A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Famvir Side Effects, and Drug Interactions - Famciclovir
Famvir Side Effects, and Drug Interactions - Famciclovir
SIDE EFFECTS
Immunocompetent Patients
The safety of Famvir 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.); 528 Famvir-treated patients with recurrent genital
herpes (Famvir, 125 mg b.i.d. to 500 mg t.i.d.); and 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. Table
5 lists selected adverse events.
Table 5
| |
Incidence |
| |
Herpes Zoster |
Recurrent
Genital Herpes |
Genital Herpes-Suppression |
| Event |
Famvir
(n=213)
|
Placebo
(n=146)
% |
Famvir
(n=640)
% |
Placebo
(n=225)
% |
Famvir
(n=458)
% |
Placebo
(n=63)
%
|
| Nervous System |
| Headache |
22.7 |
17.8 |
23.6 |
16.4 |
39.3 |
42.9 |
| Paresthesia |
2.6 |
0.0 |
1.3 |
0.0 |
0.9 |
0.0 |
| Migraine |
0.7 |
0.7 |
1.3 |
0.4 |
3.1 |
0.0 |
| Gastrointestinal |
| Nausea |
12.5 |
11.6 |
10.0 |
8.0 |
7.2 |
9.5 |
| Diarrhea |
7.7 |
4.8 |
4.5 |
7.6 |
9.0 |
9.5 |
| Vomiting |
4.8 |
3.4 |
1.3 |
0.9 |
3.1 |
1.6 |
| Flatulence |
1.5 |
0.7 |
1.9 |
2.2 |
4.8 |
1.6 |
| Abdominal Pain |
1.1 |
3.4 |
3.9 |
5.8 |
7.9 |
1.9 |
| Body as a Whole |
| Fatigue |
4.4 |
3.4 |
6.3 |
4.4 |
4.8 |
3.2 |
| Skin and Appendages |
| Pruritus |
3.7 |
2.7 |
0.9 |
0.0 |
2.2 |
0.0 |
| Rash |
0.4 |
0.7 |
0.6 |
0.4 |
3.3 |
1.6 |
| Reproductive Female |
| Dysmenorrhea |
0.0 |
0.7 |
2.2 |
1.3 |
7.6 |
6.3 |
* Patients may have entered into more than one clinical trial.
The following adverse events have been reported during post-approval
use of Famvir: urticaria, hallucinations 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.
Table 6 lists selected laboratory abnormalities in genital herpes suppression
trials.
Table 6
Selected Laboratory Abnormalities in Genital Herpes Suppression Studies*
| 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 (< 0.8x 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-lnfected 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 (16.0 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%).
DRUG INTERACTIONS
Concurrent use with probenecid or other drugs significantly eliminated
by active renal tubular secretion may result in increased plasma concentrations
of penciclovir.
The conversion of 6-deoxy penciclovir to penciclovir is catalyzed by
aldehyde oxidase. Interactions with other drugs metabolized by this enzyme
could potentially occur.
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