Famvir Side Effects
Generic Name: Famciclovir
Please note - some side effects for Famvir may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).
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For the consumer For the professional
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Side Effects of Famvir - for the consumer
Famvir
All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Famvir:
Seek medical attention right away if any of these SEVERE side effects occur when using Famvir:Diarrhea; gas; headache; tiredness; vomiting.
TopSevere allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); change in the amount of urine produced; confusion; delirium; disorientation; hallucinations; red, swollen, blistered, or peeling skin.
For the professional
Famvir
Immunocompetent Patients
The safety of Famvir® (famciclovir) has been evaluated in clinical studies involving 816 Famvir-treated patients with herpes zoster (Famvir, 250 mg t.i.d. to 750 mg t.i.d.); 163 Famvir-treated patients with recurrent genital herpes (Famvir, 1000 mg b.i.d.); 1,197 patients with recurrent genital herpes treated with Famvir as suppressive therapy (125 mg q.d. to 250 mg t.i.d.) of which 570 patients received Famvir (open-labeled and/or double-blind) for at least 10 months; and 447 Famvir-treated patients with herpes labialis (Famvir, 1500 mg once or 750 mg b.i.d.). Table 5 lists selected adverse events.
| Incidence | ||||||||
| Herpes Zoster† |
Recurrent Genital Herpes‡ |
Genital Herpes- Suppression§ |
Herpes Labialis‡ | |||||
| Event | Famvir® | Placebo | Famvir ® | Placebo | Famvir® | Placebo | Famvir® | Placebo |
| 500 mg | 1 gram | 250 mg | 1500 mg | |||||
| t.i.d* | b.i.d* | b.i.d* | single dose* | |||||
| (n=273) | (n=146) | (n=163) | (n=166) | (n=458) | (n=63) | (n=227) | (n=254) | |
| % | % | % | % | % | % | % | % | |
| Nervous System | ||||||||
| Headache | 22.7 | 17.8 | 13.5 | 5.4 | 39.3 | 42.9 | 9.7 | 6.7 |
| Paresthesia | 2.6 | 0.0 | 0.0 | 0.0 | 0.9 | 0.0 | 0.0 | 0.0 |
| Migraine | 0.7 | 0.7 | 0.6 | 0.6 | 3.1 | 0.0 | 0.0 | 0.0 |
| Gastrointestinal | ||||||||
| Nausea | 12.5 | 11.6 | 2.5 | 3.6 | 7.2 | 9.5 | 2.2 | 3.9 |
| Diarrhea | 7.7 | 4.8 | 4.9 | 1.2 | 9.0 | 9.5 | 1.8 | 0.8 |
| Vomiting | 4.8 | 3.4 | 1.2 | 0.6 | 3.1 | 1.6 | 0.0 | 0.0 |
| Flatulence | 1.5 | 0.7 | 0.6 | 0.0 | 4.8 | 1.6 | 0.0 | 0.0 |
| Abdominal Pain | 1.1 | 3.4 | 0.0 | 1.2 | 7.9 | 7.9 | 0.0 | 0.4 |
| Body as a Whole | ||||||||
| Fatigue | 4.4 | 3.4 | 0.6 | 0.0 | 4.8 | 3.2 | 1.3 | 0.4 |
| Skin and Appendages | ||||||||
| Pruritus | 3.7 | 2.7 | 0.0 | 0.6 | 2.2 | 0.0 | 0.0 | 0.0 |
| Rash | 0.4 | 0.7 | 0.0 | 0.0 | 3.3 | 1.6 | 0.0 | 0.0 |
| Reproductive Female | ||||||||
| Dysmenorrhea | 0.0 | 0.7 | 1.8 | 0.6 | 7.6 | 6.3 | 0.9 | 0.0 |
*Patients may have entered into more than one clinical trial.
†7 days of treatment
‡1 day of treatment
§daily treatment
Table 6 lists selected laboratory abnormalities in genital herpes suppression trials.
| Parameter |
Famvir® (n = 660)† % |
Placebo (n = 210)† % |
| Anemia (<0.8 x NRL) | 0.1 | 0.0 |
| Leukopenia (<0.75 x NRL) | 1.3 | 0.9 |
| Neutropenia (<0.8 x NRL) | 3.2 | 1.5 |
| AST (SGOT) (>2 x NRH) | 2.3 | 1.2 |
| ALT (SGPT) (>2 x NRH) | 3.2 | 1.5 |
| Total Bilirubin (>1.5 x NRH) | 1.9 | 1.2 |
| Serum Creatinine (>1.5 x NRH) | 0.2 | 0.3 |
| Amylase (>1.5 x NRH) | 1.5 | 1.9 |
| Lipase (>1.5 x NRH) | 4.9 | 4.7 |
*Percentage of patients with laboratory abnormalities that were increased or decreased from baseline and were outside of specified ranges.
†n values represent the minimum number of patients assessed for each laboratory parameter.
NRH = Normal Range High.
NRL = Normal Range Low.
HIV-Infected Patients
In HIV-infected patients, the most frequently reported adverse events for famciclovir (500 mg twice daily; n=150) and acyclovir (400 mg, 5x/day; n=143), respectively, were headache (16.7% vs. 15.4%), nausea (10.7% vs. 12.6%), diarrhea (6.7% vs. 10.5%), vomiting (4.7% vs. 3.5%), fatigue (4.0% vs. 2.1%), and abdominal pain (3.3% vs. 5.6%).
Post Marketing Experience
The following adverse events have been reported during post-approval use of Famvir: urticaria, serious skin reactions (e.g. erythema multiforme,Stevens-Johnson syndrome, toxic epidermal necrolysis), cholestatic jaundice, abnormal liver function tests, thrombocytopenia, hallucinations, dizziness, somnolence and confusion (including delirium, disorientation, confusional state, occurring predominantly in the elderly). Because these adverse events are reported voluntarily from a population of unknown size, estimates of frequency cannot be made.
TopMore resources:
Famvir - Includes detailed dosage instructions.
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