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Famciclovir

  • Prescription medicine
  • Prescription only
  • Identity checked
  • Sources last checked 2026-09-04

This page shows what was measured, who it was measured in, and what that does not settle.

What Famciclovir does in the body

Recurrent episodes of orolabial or genital herpes in HIV-infected patients Black and African American patients with recurrent genital herpes

4 ) ] .

What happened in people

RNAWiki has not yet published a reviewed conclusion for this use.

A fixed RNAWiki sentence

Where this came from

Wording RNAWiki always uses, not a finding about this substance.

No reviewed claim names a result for any goal on this record.

No source is stored against this line.

The limit that matters most

Not recorded.

Where it acts
Not recorded.
Kind of result
No result is published, so no kind of result applies yet
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.

What the registries record it as

  • The substance registry classes this as chemical.

    FDA substance registry · QIC03ANI02 · read 2026-08-29

Where each sentence above came from

No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.

Shown as the opening line on this page.

No statement of the main limit is recorded.

The four opening statements run to 33 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.

Biomarker

A biomarker is a number from a test that stands in for something about health.

A picture of it, and where the picture fails

A biomarker is like a fuel gauge.

Where that stops being true. A gauge is wired to the tank. Many biomarkers are only loosely tied to health.

What people get wrong. A better number is read as a better life. Several medicines improved a number and helped nobody.

A measurable indicator used as a substitute for a clinical outcome of interest.

Placebo

A placebo is a dummy treatment given so the real one can be compared with it.

A picture of it, and where the picture fails

A placebo is like a blank control in an experiment.

Where that stops being true. A blank does nothing. People given a placebo often do get better.

What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.

An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.

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.

What happened in peopleRead 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.

Estimated probability being not lesion-free(i.e. not healed) 5.5 elapsed days (132 hours) after patient self-initiation therapy.

The study did not show it

Who was studied
NCT00171990
How many people
1461
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Investigator-assessed Time to Healing of All Non-aborted Genital Herpes Lesions

The study did not show it

Who was studied
NCT00306787
How many people
1179
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

VAS scores at different follow-up time points.

The study did not show it

Who was studied
NCT07344246
How many people
954
Study design
Not applicable
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Investigator Assessed Time to Healing of All Non-aborted Genital Herpes Lesions

The study did not show it

Who was studied
NCT00477334
How many people
463
Study design
Phase 4
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

For efficacy evaluation, a visual analogue scale (VAS) will be used to detect the improvement of symptoms

The study did not show it

Who was studied
NCT01327144
How many people
177
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Efficacy Will be Evaluated by the Proportion of Subjects With Non Herpes Manifestation

The study did not show it

Who was studied
NCT01281007
How many people
150
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
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. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot
What we know
RNAWiki holds 6 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 is missing or unclearRead 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.

  • Famciclovir tablets, a prodrug of penciclovir, are a deoxynucleoside analog DNA polymerase inhibitor indicated for: Immunocompetent Adult Patients ( 1.1 ) Herpes labialis (cold sores) Treatment of recurrent episodes Genital herpes Treatment of recurrent episodes Suppressive therapy of recurrent episodes Herpes zoster (shingles) Human Immunodeficiency Virus (HIV) -Infected Adult Patients ( 1.2 ) Treatment of…

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: “The efficacy of famciclovir has not been established in pediatric patients.”

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-30

  • On older people, the label states: “Of 816 patients with herpes zoster in clinical studies who were treated with famciclovir, 248 (30.4%) were greater than or equal to 65 years of age and 103 (13%) were greater than or equal to 75 years of age.”

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-30

  • On people who are pregnant, the label states: “Risk Summary Available data from pharmacovigilance reports with famciclovir use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.”

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-30

  • On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of famciclovir (prodrug) or penciclovir (active drug) in human milk, the effects on the breastfed infant, or the effects on milk production.”

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-30

Where the result stopped carrying

  • 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 takeRead 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 takeRead 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

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

Sold as tablet, tablet, film coated, given by the oral route.

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 and what that means for what is in the pack.

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 takeNothing found in the sources checked

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.

Nothing found in the sources checked

No harm is recorded against this substance in the sources RNAWiki checked. Finding nothing is not the same as showing there is nothing.

The sources listed were searched and held nothing. That is not the same as nothing existing.

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 unclearRead 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

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

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

Nothing further is recorded about which forms are sold.

No source is stored against this line.

What is recorded as being sold

  • 40 products list this as an active ingredient in the United States drug directory. 40 of them contain it and nothing else.

    FDA National Drug Code directory · 65862-467 · read 2026-08-29

  • They are sold as powder and tablet, film coated, taken oral.

    FDA National Drug Code directory · 65862-467 · read 2026-08-29

  • The regulator's established pharmacologic class for it is dna polymerase inhibitors [moa], herpesvirus nucleoside analog dna polymerase inhibitor [epc] and nucleoside analog [ext].

    FDA National Drug Code directory · 65862-467 · read 2026-08-29

  • 12 published labels name it as an active ingredient. 12 of them describe this substance alone, which is where its own label text on this page comes from.

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-29

  • Those labels are classed as human prescription drug.

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-29

  • Famciclovir is oral at 3 DOSAGE FORMS AND STRENGTHS Famciclovir Tablets are available in three strengths: 125 mg: White, round, film-coated, unscored tablets, debossed with “8117” on one side and “93” on the other side 250 mg: White, round, f…, recorded as fda label in effect 2026-01-14 in the United States.

    US prescribing information · c2b21ad5-fa83-1fb6-e053-2a95a90a3d0f · read 2026-08-30

  • Recorded price in US: 0.21389–0.79122 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 18 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 takeRead 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 Famciclovir 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 unclearRead 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 Famciclovir 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 peopleRead 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.

How many documents were read

  • 12 documents were read for this substance.

    RNAWiki source record

  • 12 of them state the same bioavailability, and they agree.

    RNAWiki source record

  • 10 of them state the same tMax, and they agree.

    RNAWiki source record

  • 12 of them state the same volumeOfDistribution, and they agree.

    RNAWiki source record

Where else this substance is registered

FDA substance identifier (UNII)
QIC03ANI02
RxNorm concept
198382

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 unclearRead 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

  • 9 approved applications cover products containing this substance. The earliest was NDA020363, approved 19940629 to NOVARTIS.

    Drugs@FDA application register · NDA020363 · read 2026-08-29

  • Marketing status on the register: discontinued and prescription.

    Drugs@FDA application register · NDA020363 · read 2026-08-29

  • The earliest marketing start date recorded for a listed product is 19960426.

    FDA National Drug Code directory · 65862-467 · read 2026-08-29

What is missing or unclearRead from sources, not yet reviewed

What to learn next

Ordered by what would most change how you read this page, starting with what is easiest to misunderstand.

This order is fixed in code and does not count clicks or time on the page.

What is not here

9 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.
  • The path through the body — 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.
  • Claims that go past the evidence — 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.

Recorded evidence blocks (9)

On the Famciclovir label: indicated for what?


"1 INDICATIONS & USAGE Famciclovir tablet, a prodrug of penciclovir, is a deoxynucleoside analog DNA polymerase inhibitor indicated for: Immunocompetent Adult Patients ( 1.1 ) • Herpes labialis (cold sores) o Treatment of recurrent episodes • Genital herpes o Treatment of recurrent episodes o Suppressive therapy of…": indications and usage on Famciclovir's label. DailyMed label · 5723f50e-b0fa-65f0-e063-6294a90a350f · 2026-07-21

20 registered trials of Famciclovir — at which phases?


Registered studies posting no result
11 of 20

20 registered studies of Famciclovir: 8 phase3, 5 phase4, 3 na, 3 phase2, 2 phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01

96 with a PubMed record

Show the evidence
  • phase3
    8
  • phase4
    5
  • na
    3
  • phase2
    3
  • phase1
    2
  • completed
    16
3 more recorded rows
  • unknown
    2
  • recruiting
    1
  • terminated
    1

recorded 2026-09-01 · last checked 2026-09-04

Why did Famciclovir's trial NCT01526408 stop?


1 recorded trial of Famciclovir stopped. CLINICALTRIALS_SNAPSHOT · 2026-09-01

"HRI no longer conducting research."; 1 of 20 registered studies

Show the evidence
  • Trial NCT01526408
    terminated; "HRI no longer conducting research."

recorded 2026-09-01 · last checked 2026-09-04

Human studies of Famciclovir used Famciclovir 500 mg Tablets — over how long?


Human studies of Famciclovir used "Famciclovir 500 mg Tablets". ClinicalTrials.gov · 2026-09-01

2 recorded entries; human; also "Famvir® 500 mg Tablets"

Show the evidence

human

  • NCT00834431
    Famciclovir 500 mg Tablets
  • NCT00834431
    Famvir® 500 mg Tablets

recorded 2026-09-01 · last checked 2026-09-04

Famciclovir's half-life is 2.0 ± 0.3 hours — which schedules were studied?


2.0 ± 0.3 hours, the half-life Famciclovir's label states: "The plasma elimination half-life of penciclovir was 2.0 ± 0.3 hours after intravenous administration of penciclovir to 48 healthy male volunteers and 2.3 ± 0.4 hours after oral administration of 500 mg famciclovir to 124 healthy male volunteers." DailyMed label · 5723f50e-b0fa-65f0-e063-6294a90a350f · 2026-07-21

tmax 0.7±0.2 hours; bioavailability 77 ± 8 %.

Show the evidence
  • half life pharmacokinetics
    2.0 ± 0.3 hours; The plasma elimination half-life of penciclovir was 2.0 ± 0.3 hours after intravenous administration of penciclovir to 48 healthy male volunteers and 2.3 ± 0.4 hours after oral administration of 500 mg famciclovir to 124 healthy male volunteers.
  • tmax pharmacokinetics
    0.7±0.2 hours; Following oral single-dose administration of 500 mg famciclovir to 7 patients with herpes zoster, the AUC (mean ± SD), C max , and t max were 12.1±1.7 mcg hr/mL, 4.0±0.7 mcg/mL, and 0.7±0.2 hours, respectively.
  • bioavailability pharmacokinetics
    77 ± 8 %; Pharmacokinetics in adults: Absorption and Bioavailability: The absolute bioavailability of penciclovir is 77 ± 8% as determined following the administration of a 500 mg famciclovir oral dose and a 400 mg penciclovir intravenous dose to 12 healthy male subjects.
  • metabolism pharmacokinetics
    Following oral administration famciclovir undergoes rapid and extensive metabolism to penciclovir and little or no famciclovir is detected in plasma or urine.

recorded 2026-07-21 · last checked 2026-09-04

Which 8 trials of Famciclovir posted no result?


Posted no result
8 of 8 completed trials
Registrations
NCT00219310, NCT00129818, NCT00171990, NCT00098046, NCT00248144 and NCT01321502, and 2 more
Completion dates
oldest 2005-06; newest 2017-07
Show the evidence

Trial

  • NCT00219310
    2005-06
  • NCT00129818
    2005-10
  • NCT00171990
    2006-02
  • NCT00098046
    2007-07
  • NCT00248144
    2007-07
  • NCT01321502
    2007-07
2 further recorded trials
  • NCT01321515
    2007-07
  • NCT01327144
    2017-07

At the median, Famciclovir's trials enrolled 74 people — anything larger?


Median enrolment
74
Largest enrolment
1461
Registered trials counted
17

What do 137 spontaneous reports say about Famciclovir — 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.

Famciclovir appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 137 reaction mentions were counted: rash 27; confusional state 16; haemoglobin decreased 14; angioedema 14. FAERS via Open Targets · CHEMBL880 · 2026-06-24

Show the evidence
  • rash
    27
  • confusional state
    16
  • haemoglobin decreased
    14
  • angioedema
    14
  • herpes zoster
    13
  • chest discomfort
    13
4 more recorded rows
  • vision blurred
    12
  • urinary incontinence
    10
  • acute myeloid leukaemia
    9
  • heart rate increased
    9

recorded 2026-06-24 · last checked 2026-09-04

Which 10 reactions does Famciclovir's label not list?


acute myeloid leukaemia, angioedema and chest discomfort and 7 more reported for Famciclovir, absent from its label. FAERS via Open Targets · CHEMBL880 · 2026-06-24

2 label terms; 10 reported and unlisted; 5723f50e-b0fa-65f0-e063-6294a90a350f

Show the evidence
  • acute myeloid leukaemia
    count not stated
  • angioedema
    count not stated
  • chest discomfort
    count not stated
  • confusional state
    count not stated
  • haemoglobin decreased
    count not stated
  • heart rate increased
    count not stated
4 more recorded rows
  • herpes zoster
    count not stated
  • rash
    count not stated
  • urinary incontinence
    count not stated
  • vision blurred
    count not stated

recorded 2026-06-24 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL880
PubChem CID
3324
CAS number
104227-87-4
RxCUI
68099
InChIKey
GGXKWVWZWMLJEH-UHFFFAOYSA-N
Development code
BRL-42810, NSC-758921
Trade name
Famvir
Also called
1,3-PROPANEDIOL, 2-(2-(2-AMINO-9H-PURIN-9-YL)ETHYL)-, DIACETATE (ESTER), 2-[2-(2-Amino-9H-purin-9-yl)ethyl]-1,3-propanediol diacetate (ester), FAMCICLOVIR [JAN], FAMCICLOVIR [MART.], FAMCICLOVIR [MI], FAMCICLOVIR [ORANGE BOOK], FAMCICLOVIR [USAN], FAMCICLOVIR [USP MONOGRAPH], FAMCICLOVIR [USP-RS], FAMCICLOVIR [VANDF]
Sources (6)

Sources

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

How these records are assembled · Which registers were checked

Index-quality checks
  • identity passed: no open identity hold
  • 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.