4 hours; a 300 mg capsule gives Cmax 1.6 mcg/mL and AUC 7.05 mcg·h/mL. The drug does not accumulate on once- or twice-daily dosing with normal renal function.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
The molecule grips iron. A supplement taken at the same time removes four-fifths of what would have been absorbed, and the complex it forms turns stools red.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Sixty milligrams of elemental iron reduced the extent of absorption by 80%; a 10 mg vitamin by 31%; an aluminium or magnesium antacid reduced Cmax and AUC by about 40%. The label attributes reported reddish stools to a non-absorbable complex between cefdinir or its breakdown products and gastrointestinal iron. Iron-fortified infant formula at 2.2 mg per six ounces has no significant effect.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
It reaches the bacterium and resists its defence enzyme
Many bacteria carry an enzyme that chews up penicillins. The chemical group hanging off cefdinir gets in that enzyme’s way.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The aminothiazolyl group and the syn-hydroxyimino side chain sterically and electronically hinder hydrolysis by many beta-lactamases, which is why the label includes beta-lactamase-producing Haemophilus influenzae, Haemophilus parainfluenzae and Moraxella catarrhalis among the covered organisms. It confers nothing against pneumococcus, which resists beta-lactams by altering its penicillin-binding proteins rather than by making an enzyme.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
The beta-lactam ring mimics the end of the peptide chain those enzymes normally grab, so they bind it and stay stuck.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The four-membered beta-lactam ring is a structural mimic of the D-alanyl-D-alanine terminus of the peptidoglycan precursor. Penicillin-binding protein transpeptidases attack it and form a stable acyl-enzyme intermediate that hydrolyses very slowly, so cross-linking stops. Altered penicillin-binding proteins in penicillin-nonsusceptible pneumococcus bind cefdinir poorly, which is why those strains are excluded from the label’s indications.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
A cell that is dividing but cannot close its wall fails under its own internal pressure. Cells that are not dividing are untouched.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Bactericidal activity is time-dependent, tracking the fraction of the dosing interval during which free drug exceeds the MIC rather than the peak concentration. With 60 to 70% protein binding and a Cmax of 1.6 mcg/mL, that fraction is the pharmacodynamic quantity that determines success. Median skin blister fluid concentrations were 0.65 to 1.1 mcg/mL after a 300 mg dose.
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
The organism is eradicated — which is not the same as the outcome
It clears strep from the throat better than penicillin does. Whether it prevents rheumatic fever has never been tested, and the label says only injected penicillin has been shown to.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Paediatric S. pyogenes eradication 94% against 70% on oral penicillin, clinical cure 96 to 97% against 86%, recorded as superior. Indications section: "Cefdinir has not, however, been studied for the prevention of rheumatic fever following S. pyogenes pharyngitis/tonsillitis. Only intramuscular penicillin has been demonstrated to be effective for the prevention of rheumatic fever."
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Children with acute otitis media or streptococcal pharyngitis, and adults with sinusitis, bronchitis exacerbation, community-acquired pneumonia or uncomplicated skin infection.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and efficacy in neonates and infants less than 6 months of age have not been established.”
US prescribing information · a1f49fe1-b511-4f6b-a912-8ae8662d95a5 · read 2026-08-30
On older people, the label states: “Efficacy is comparable in geriatric patients and younger adults.”
US prescribing information · a1f49fe1-b511-4f6b-a912-8ae8662d95a5 · read 2026-08-30
On people who are pregnant, the label states: “Teratogenic Effects Cefdinir was not teratogenic in rats at oral doses up to 1000 mg/kg/day (70 times the human dose based on mg/kg/day, 11 times based on mg/m 2 /day) or in rabbits at oral doses up to 10 mg/kg/day (0.7 times the human dose based on mg/kg/day, 0.23 times based on mg/m 2 /day).”
US prescribing information · a1f49fe1-b511-4f6b-a912-8ae8662d95a5 · read 2026-08-30
On people who are breastfeeding, the label states: “Following administration of single 600 mg doses, cefdinir was not detected in human breast milk.”
US prescribing information · a1f49fe1-b511-4f6b-a912-8ae8662d95a5 · read 2026-08-30
Where the result stopped carrying
The European community-acquired pneumonia trial against amoxicillin/clavulanate, recorded on the label as "cefdinir not equivalent to control"
Bioavailability is 16 to 25% and falls with increasing dose, and is reduced by a further 80% by an ordinary iron supplement
Antibiotics in acute otitis media do not reduce pain at 24 hours, and increase adverse events with a number needed to harm of 14 against a number needed to treat of 20
Reddish stools from an iron-cefdinir complex have repeatedly triggered emergency assessment for gastrointestinal bleeding in infants
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Absorption is poor and saturable, at an estimated 21% for a 300 mg capsule, 16% for 600 mg and 25% for the suspension, with peak plasma concentrations at 2 to 4 hours.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: A high-fat meal reduces suspension Cmax and AUC by 44% and 33%, which the label judges not clinically significant because the paediatric efficacy studies were conducted without regard to food. 67 L/kg in children. Elimination is renal and the drug does not accumulate on once- or twice-daily dosing in normal renal function; probenecid roughly doubles exposure.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Most adverse events in the registration programme were mild and self-limiting, and the label states no deaths or permanent disabilities were attributed to cefdinir. Diarrhoea occurred in 15% of adults and adolescents, vaginal candidiasis in 4% of women, nausea in 3%; 3% of 5,093 patients discontinued for adverse events, primarily gastrointestinal, and 0.4% for rash. Carries the Clostridioides difficile-associated diarrhoea warning common to antibacterials, which the label notes can present over two months after the course. Contraindicated in known cephalosporin allergy, with the standard caution about cross-reactivity in penicillin-allergic patients. Absorption is reduced 80% by iron supplements and about 40% by aluminium or magnesium antacids, with a two-hour separation directed; reddish stools reflect a non-absorbable cefdinir-iron complex rather than bleeding.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Where this came from
Cefdinir capsules and oral suspension United States prescribing information — Indications and Usage, Clinical Pharmacology, Drug Interactions, Adverse Events… · a recorded source, not a stored snapshot
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Oral capsule at 300 mg and oral suspension at 125 and 250 mg per 5 mL — taken once or twice daily, with or without food
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
A high-fat meal reduces suspension Cmax and AUC by 44% and 33%, which the label judges not clinically significant because the paediatric efficacy studies were conducted without regard to food. 67 L/kg in children. Elimination is renal and the drug does not accumulate on once- or twice-daily dosing in normal renal function; probenecid roughly doubles exposure.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
84 products list this as an active ingredient in the United States drug directory. 84 of them contain it and nothing else.
FDA National Drug Code directory · 72189-423 · read 2026-08-29
They are sold as capsule, powder and powder, for suspension, taken oral.
FDA National Drug Code directory · 72189-423 · read 2026-08-29
The regulator's established pharmacologic class for it is cephalosporin antibacterial [epc] and cephalosporins [cs].
FDA National Drug Code directory · 72189-423 · read 2026-08-29
69 published labels name it as an active ingredient. 69 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 2da6eb80-63b0-4377-8d7b-865733ebbab1 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 2da6eb80-63b0-4377-8d7b-865733ebbab1 · read 2026-08-29
Cefdinir is oral at HOW SUPPLIED Cefdinir for oral suspension, USP is a white to off-white powder formulation that, when reconstituted as directed, contains either 125 mg cefdinir/5 mL or 250 mg cefdinir/5 mL., recorded as fda label in effect 2023-02-01 in the United States.
US prescribing information · a1f49fe1-b511-4f6b-a912-8ae8662d95a5 · read 2026-08-30
Recorded price in US: 0.10626–0.11949 USD per one millilitre, across 16 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Recorded price in US: 0.4593 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 9 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Cefdinir studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That a third-generation cephalosporin covers resistant pneumococcus better than amoxicillin — every pneumococcal indication on the label reads "penicillin-susceptible strains only"
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That superior throat eradication means superior prevention of rheumatic fever, which the label states has not been studied for this drug
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That treating acute otitis media with an antibiotic prevents complications; the pooled trials found serious complications rare and no different from placebo
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That a bacteriological endpoint and a clinical endpoint agree — in the label’s own pneumonia trial, eradication was equivalent and clinical cure was not
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Cefdinir are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
Every respiratory indication is limited to penicillin-susceptible pneumococcus
In plain words
Cefdinir is reached for as a stronger alternative to penicillin. Its label licenses it against pneumococcus only where penicillin still works — which is the situation in which the cheaper, narrower drug would have worked too.
What was measured
That a third-generation oral cephalosporin covers resistant pneumococcus better than high-dose amoxicillin — the label restricts its pneumococcal indications to penicillin-susceptible strains only
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The Indications and Usage section attaches the same parenthesis to Streptococcus pneumoniae in community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute maxillary sinusitis and paediatric acute bacterial otitis media: "(penicillin-susceptible strains only)". The pharmacological reason is that reduced penicillin susceptibility in pneumococcus is caused by mosaic alterations in the penicillin-binding proteins, and those same altered proteins bind cefdinir less well; beta-lactamase stability, which is what cefdinir’s aminothiazolyl-oxime chemistry buys, is irrelevant because pneumococcus does not make beta-lactamase. Where cefdinir genuinely adds coverage is against beta-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis, and the label says so by including those with the qualifier "(including β-lactamase producing strains)". The inference the label blocks is the common one: that a later-generation cephalosporin is a stronger version of amoxicillin against the organism that matters most in these infections.
Source
Cefdinir United States prescribing information, Indications and Usage (Omnicef, NDA 050739 / 050749)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
It lost a head-to-head trial, and the result is printed on its own label
In plain words
In a European pneumonia trial against amoxicillin-clavulanate, cefdinir cured 80% against 89%. The label reports the outcome in three words: "cefdinir not equivalent to control".
What was measured
Clinical cure rate against amoxicillin-clavulanate in community-acquired pneumonia, with the label’s own equivalence determination
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Clinical Studies section reports two community-acquired pneumonia trials. In a United States double-blind trial against cefaclor, clinical cure was 150 of 187 (80%) with cefdinir twice daily against 147 of 186 (79%) with cefaclor three times daily, and the label records "cefdinir equivalent to control". In a second, investigator-blind trial conducted primarily in Europe against amoxicillin-clavulanate 500/125 mg three times daily, clinical cure was 83 of 104 (80%) against 86 of 97 (89%) and the label records "cefdinir not equivalent to control" — a documented non-inferiority failure against the comparator most likely to be used instead of it. Microbiological eradication was recorded as equivalent (89% against 93%), so the two endpoints disagree in the same trial. Pneumococcal eradication was near-identical (95% against 98%); Haemophilus influenzae eradication was 74% against 81%. A label that publishes a trial its own drug lost is doing something unusual and correct, and it is a result almost nobody prescribing the drug has read.
Source
Cefdinir United States prescribing information, Clinical Studies — Community-Acquired Bacterial Pneumonia
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
It clears strep throat better than penicillin — on a surrogate
In plain words
In children, cefdinir eradicated the streptococcus from the throat in 94% against penicillin’s 70%. The same label then says cefdinir has never been studied for preventing rheumatic fever, and that only injected penicillin has been shown to do that.
What was measured
Bacteriological eradication of Streptococcus pyogenes and clinical cure against oral penicillin, with rheumatic fever prevention unstudied
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Four controlled United States studies compared cefdinir with ten days of penicillin. In adults and adolescents, eradication of S. pyogenes was 192 of 210 (91%) once daily and 199 of 217 (92%) twice daily against 181 of 217 (83%) on penicillin four times daily, with clinical cure 95% and 96% against 89% — recorded as "cefdinir superior to control". In children the gap was larger: eradication 215 of 228 (94%) and 214 of 227 (94%) against 159 of 227 (70%), clinical cure 97% and 96% against 86%, again superior. Then the Indications section adds, twice: "Cefdinir is effective in the eradication of S. pyogenes from the oropharynx. Cefdinir has not, however, been studied for the prevention of rheumatic fever following S. pyogenes pharyngitis/tonsillitis. Only intramuscular penicillin has been demonstrated to be effective for the prevention of rheumatic fever." This is a textbook surrogate-versus-outcome separation stated inside a single regulatory document: the drug is measurably better at the laboratory endpoint and has no evidence at all on the clinical endpoint that is the reason for treating the infection. Note also what the comparator was — penicillin four times daily for ten days — and what adherence to that regimen looks like outside a trial.
Source
Cefdinir United States prescribing information, Indications and Usage and Clinical Studies — Streptococcal Pharyngitis/Tonsillitis
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
contested
Review state
Written into the record, not signed off as a reviewed claim
One fifth of the dose gets in, and a vitamin removes most of that
In plain words
Absolute bioavailability is 16 to 25%, and it falls as the dose rises. An iron supplement taken at the same time cuts absorption by a further 80%.
What was measured
Absolute oral bioavailability, dose-proportionality, and reduction in absorption with iron, antacid and food
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The label states that plasma concentrations increase less than dose-proportionally from 300 mg to 600 mg, that estimated bioavailability of capsules is 21% at 300 mg and 16% at 600 mg, and that estimated absolute bioavailability of the suspension is 25%. Concomitant iron at 60 mg of elemental iron reduced the extent of absorption by 80%, and a 10 mg vitamin by 31%; an aluminium or magnesium antacid reduced Cmax and AUC by about 40%, with a two-hour separation directed in each case. A high-fat meal reduces suspension Cmax and AUC by 44% and 33%. The consequence is a narrow and fragile exposure: peak plasma concentration after a 300 mg capsule is 1.6 mcg/mL with 60 to 70% protein binding, and beta-lactam efficacy depends on how long free drug stays above the organism’s MIC. There is not much headroom in that calculation, and an interaction that removes four-fifths of the absorbed dose does not announce itself — it presents as a treatment failure.
Source
Cefdinir United States prescribing information, Clinical Pharmacology — Absorption, Effect of Food, and Drug Interactions
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
caution
Review state
Written into the record, not signed off as a reviewed claim
The commonest reason to prescribe it is an infection that mostly resolves anyway
In plain words
Pooled randomised trials in 3,401 children found antibiotics do not reduce ear pain at 24 hours, help about one child in twenty at two to three days, and cause vomiting, diarrhoea or rash in about one in fourteen.
What was measured
Pain at 24 hours, 2 to 3 days and 4 to 7 days, adverse events, and serious complications with antibiotics against placebo in acute otitis media
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A Cochrane review of 13 placebo-controlled trials in 3,401 children from high-income countries, assessed at generally low risk of bias, found antibiotics do not reduce pain at 24 hours (RR 0.89, 95% CI 0.78 to 1.01, high-certainty evidence) or at four to seven days (RR 0.76, 0.50 to 1.14), but result in almost a third fewer children having pain at two to three days (RR 0.71, 0.58 to 0.88; number needed to treat 20, high certainty). They increase vomiting, diarrhoea or rash (RR 1.38, 1.16 to 1.63; number needed to harm 14, high certainty). They reduce abnormal tympanometry at two to four weeks (NNT 11) but not at six to eight weeks or three months, reduce tympanic perforation (NNT 33), halve contralateral otitis (NNT 11), and do not reduce late recurrences. Serious complications were rare and did not differ between antibiotic and placebo. The 2013 American Academy of Pediatrics guideline responded by making observation with close follow-up an explicit option for many children and naming high-dose amoxicillin first where an antibiotic is used. Cefdinir sits below both of those in the guideline sequence, and above both in prescribing volume.
Written into the record, not signed off as a reviewed claim
Diarrhoea in 15% of adults, and it is the reason people stop
In plain words
Across nearly four thousand adults in the United States trials, fifteen per cent had diarrhoea. It was the commonest reason for stopping the drug.
What was measured
Incidence of adverse events and discontinuation in 5,093 adult and adolescent trial patients
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In the United States capsule trials with 3,841 cefdinir-treated adults and adolescents, diarrhoea occurred in 15%, vaginal candidiasis in 4% of women, nausea in 3%, headache in 2% and abdominal pain in 1%. One hundred and forty-seven of 5,093 patients (3%) discontinued for adverse events attributed to the drug, primarily gastrointestinal, usually diarrhoea or nausea, and 19 of 5,093 (0.4%) for rash. The label states most adverse events were mild and self-limiting and that no deaths or permanent disabilities were attributed to cefdinir. This is a favourable safety profile in absolute terms; it is worth setting beside the Cochrane number needed to harm of 14 for vomiting, diarrhoea or rash in the paediatric otitis media population, because in a condition where the number needed to treat for pain relief is 20, an adverse event rate of this size is not a footnote to the benefit calculation — it is most of it.
Source
Cefdinir United States prescribing information, Adverse Events — Clinical Trials, Cefdinir Capsules (Adult and Adolescent Patients)
Role in the trial
Not matched to a registered study
Identity check
no open identity hold
Audit mark
verified
Review state
Written into the record, not signed off as a reviewed claim
How many documents were read
69 documents were read for this substance.
RNAWiki source record
69 of them state the same bioavailability, and they agree.
RNAWiki source record
69 of them state the same volumeOfDistribution, and they agree.
RNAWiki source record
Checks this page had to pass
✓ Passed
Identity resolved
no open identity hold
✓ Passed
No unresolved merge across substance families
no quarantine open
✓ Passed
Every public sentence names a source
The opening statement carries the origin: Written into the record, not signed off.
✗ Not passed
Trial roles classified for highlighted evidence
No registered study is classified as testing this substance.
✓ Passed
No internal keys in reader text
enforced by the copy-contract test over the rendered page
✗ Not passed
Safety mode resolved
No register row and no identity class settled the question.
✓ Passed
Canonical metadata present
slug and display name present
What is missing or unclear◇Read from sources, not yet reviewed
How this medicine reached us
Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.
What the approval register records
14 approved applications cover products containing this substance. The earliest was NDA050739, approved 19971204 to ABBVIE.
This order is fixed in code and does not count clicks or time on the page.
What is not here
7 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
An oral third-generation cephalosporin whose label limits every respiratory indication to penicillin-susceptible Streptococcus pneumoniae, whose absolute bioavailability is 16 to 25%, and which its own Clinical Studies section records as "not equivalent to control" against amoxicillin-clavulanate in a European pneumonia trial (80% against 89% clinical cure) — while beating penicillin on streptococcal eradication in children, 94% against 70%, on a surrogate the same label says has never been linked to rheumatic fever prevention for this drug.
Recorded evidence blocks (8)
Q1
On the Cefdinir label: indicated for what?
"To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefdinir for oral suspension, USP and other antibacterial drugs, cefdinir for oral suspension, USP should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When…": indications and usage on Cefdinir's label. DailyMed label · 0eeac6df-bad7-413e-8b41-0660f3a99373 · 2026-08-20
Q2
22 registered trials of Cefdinir — at which phases?
Registered studies posting no result
19 of 22
22 registered studies of Cefdinir: 12 phase4, 6 phase1, 1 early phase1, 1 na, 1 na or unstated, 1 phase2, 1 phase3. CLINICALTRIALS_SNAPSHOT · 2026-09-01
NCT00882154, NCT00882700, NCT00882570, NCT00883883, NCT01000298 and NCT00147914
Completion dates
oldest 2005-04; newest 2017-02-18
Show the evidence
Trial
NCT00882154
2005-04
NCT00882700
2005-04
NCT00882570
2005-05
NCT00883883
2005-05
NCT01000298
2011-05
NCT00147914
2017-02-18
Q6
At the median, Cefdinir's trials enrolled 155.5 people — anything larger?
Median enrolment
155.5
Largest enrolment
5000
Registered trials counted
22
Q7
What do 496 spontaneous reports say about Cefdinir — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Cefdinir appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 496 reaction mentions were counted: drug hypersensitivity 137; faeces discoloured 88; rash 74; urticaria 47. FAERS via Open Targets · CHEMBL927 · 2026-06-24
Show the evidence
drug hypersensitivity
137
faeces discoloured
88
rash
74
urticaria
47
clostridial infection
34
stevens-johnson syndrome
32
4 more recorded rows
haematochezia
27
clostridium difficile colitis
22
liver disorder
18
serum sickness
17
recorded 2026-06-24 · last checked 2026-09-04
Q8
Which 10 reactions does Cefdinir's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.