This page shows what was measured, who it was measured in, and what that does not settle.
What Ciprofloxacin does in the body
Ciprofloxacin lets the cut happen and then blocks the stitching.
A bacterium copies its DNA as a closed loop, which twists tighter and tighter as the copying machinery moves along it. Two enzymes relieve that tension by cutting the DNA, letting it unwind, and stitching it back together. The bacterium is left with its own genome cut into pieces by its own enzymes, and it dies.
Why people take it. Used for certain serious bacterial infections and after exposure to anthrax.
What happened in people
For kidney infection in women, seven days cured more infections than fourteen days of an older antibiotic combination.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
Serious side effects mean it is not the first choice when safer antibiotics are suitable.
Where it acts
Bacterial cytoplasm, at the DNA-topoisomerase cleavage complex
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
Its recorded molecular formula is C17H18FN3O3, weighing 331.4.
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
A reviewer approved this sentence against this exact record and its sources.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 95 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.
Continued bacteriological and clinical cure at the 4 to 11 day post-therapy visit
✓ The study showed what it set out to show
Who was studied
Talan acute pyelonephritis trial
How many people
378
Study design
Randomised double-blind comparative
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
P = 0.004 for bacteriological cure, P = 0.002 for clinical cure
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. Drug-related adverse events occurred in 24% of ciprofloxacin patients. The class harms that later drove the boxed warning are not detectable at this sample size.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet, extended-release tablet, oral suspension, intravenous infusion, and ophthalmic and otic solutions
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
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.
Where a source records it acting
Eyes: Ophthalmic solution indicated for the treatment of corneal ulcers and conjunctivitis caused by susceptible strains (as recorded)
US prescribing information · 05b2836d-cd3d-4d7f-970c-66ec2d788667 · read 2026-08-27
Start
Ciprofloxacin
What a person takes: Oral tablet, extended-release tablet, oral suspension, intravenous infusion, and ophthalmic and otic solutions.
The measurement behind this step
Typically 250 to 750 mg twice daily by mouth, or intravenously when oral intake is not possible. Oral bioavailability of about 70% means the switch from intravenous to oral does not usually require a dose change, which is one of the practical reasons the class was so heavily used.
Getting in
Absorbed orally and distributed widely
Taken by mouth, ciprofloxacin reaches high concentrations in urine, prostate, bone and the gut wall.
╌╌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
Oral bioavailability is roughly 70%, with extensive tissue distribution and high urinary concentrations. It is a substrate and inhibitor of CYP1A2, which is why it raises theophylline and tizanidine levels. Absorption is reduced by polyvalent cations through chelation.
Crosses the bacterial envelope through porin channels
The molecule is small enough to slip through the pores in a bacterium outer coat.
╌╌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
Entry into Gram-negative bacteria is largely through OmpF porins. Reduced porin expression and increased efflux through AcrAB-TolC and MexAB-OprM are two of the three main resistance mechanisms, the third being target-site mutation.
It binds the enzyme while the enzyme is holding cut DNA
It does not stop the enzyme from cutting. It waits until the cut has been made and then locks the complex in place.
╌╌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
Ciprofloxacin intercalates at the DNA cleavage site within the gyrase or topoisomerase IV enzyme-DNA complex, bridging to the enzyme through a magnesium-water ion. Primary target is DNA gyrase in Gram-negative organisms and topoisomerase IV in many Gram-positive ones. The commonest resistance mutations are in the quinolone resistance-determining region of gyrA.
The bacterium own machinery has now cut its DNA and cannot put it back together.
╌╌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 stabilised cleavage complex is converted by ongoing replication and transcription into permanent double-strand breaks, triggering the SOS response. This mechanism is bactericidal and concentration-dependent, so efficacy tracks the ratio of peak concentration or total exposure to the minimum inhibitory concentration rather than time above it.
The bacterium dies, and human tissue takes a documented risk
The infection clears. The same class of drug is also associated with tendon, nerve and central nervous system injury in humans.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Human topoisomerase II is inhibited only at concentrations far above therapeutic ones, so the class harms are not straightforwardly explained by on-target activity in human cells. Proposed contributors include chelation of magnesium in connective tissue and effects on mitochondrial function, but the harms are established clinically and in pharmacoepidemiology rather than derived from a settled molecular mechanism.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 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.
Adults with pyelonephritis, complicated intra-abdominal or bone infection, typhoid fever, or anthrax exposure. The label directs that it be reserved in acute sinusitis, acute exacerbation of chronic bronchitis and uncomplicated cystitis for patients with no alternative.
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: “Although effective in clinical trials, ciprofloxacin is not a drug of first choice in the pediatric population due to an increased incidence of adverse reactions compared to controls.”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
On older people, the label states: “Geriatric patients are at increased risk for developing severe tendon disorders including tendon rupture when being treated with a fluoroquinolone such as ciprofloxacin.”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Prolonged experience with ciprofloxacin in pregnant women over several decades, based on available published information from case reports, case control studies and observational studies on ciprofloxacin administered during pregnancy, have not identified any drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes (see Data ) .”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary Published literature reports that ciprofloxacin is present in human milk following intravenous and oral administration.”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
On people with reduced liver function, the label states: “In preliminary studies in patients with stable chronic liver cirrhosis, no significant changes in ciprofloxacin pharmacokinetics have been observed.”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
On people with reduced kidney function, the label states: “Ciprofloxacin is eliminated primarily by renal excretion; however, the drug is also metabolized and partially cleared through the biliary system of the liver and through the intestine.”
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-30
Where the result stopped carrying
Nothing failed on efficacy. What failed was the assumption that a drug with excellent trial cure rates could be used freely for mild infections; the boxed warning now restricts three of those indications
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
Given by a clinician
❝ 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 tablet, extended-release tablet, oral suspension, intravenous infusion, and ophthalmic and otic solutions
✎ 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
Typically 250 to 750 mg twice daily by mouth, or intravenously when oral intake is not possible.
✎ 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: Oral bioavailability of about 70% means the switch from intravenous to oral does not usually require a dose change, which is one of the practical reasons the class was so heavily used.
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
The boxed warning names tendinitis and tendon rupture, peripheral neuropathy, central nervous system effects and exacerbation of myasthenia gravis, and directs that the drug be reserved in acute sinusitis, acute exacerbation of chronic bronchitis and acute uncomplicated cystitis for patients with no alternative. Observational cohorts in Taiwan and Sweden both found an increased risk of aortic aneurysm and dissection. QT prolongation, hypoglycaemia and Clostridioides difficile infection are also documented.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
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 tablet, extended-release tablet, oral suspension, intravenous infusion, and ophthalmic and otic solutions
✎ 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 recorded note compares this form with the others that are sold. It is kept below, word for word.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
The recorded note, unchanged: Oral bioavailability of about 70% means the switch from intravenous to oral does not usually require a dose change, which is one of the practical reasons the class was so heavily used.
No source is stored against this line.
What is recorded as being sold
248 products list this as an active ingredient in the United States drug directory. 229 of them contain it and nothing else.
FDA National Drug Code directory · 72189-304 · read 2026-08-29
They are sold as crystal, injection, solution, ointment, powder, solution and solution/ drops, taken auricular (otic), intravenous, ophthalmic and oral.
FDA National Drug Code directory · 72189-304 · read 2026-08-29
The regulator's established pharmacologic class for it is cytochrome p450 1a2 inhibitors [moa], fluoroquinolone antibacterial [epc] and fluoroquinolones [cs].
FDA National Drug Code directory · 72189-304 · read 2026-08-29
190 published labels name it as an active ingredient. 171 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · f406e796-17d9-4465-b8a7-00d966a4ba74 · read 2026-08-29
4 marketed supplement labels list this ingredient, classed as botanical and other combinations.
Those labels carry all other and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Ciprofloxacin Ophthalmic Solution is sterile ophthalmic solution at Ciprofloxacin Ophthalmic Solution USP 0.3% as base, recorded as rx only; fda label in effect 2022-05-02 in the United States.
US prescribing information · 05b2836d-cd3d-4d7f-970c-66ec2d788667 · read 2026-08-27
Recorded price in US: 0.07517–6.37707 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 43 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: 0.79895–3.20174 USD per one millilitre, 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 Ciprofloxacin 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 the highest cure rate in a randomised comparison identifies the correct first-line 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 switching from ciprofloxacin to another fluoroquinolone avoids the class harms, when the boxed warning is identical across the class
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 Ciprofloxacin 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.
Acute pyelonephritis: 99% bacteriological cure against 89% for co-trimoxazole
In plain words
In a randomised double-blind trial in women with kidney infection, seven days of ciprofloxacin cured more infections than fourteen days of the older combination.
What was measured
Bacteriological and clinical cure at the 4 to 11 day post-therapy visit
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Randomised, double-blind trial at 25 US outpatient centres, 378 premenopausal women enrolled and 255 evaluable. Ciprofloxacin 500 mg twice daily for 7 days versus trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days. Bacteriological cure at 4 to 11 days post-therapy was 99% (112 of 113) versus 89% (90 of 101), difference 95% CI 0.04 to 0.16, P=0.004; clinical cure 96% versus 83%, P=0.002. Escherichia coli caused more than 90% of infections and was resistant to co-trimoxazole in 18% of cases and to ciprofloxacin in none. Drug-related adverse events occurred in 24% and 33%.
Written into the record, not signed off as a reviewed claim
Uncomplicated cystitis: 77% clinical cure against 58% for amoxicillin-clavulanate
In plain words
Even against a beta-lactam the bacteria were susceptible to, ciprofloxacin cured more bladder infections, because it also cleared the reservoir in the vagina.
What was measured
Clinical cure, microbiological cure and vaginal Escherichia coli colonisation
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Randomised single-blind trial in 370 women aged 18 to 45 with acute uncomplicated cystitis. Clinical cure was 77% (124 of 162) with 3 days of ciprofloxacin 250 mg twice daily and 58% (93 of 160) with 3 days of amoxicillin-clavulanate (P<0.001), and the gap persisted among women infected with susceptible strains (77% versus 60%; P=0.004). At two weeks, vaginal Escherichia coli colonisation was 10% versus 45% (P<0.001), which the investigators identified as the mechanism of the difference.
Written into the record, not signed off as a reviewed claim
The label now tells prescribers to reserve it for three of its commonest former uses
In plain words
Ciprofloxacin was never shown to stop working. It was restricted because the harms, catalogued after approval, outweighed the benefit in mild infections.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The current US prescribing information carries a boxed warning headed "SERIOUS ADVERSE REACTIONS INCLUDING TENDINITIS, TENDON RUPTURE, PERIPHERAL NEUROPATHY, CENTRAL NERVOUS SYSTEM EFFECTS AND EXACERBATION OF MYASTHENIA GRAVIS", and directs that because these reactions can be disabling and potentially irreversible, ciprofloxacin be reserved for patients with no alternative treatment options in acute exacerbation of chronic bronchitis, acute uncomplicated cystitis and acute sinusitis. That is a benefit-risk reversal in exactly the indications where the randomised cure rates were highest.
Source
CIPRO (ciprofloxacin hydrochloride) tablets, US prescribing information, boxed warning
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
Aortic aneurysm and dissection: two independent cohorts, consistent direction
In plain words
Two large national datasets, from Taiwan and Sweden, both found more aortic aneurysms in people who had recently taken a fluoroquinolone.
What was measured
Hazard and rate ratios for hospitalisation or death from aortic aneurysm or dissection
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Lee and colleagues performed a nested case-control study in Taiwan National Health Insurance data: 1,477 patients hospitalised for aortic aneurysm or dissection matched to 147,700 controls, propensity-adjusted rate ratio 2.43 (95% CI 1.83 to 3.22) for current use and 1.48 (95% CI 1.18 to 1.86) for past use. Pasternak and colleagues used Swedish registers to compare 360,088 fluoroquinolone treatment episodes, 78% of them ciprofloxacin, with propensity-matched amoxicillin episodes: 1.2 versus 0.7 cases per 1,000 person-years within 60 days, hazard ratio 1.66 (95% CI 1.12 to 2.46), an absolute difference of 82 cases per million treatment episodes. Both are observational.
Written into the record, not signed off as a reviewed claim
Comparative efficacy in a trial is not the same as the right first choice
In plain words
Ciprofloxacin beat its comparators in both of the randomised trials on this page and is still not the recommended first choice for either condition.
What was measured
That the drug with the highest cure rate in a randomised comparison is the drug that should be prescribed first
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The efficacy trials measured cure at two to eleven weeks in a few hundred patients. The harms that changed practice — tendon rupture, peripheral neuropathy, central nervous system effects, aortic events, Clostridioides difficile infection and resistance selection — accrue at rates too low, or over horizons too long, for those trials to have detected them. A superior cure rate in a randomised comparison is therefore not sufficient evidence that a drug should be used first, and this is the general lesson rather than a fact about ciprofloxacin.
Written into the record, not signed off as a reviewed claim
Resistance is now a leading cause of death in its own right
In plain words
Fluoroquinolone-resistant E. coli is one of the seven pathogen-drug pairs that the global burden study estimated kills more than 50,000 people a year.
What was measured
Deaths attributable to fluoroquinolone-resistant Escherichia coli in 2019
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The GBD antimicrobial resistance analysis estimated 1.27 million deaths (95% UI 0.911 to 1.71 million) attributable to bacterial resistance in 2019. Fluoroquinolone-resistant Escherichia coli was named among the pathogen-drug combinations each causing between 50,000 and 100,000 attributable deaths. This is the population-level counterpart to the individual-level cure rates above, and it is measured in a different kind of study entirely.
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What is not here
7 questions this page could not answer
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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.
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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
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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.
A fluoroquinolone that traps bacterial topoisomerases mid-cut, with a 99% bacteriological cure rate against 89% for co-trimoxazole in acute pyelonephritis, and a boxed warning restricting it in three of the conditions it was most often prescribed for.
Recorded evidence blocks (11)
Q1
On the Ciprofloxacin label: indicated for what?
"Ciprofloxacin is a fluoroquinolone antibacterial indicated in adults (18 years of age and older) with the following infections caused by designated, susceptible bacteria and in pediatric patients where indicated: Skin and Skin Structure Infections ( 1.1 ) Bone and Joint Infections ( 1.2 ) Complicated Intra-Abdominal…": indications and usage on Ciprofloxacin's label. DailyMed label · 14c3bc33-201d-492e-9aee-a4d84c813a3d · 2026-08-26
Q2
194 registered trials of Ciprofloxacin — at which phases?
Registered studies posting no result
151 of 194
194 registered studies of Ciprofloxacin: 46 phase4, 39 phase1, 39 phase2, 34 phase3, 29 na, 8 na or unstated, 6 early phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01
1519 with a PubMed record
Show the evidence
phase4
46
phase1
39
phase2
39
phase3
34
na
29
na or unstated
8
8 more recorded rows
early phase1
6
completed
130
terminated
21
recruiting
17
unknown
13
withdrawn
9
active not recruiting
3
not yet recruiting
1
recorded 2026-09-01 · last checked 2026-09-04
Q3
27 of Ciprofloxacin's trials stopped: futility/efficacy, accrual/recruitment, funding/business, other?
futility/efficacy (3), accrual/recruitment (13), funding/business (1) and other (10): Ciprofloxacin's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"Permanently Closed Due to Poor Accrual"; 27 of 194 registered studies
Show the evidence
Trial
NCT00003824
terminated; "Permanently Closed Due to Poor Accrual"
NCT00062231
terminated; "low accrual"
NCT00190151
terminated; "terminated"
NCT00257699
terminated; "Inadequate recruitment to meet completion date"
NCT00431028
terminated; "Terminated"
NCT00596453
terminated; "Unable to recruit enough patients"
14 further recorded trials
NCT00760032
withdrawn; "was not possible to measure LBP levels because we cannot found the kit"
NCT00840294
terminated; "Combination of futility analysis and poor accrual"
NCT01756924
terminated; "This study has been terminated; alternative study designs are being considered. Fusidic acid remains available under an Expanded Access Protocol."
NCT01873690
terminated; "Due to the low recruitment rate and the large number lost to follow-up"
NCT02011841
withdrawn; "We failed to recruit patients"
NCT02099240
terminated; "Not enough patient enrollment and lack of staffing"
NCT02168816
terminated; "The study was stopped for feasibility (i.e., low recruitment)"
NCT02247960
terminated; "Interim analysis determined that the study should be concluded for futility."
NCT02252978
withdrawn; "No funding support"
NCT02532192
withdrawn; "Withdrawal of study support."
NCT02620007
terminated; "insufficient recruitment"
NCT02773732
terminated; "slow enrollment"
NCT03012360
terminated; "lack of inclusion pandemic, investigator reluctance, lower than expected incidence of infection"
NCT03027635
terminated; "Slow recruitment and limited funding. The treatment intervention is instituted in clinical practice as and end-stage treatment option at hospitals in Denmark"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Ciprofloxacin used Ciprofloxacin 500 mg — over how long?
Human studies of Ciprofloxacin used "Ciprofloxacin 500 mg". ClinicalTrials.gov · 2026-09-01
20 recorded entries; human; ophthalmic, oral, tablet; also "Ciprofloxacin 0.3%", "Ciprofloxacin 400mg", "Ciprofloxacin 0.3% ophthalmic solution"
oral; Antibiotic treatment (Piperacillin/Tazobactam, 4 gram x 3), followed by 8-10 days of out-hospital oral antibiotic treatment (Ciprofloxacin 500 mgx2,Flagyl 400 mgx3).
4 hours; The serum elimination half-life in subjects with normal renal function is approximately 4 hours.
tmaxpharmacokinetics
12 hours; Table 10: Steady-state Pharmacokinetic Parameters Following Multiple Oral and Intravenous Doses (Adults) Parameters 500 mg 400 mg 750 mg 400 mg every 12 hours, orally every 12 hours, intravenous every 12 hours, orally every 8 hours, intravenously AUC 0-24, ss (µg∙hr/mL) 27.4 AUC 0-12h × 2 25.4 31.6 32.9 AUC 0-8h × 3 C max (µg/mL) 2.97 4.56 3.59 4.07 Food When ciprofloxacin tablet is given…
bioavailabilitypharmacokinetics
70 %; Absorption The absolute bioavailability of ciprofloxacin when given as an oral tablet is approximately 70% with no substantial loss by first pass metabolism.
metabolismpharmacokinetics
Absorption The absolute bioavailability of ciprofloxacin when given as an oral tablet is approximately 70% with no substantial loss by first pass metabolism.
recorded 2026-08-26 · last checked 2026-09-04
Q6
Which running trial of Ciprofloxacin could settle lifespan?
NCT07202052 measures Event-free survival (EFS), reading out 2027-03-31.
3 open trials; n 900; "Role of Antibiotic Therapy or Immunoglobulin On iNfections in hAematoLogy Platform Trial (RATIONAL-PT)"
Show the evidence
Trial
NCT07202052
"Role of Antibiotic Therapy or Immunoglobulin On iNfections in hAematoLogy Platform Trial (RATIONAL-PT)"; n 900; "Event-free survival (EFS)"; 2027-03-31
NCT07202091
"Role of Antibiotic Therapy or Immunoglobulin On iNfections in hAematoLogy Immunoglobulin Stopping or Extension (Stop Ig)"; n 900; "Event-free survival (EFS)."; 2027-03-31
NCT07028424
"PANORAMIX : Optimizing 1st-line NALIRIFOX and Exploring Microbiota's Role in 2nd Line Pancreatic Cancer Treatment"; n 206; "6-month progression-free survival (PFS) rate post randomization Step 1 (R1) in Arm 1A"; 2030-12
Q7
Which 78 trials of Ciprofloxacin posted no result?
Posted no result
78 of 78 completed trials
Registrations
NCT00000641, NCT00142272, NCT04552431, NCT00669994, NCT00668044 and NCT00651586, and 72 more
Completion dates
oldest 1994-12; newest 2024-08-01
Show the evidence
Trial
NCT00000641
1994-12
NCT00142272
2002-07
NCT04552431
2003-08-31
NCT00669994
2003-10
NCT00668044
2003-11
NCT00651586
2005-04
14 further recorded trials
NCT00791505
2005-06
NCT00138411
2006-03
NCT00392275
2006-05
NCT00139230
2006-12
NCT00126698
2007-04
NCT00004216
2008-01
NCT00688272
2008-09-25
NCT00355602
2008-12
NCT00722735
2009-04
NCT01052298
2009-09
NCT00872209
2009-11
NCT00961038
2010-03
NCT00137787
2010-05
NCT00598403
2010-06
Q8
At the median, Ciprofloxacin's trials enrolled 88 people — anything larger?
Median enrolment
88
Largest enrolment
3520
Registered trials counted
193
Q9
What do 8596 spontaneous reports say about Ciprofloxacin — 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.
Ciprofloxacin appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 8596 reaction mentions were counted: drug hypersensitivity 2636; arthralgia 1041; drug interaction 1012; myalgia 686. FAERS via Open Targets · CHEMBL1202 · 2026-06-24
Show the evidence
drug hypersensitivity
2636
arthralgia
1041
drug interaction
1012
myalgia
686
tendonitis
649
acute kidney injury
602
4 more recorded rows
paraesthesia
553
tendon pain
492
tendon rupture
466
abortion spontaneous
459
recorded 2026-06-24 · last checked 2026-09-04
Q10
Which 10 reactions does Ciprofloxacin's label not list?
Ciprofloxacin is an inhibitor of human cytochrome P450 1A2 (CYP1A2) mediated metabolism.
drug_interactions
Co-administration of ciprofloxacin with other drugs primarily metabolized by CYP1A2 results in increased plasma concentrations of these drugs and could lead to clinically significant adverse events of the co-administered drug.
pharmacokinetics
Ciprofloxacin is an inhibitor of human cytochrome P450 1A2 (CYP1A2) mediated metabolism.
pharmacokinetics
Co-administration of ciprofloxacin with other drugs primarily metabolized by CYP1A2 results in increased plasma concentrations of these drugs and could lead to clinically significant adverse events of the co-administered drug [see Contraindications (4.2) , Warnings and Precautions (5.10 , 5.16) , and Drug Interactions (7) ].
clinical_pharmacology
Ciprofloxacin is an inhibitor of human cytochrome P450 1A2 (CYP1A2) mediated metabolism.
clinical_pharmacology
Co-administration of ciprofloxacin with other drugs primarily metabolized by CYP1A2 results in increased plasma concentrations of these drugs and could lead to clinically significant adverse events of the co-administered drug [see Contraindications (4.2) , Warnings and Precautions (5.10 , 5.16) , and Drug Interactions (7) ].
ChEMBL 37 — CC BY-SA 3.0 Unported · 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
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✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
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✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
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