Famvir

>10%

Headache (23%)

Nausea (13%)

1-10%

Diarrhea (2-9%)

Abdominal pain (8%)

Dysmenorrhea (<8%)

Vomiting (1-5%)

Flatulence (5%)

Pruritus (4%)

Rash (3%)

Paresthesia (3%)

Neutropenia (3%)

Increased transaminases (2-3%)

Increased bilirubin (2%)

Fatigue (1%)

<1%

Arthralgia

Confusion

Dizziness

Erythema multiforme

Hallucinations

Jaundice

Rigors

Thrombocytopenia

Upper respiratory tract infection

Postmarketing Reports

Blood and lymphatic system disorders: Thrombocytopenia

Immune system disorders anaphylactic shock and anaphylactic reaction under

Hepatobiliary disorders: Abnormal liver function tests, cholestatic jaundice

Nervous system disorders: Dizziness, somnolence, seizures

Psychiatric disorders: Confusion (including delirium, disorientation, and confusional state occurring predominantly in the elderly), hallucinations

Skin and subcutaneous tissue disorders: Urticaria, Stevens-Johnson syndrome, toxic epidermal necrolysis, angioedema (eg, face, eyelid, periorbital, pharyngeal edema), hypersensitivity vasculitis

Cardiac disorders: Palpitations

Famciclovir may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section above are severe or do not go away:

• headache
• nausea
• vomiting
• diarrhea or loose stools
• gas
• stomach pain
• tiredness
• rash
• itching
• painful menstrual periods

If you experience any of the following side effects, call your doctor immediately:

• pain, burning, numbness, or tingling in the hands or feet

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

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Dosage Forms And Strengths

FAMVIR tablets are available in 3 strengths:

• 125 mg: White, round film-coated, biconvex, beveled edges, debossed with “FAMVIR” on one side and “125” on the other side
• 250 mg: White, round film-coated, biconvex, beveled edges, debossed with “FAMVIR” on one side and “250” on the other side
• 500 mg: White, oval film-coated, biconvex, debossed with “FAMVIR” on one side and “500” on the other side

Storage And Handling

FAMVIR tablets are supplied as film-coated tablets as follows: 125 mg in bottles of 30; 250 mg in bottles of 30; 500 mg in bottles of 30, and Single Unit Packages of 50 (intended for institutional use only).

• FAMVIR 125 mg tablet:
  White, round film-coated, biconvex, beveled edges, debossed with “FAMVIR” on one side and “125” on the other.
  125 mg 30’s      NDC 0078-0366-15
• FAMVIR 250 mg tablet:
  White, round film-coated, biconvex, beveled edges, debossed with “FAMVIR” on one side and “250” on the other.
  250 mg 30’s     NDC 0078-0367-15
• FAMVIR 500 mg tablet:
  White, oval film-coated, biconvex, debossed with “FAMVIR” on one side and “500” on the other.
  500 mg 30’s     NDC 0078-0368-15
  500 mg SUP 50’s     NDC 0078-0368-64

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature].

Distributed by: Novartis Pharmaceuticals Corporation, East Hanover, New Jersey 07936. Revised: Sep 2016

Acute renal failure is discussed in greater detail in other sections of the label [see WARNINGS AND PRECAUTIONS].

The most common adverse events reported in at least 1 indication by >10% of adult patients treated with FAMVIR are headache and nausea.

Clinical Trials Experience In Adult Patients

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of FAMVIR has been evaluated in active-and placebo-controlled clinical studies involving 816 FAMVIR-treated patients with herpes zoster (FAMVIR, 250 mg three times daily to 750 mg three times daily); 163 FAMVIR-treated patients with recurrent genital herpes (FAMVIR, 1000 mg twice daily); 1,197 patients with recurrent genital herpes treated with FAMVIR as suppressive therapy (125 mg once daily to 250 mg three times daily) 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 daily or 750 mg twice daily). Table 2 lists selected adverse events.

Table 2 Selected Adverse Events (all grades and without regard to causality) Reported by ≥2% of Patients in Placebo-Controlled Famvir Trials*

Table 3 lists selected laboratory abnormalities in genital herpes suppression trials.

Table 3 Selected Laboratory Abnormalities in Genital Herpes Suppression Studies*

In HIV-infected patients, the most frequently reported adverse events for FAMVIR (500 mg twice daily; n=150) and acyclovir (400 mg, 5x/day; n=143), respectively, were headache (17% vs. 15%), nausea (11% vs. 13%), diarrhea (7% vs. 11%), vomiting (5% vs. 4%), fatigue (4% vs. 2%), and abdominal pain (3% vs. 6%).

Postmarketing Experience

The adverse events listed below have been reported during postapproval use of FAMVIR. Because these events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:

Blood and lymphatic system disorders: Thrombocytopenia

Hepatobiliary disorders: Abnormal liver function tests, cholestatic jaundice

Immune system disorders: Anaphylactic shock, anaphylactic reaction

Nervous system disorders: Dizziness, somnolence, seizure

Psychiatric disorders: Confusion (including delirium, disorientation, and confusional state occurring predominantly in the elderly), hallucinations

Skin and subcutaneous tissue disorders: Urticaria, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, angioedema (e.g., face, eyelid, periorbital, and pharyngeal edema), hypersensitivity vasculitis

Cardiac disorders: Palpitations

Included as part of the "PRECAUTIONS" Section

Mechanism Of Action

Famciclovir is an orally administered prodrug of the antiviral agent penciclovir [see Microbiology].

Pharmacokinetics

Famciclovir is the diacetyl 6-deoxy analog of the active antiviral compound penciclovir. Following oral administration famciclovir undergoes rapid and extensive metabolism to penciclovir and little or no famciclovir is detected in plasma or urine. Penciclovir is predominantly eliminated unchanged by the kidney. Therefore, the dose of FAMVIR needs to be adjusted in patients with different degrees of renal impairment [see DOSAGE AND ADMINISTRATION].

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.

Penciclovir concentrations increased in proportion to dose over a famciclovir dose range of 125 mg to 1000 mg administered as a single dose. Table 5 shows the mean pharmacokinetic parameters of penciclovir after single administration of FAMVIR to healthy male volunteers.

Table 5 Mean Pharmacokinetic Parameters of Penciclovir in Healthy Adult Subjects*

Following oral single-dose administration of 500 mg famciclovir to 7 patients with herpes zoster, the AUC (mean ± SD), Cmax, and tmax were 12.1±1.7 mcg hr/mL, 4.0±0.7 mcg/mL, and 0.7±0.2 hours, respectively. The AUC of penciclovir was approximately 35% greater in patients with herpes zoster as compared to healthy volunteers. Some of this difference may be due to differences in renal function between the 2 groups.

There is no accumulation of penciclovir after the administration of 500 mg famciclovir three times daily for 7 days.

Penciclovir Cmax decreased approximately 50% and tmax was delayed by 1.5 hours when a capsule formulation of famciclovir was administered with food (nutritional content was approximately 910 Kcal and 26% fat). There was no effect on the extent of availability (AUC) of penciclovir. There was an 18% decrease in Cmax and a delay in tmax of about 1 hour when famciclovir was given 2 hours after a meal as compared to its administration 2 hours before a meal. Because there was no effect on the extent of systemic availability of penciclovir, FAMVIR can be taken without regard to meals.

Distribution:

The volume of distribution (Vdβ) was 1.08±0.17 L/kg in 12 healthy male subjects following a single intravenous dose of penciclovir at 400 mg administered as a 1-hour intravenous infusion. Penciclovir is <20% bound to plasma proteins over the concentration range of 0.1 to 20 mcg/mL. The blood/plasma ratio of penciclovir is approximately 1.

Metabolism:

Following oral administration, famciclovir is deacetylated and oxidized to form penciclovir. Metabolites that are inactive include 6-deoxy penciclovir, monoacetylated penciclovir, and 6-deoxy monoacetylated penciclovir (5%, <0.5% and <0.5% of the dose in the urine, respectively). Little or no famciclovir is detected in plasma or urine. An in vitro study using human liver microsomes demonstrated that cytochrome P450 does not play an important role in famciclovir metabolism. The conversion of 6-deoxy penciclovir to penciclovir is catalyzed by aldehyde oxidase. Cimetidine and promethazine, in vitro inhibitors of aldehyde oxidase, did not show relevant effects on the formation of penciclovir in vivo [see DRUG INTERACTIONS].

Elimination:

Approximately 94% of administered radioactivity was recovered in urine over 24 hours (83% of the dose was excreted in the first 6 hours) after the administration of 5 mg/kg radiolabeled penciclovir as a 1-hour infusion to 3 healthy male volunteers. Penciclovir accounted for 91% of the radioactivity excreted in the urine.

Following the oral administration of a single 500 mg dose of radiolabeled famciclovir to 3 healthy male volunteers, 73% and 27% of administered radioactivity were recovered in urine and feces over 72 hours, respectively. Penciclovir accounted for 82% and 6-deoxy penciclovir accounted for 7% of the radioactivity excreted in the urine. Approximately 60% of the administered radiolabeled dose was collected in urine in the first 6 hours.

After intravenous administration of penciclovir in 48 healthy male volunteers, mean ± SD total plasma clearance of penciclovir was 36.6±6.3 L/hr (0.48±0.09 L/hr/kg). Penciclovir renal clearance accounted for 74.5±8.8% of total plasma clearance.

Renal clearance of penciclovir following the oral administration of a single 500 mg dose of famciclovir to 109 healthy male volunteers was 27.7±7.6 L/hr. Active tubular secretion contributes to the renal elimination of penciclovir.

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. The half-life in 17 patients with herpes zoster was 2.8±1.0 hours and 2.7±1.0 hours after single and repeated doses, respectively.

Special Populations

Based on cross study comparison, penciclovir AUC was 40% higher and penciclovir renal clearance was 22% lower in elderly subjects (n=18, age 65-79 years) as compared with younger subjects. Some of this difference may be due to differences in renal function between the 2 groups. No famciclovir dosage adjustment based on age is recommended unless renal function is impaired [see DOSAGE AND ADMINISTRATION, Use In Specific Populations]

In subjects with varying degrees of renal impairment, apparent plasma clearance, renal clearance, and the plasma-elimination rate constant of penciclovir decreased linearly with reductions in renal function, after both single and repeated dosing [see Use In Specific Populations]. A dosage adjustment is recommended for patients with renal impairment [see DOSAGE AND ADMINISTRATION].

Mild or moderate hepatic impairment had no effect on the extent of availability (AUC) of penciclovir [see Use In Specific Populations]. No dosage adjustment is recommended for patients with mild or moderate hepatic impairment. The effect of severe hepatic impairment on the pharmacokinetics of penciclovir has not been evaluated.

Following oral administration of a single dose of 500 mg famciclovir to HIV-positive patients, the pharmacokinetic parameters of penciclovir were comparable to those observed in healthy subjects.

The pharmacokinetics of penciclovir were evaluated in 18 healthy male and 18 healthy female volunteers after single-dose oral administration of 500 mg famciclovir. AUC of penciclovir was 9.3±1.9 mcg hr/mL and 11.1±2.1 mcg hr/mL in males and females, respectively. Penciclovir renal clearance was 28.5±8.9 L/hr and 21.8±4.3 L/hr, respectively. These differences were attributed to differences in renal function between the 2 groups. No famciclovir dosage adjustment based on gender is recommended.

A retrospective evaluation was performed to compare the pharmacokinetic parameters obtained in black and Caucasian subjects after single and repeat once-daily, twice-daily, or three times-daily administration of famciclovir 500 mg. Data from a study in healthy volunteers (single dose), a study in subjects with varying degrees of renal impairment (single and repeat dose) and a study in subjects with hepatic impairment (single dose) did not indicate any significant differences in the pharmacokinetics of penciclovir between black and Caucasian subjects.

Microbiology

Famciclovir is a prodrug of penciclovir, which has demonstrated inhibitory activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) and varicella zoster virus (VZV). In cells infected with HSV-1, HSV-2 or VZV, the viral thymidine kinase phosphorylates penciclovir to a monophosphate form that, in turn, is converted by cellular kinases to the active form penciclovir triphosphate. Biochemical studies demonstrate that penciclovir triphosphate inhibits HSV-2 DNA polymerase competitively with deoxyguanosine triphosphate. Consequently, herpes viral DNA synthesis and, therefore, replication are selectively inhibited. Penciclovir triphosphate has an intracellular half-life of 10 hours in HSV-1-, 20 hours in HSV-2-and 7 hours in VZV-infected cells grown in culture. However, the clinical significance of the intracellular half-life is unknown.

In cell culture studies, penciclovir is inhibitory to the following herpes viruses: HSV-1, HSV-2 and VZV. The antiviral activity of penciclovir against wild type strains grown on human foreskin fibroblasts was assessed with a plaque reduction assay and staining with crystal violet 3 days postinfection for HSV and 10 days postinfection for VZV. The median EC50 values of penciclovir against laboratory and clinical isolates of HSV-1, HSV-2, and VZV were 2 μM (range 1.2 to 2.4 μM, n=7), 2.6 μM (range 1.6 to 11 μM, n=6), and 34 μM (range 6.7 to 71 μM, n=6), respectively.

Penciclovir-resistant mutants of HSV and VZV can result from mutations in the viral thymidine kinase (TK) and DNA polymerase genes. Mutations in the viral TK gene may lead to complete loss of TK activity (TK negative), reduced levels of TK activity (TK partial), or alteration in the ability of viral TK to phosphorylate the drug without an equivalent loss in the ability to phosphorylate thymidine (TK altered). The median EC50 values observed in a plaque reduction assay with penciclovir resistant HSV-1, HSV-2, and VZV were 69 μM (range 14 to 115 μM, n=6), 46 μM (range 4 to >395 μM, n=9), and 92 μM (range 51 to 148 μM, n=4), respectively. The possibility of viral resistance to penciclovir should be considered in patients who fail to respond or experience recurrent viral shedding during therapy.

Cross-resistance has been observed among HSV DNA polymerase inhibitors. The most commonly encountered acyclovir resistant mutants that are TK negative are also resistant to penciclovir.

Clinical Studies

Herpes Labialis (Cold Sores)

A randomized, double-blind, placebo-controlled trial was conducted in 701 immunocompetent adults with recurrent herpes labialis. Patients self-initiated therapy within 1 hour of first onset of signs or symptoms of a recurrent herpes labialis episode with FAMVIR 1500 mg as a single dose (n=227), FAMVIR 750 mg twice daily (n=220) or placebo (n=254) for 1 day. The median time to healing among patients with non-aborted lesions (progressing beyond the papule stage) was 4.4 days in the FAMVIR 1500 mg single-dose group (n=152) as compared to 6.2 days in the placebo group (n=168). The median difference in time to healing between the placebo and FAMVIR 1500 mg treated groups was 1.3 days (95% CI: 0.6–2.0). No differences in proportion of patients with aborted lesions (not progressing beyond the papule stage) were observed between patients receiving FAMVIR or placebo: 33% for FAMVIR 1500 mg single dose and 34% for placebo. The median time to loss of pain and tenderness was 1.7 days in FAMVIR 1500 mg single dose-treated patients vs. 2.9 days in placebo-treated patients.

Genital Herpes

A randomized, double-blind, placebo-controlled trial was conducted in 329 immunocompetent adults with recurrent genital herpes. Patients self-initiated therapy within 6 hours of the first sign or symptom of a recurrent genital herpes episode with either FAMVIR 1000 mg twice daily (n=163) or placebo (n=166) for 1 day. The median time to healing among patients with non-aborted lesions (progressing beyond the papule stage) was 4.3 days in FAMVIR-treated patients (n=125) as compared to 6.1 days in placebo-treated patients (n=145). The median difference in time to healing between the placebo and FAMVIR-treated groups was 1.2 days (95% CI: 0.5 to 2.0). Twenty-three percent of FAMVIR-treated patients had aborted lesions (no lesion development beyond erythema) vs. 13% in placebo-treated patients. The median time to loss of all symptoms (e.g., tingling, itching, burning, pain, or tenderness) was 3.3 days in FAMVIR-treated patients vs. 5.4 days in placebo-treated patients.

A randomized (2:1), double-blind, placebo-controlled trial was conducted in 304 immunocompetent black and African American adults with recurrent genital herpes. Patients self-initiated therapy within 6 hours of the first sign or symptom of a recurrent genital herpes episode with either FAMVIR 1000 mg twice daily (n=206) or placebo (n=98) for 1 day. The median time to healing among patients with non-aborted lesions was 5.4 days in FAMVIR-treated patients (n=152) as compared to 4.8 days in placebo-treated patients (n=78). The median difference in time to healing between the placebo and FAMVIR-treated groups was -0.26 days (95% CI: -0.98 to 0.40).

Two randomized, double-blind, placebo-controlled, 12-month trials were conducted in 934 immunocompetent adults with a history of 6 or more recurrences of genital herpes episodes per year. Comparisons included FAMVIR 125 mg three times daily, 250 mg twice daily, 250 mg three times daily, and placebo. At 12 months, 60% to 65% of patients were still receiving FAMVIR and 25% were receiving placebo treatment. Recurrence rates at 6 and 12 months in patients treated with the 250 mg twice daily dose are shown in Table 6.

Table 6 Recurrence Rates at 6 and 12 Months in Adults with Recurrent Genital Herpes on Suppressive Therapy

FAMVIR-treated patients had approximately 1/5 the median number of recurrences as compared to placebo-treated patients. Higher doses of FAMVIR were not associated with an increase in efficacy.

Recurrent Orolabial Or Genital Herpes In HIV-Infected Patients

A randomized, double-blind trial compared famciclovir 500 mg twice daily for 7 days (n=150) with oral acyclovir 400 mg 5 times daily for 7 days (n=143) in HIV-infected patients with recurrent orolabial or genital herpes treated within 48 hours of lesion onset. Approximately 40% of patients had a CD4 + count below 200 cells/mm3, 54% of patients had anogenital lesions and 35% had orolabial lesions. Famciclovir therapy was comparable to oral acyclovir in reducing new lesion formation and in time to complete healing.

Herpes Zoster (Shingles)

Two randomized, double-blind trials, 1 placebo-controlled and 1 active-controlled, were conducted in 964 immunocompetent adults with uncomplicated herpes zoster. Treatment was initiated within 72 hours of first lesion appearance and was continued for 7 days.

In the placebo-controlled trial, 419 patients were treated with either FAMVIR 500 mg three times daily (n=138), FAMVIR 750 mg three times daily (n=135) or placebo (n=146). The median time to full crusting was 5 days among FAMVIR 500 mg-treated patients as compared to 7 days in placebo-treated patients. The times to full crusting, loss of vesicles, loss of ulcers, and loss of crusts were shorter for FAMVIR 500 mg-treated patients than for placebo-treated patients in the overall study population. The effects of FAMVIR were greater when therapy was initiated within 48 hours of rash onset; it was also more profound in patients 50 years of age or older. Among the 65.2% of patients with at least 1 positive viral culture, FAMVIR treated patients had a shorter median duration of viral shedding than placebo-treated patients (1 day and 2 days, respectively).

There were no overall differences in the duration of pain before rash healing between FAMVIR-and placebo-treated groups. In addition, there was no difference in the incidence of pain after rash healing (postherpetic neuralgia) between the treatment groups. In the 186 patients (44.4% of total study population) who developed postherpetic neuralgia, the median duration of postherpetic neuralgia was shorter in patients treated with FAMVIR 500 mg than in those treated with placebo (63 days and 119 days, respectively). No additional efficacy was demonstrated with higher dose of FAMVIR.

In the active-controlled trial, 545 patients were treated with 1 of 3 doses of FAMVIR three times daily or with acyclovir 800 mg five times daily. Times to full lesion crusting and times to loss of acute pain were comparable for all groups and there were no statistically significant differences in the time to loss of postherpetic neuralgia between FAMVIR and acyclovir-treated groups.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Famvir, there are no specific foods that you must exclude from your diet when receiving this medication.

• Store Famvir at room temperature between 59° and 86°F (15° to 30°C).
• Keep Famvir and all medicines out of reach from children.

Famvir is not a cure for herpes. It is not known if Famvir tablets can stop the spread of herpes to others. If you are sexually active, you can pass herpes to your partner even if you are taking Famvir tablets. Herpes can be transmitted even if you do not have active symptoms. You should continue to practice safer sex to lower the chances of spreading genital herpes to others. Do not have sexual contact with your partner during an outbreak of genital herpes or if you have any symptoms of genital herpes. Use a condom made of latex or polyurethane when you have a sexual contact. Ask your healthcare provider for more information about safer sex practices.

Administration

Oral Administration

Administer orally without regard to meals.1

Dosage

Pediatric Patients

Adolescents should receive dosage recommended for adults with genital herpes.27 (See Adults under Dosage and Administration.)

HIV-infected adolescents: 250 mg twice daily for chronic suppressive or maintenance therapy (secondary prophylaxis) of HSV† infections in those with frequent or severe recurrences.28

Local dermatomal herpes zoster in HIV-infected adolescents†: 500 mg three times daily for 7–10 days recommended by CDC and other experts.46

Adults

Immunocompetent adults: 250 mg 3 times daily for 7–10 days recommended by CDC and others; duration of treatment may be extended if healing is incomplete after 10 days.26 36 37

HIV-infected adults: 500 mg twice daily for 7–14 days recommended by CDC and others.46

Immunocompetent adults: 1 g twice daily for 1 day1 26 27 or 125 mg twice daily for 5 days.26 27 36 37

HIV-infected adults: 500 mg twice daily for 5–10 days recommended by CDC and others;26 37 46 alternatively, continue for 7–14 days.46

Initiate therapy at first sign or symptom of an episode;1 efficacy not established if initiated >6 hours after onset of signs or symptoms.1

Immunocompetent adults: 250 mg twice daily.1 26 36 37

HIV-infected adults: 500 mg twice daily recommended by CDC.26

Manufacturer states chronic suppressive therapy may be given for up to 1 year.1

Because frequency of recurrent episodes diminishes over time in many patients, CDC and others recommend that suppressive antiviral therapy be discontinued periodically (e.g., once yearly) to assess the need for continued therapy.26 36

Immunocompetent adults: 1.5 g as a single dose.1

Initiate therapy at first prodromal symptom (e.g., tingling, itching, burning).1

HIV-infected adults: 500 mg every 12 hours for 7 days for treatment of recurrent infections (orolabial or genital herpes).1 Some experts recommend 7–14 days.46

HIV-infected adults: 250 mg twice daily for chronic suppressive or maintenance therapy (secondary prophylaxis) of HSV† in those with frequent or severe recurrences.28

Immunocompetent adults: 500 mg every 8 hours for 7 days.1 27 37 47

Local dermatomal herpes zoster in HIV-infected adults†: 500 mg three times daily for 7–10 days recommended by CDC and other experts.46

Initiate therapy promptly as soon as diagnosed;1 efficacy not established if initiated >72 hours after rash onset.1

Special Populations

Renal Impairment

Storage

Oral

15–30°C.1

• Advise patients that famciclovir is not a cure for genital herpes, and there are no data evaluating whether famciclovir prevents transmission of genital herpes to others.1

• Importance of avoiding sexual contact with uninfected partners while lesions and/or symptoms of genital herpes are present since there is a risk of transmission.1 Genital herpes can be transmitted in the absence of symptoms through asymptomatic viral shedding.1

• Advise patients to avoid driving or operating machinery if they experience dizziness, drowsiness, confusion, or other CNS disturbances; there is no evidence that famciclovir affects ability to drive or operate machinery.1

• Importance of informing clinician of existing or contemplated concomitant therapy, including prescription or nonprescription drugs.1

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.1

• Importance of advising patients of other important precautionary information.1 (See Cautions.)

Use Famvir as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take with or without food.
• To gain the most benefit, do not miss doses.
• Use as you have been told, even if your signs get better.

What do I do if I miss a dose?

• Take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.

     Immunocompetent Adult Patients

Herpes labialis (cold sores): Famvir is indicated for the treatment of recurrent herpes labialis.

Genital herpes: 

Recurrent episodes: Famvir is indicated for the treatment of recurrent episodes of genital herpes. The efficacy of Famvir when initiated more than 6 hours after onset of symptoms or lesions has not been established.

Suppressive therapy: Famvir is indicated for chronic suppressive therapy of recurrent episodes of genital herpes. The efficacy and safety of Famvir for the suppression of recurrent genital herpes beyond 1 year have not been established.

Herpes zoster (shingles): Famvir is indicated for the treatment of herpes zoster. The efficacy of Famvir when initiated more than 72 hours after onset of rash has not been established.

     HIV-Infected Adult Patients

Recurrent orolabial or genital herpes: Famvir is indicated for the treatment of recurrent episodes of orolabial or genital herpes in HIV-infected adults. The efficacy of Famvir when initiated more than 48 hours after onset of symptoms or lesions has not been established.

Limitation of Use

The efficacy and safety of Famvir have not been established for:

• Patients less than 18 years of age
  
• Patients with first episode of genital herpes
  
• Patients with ophthalmic zoster
  
• Immunocompromised patients other than for the treatment of recurrent orolabial or genital herpes in HIV-infected patients
  
• Black and African American patients with recurrent genital herpes

Famvir may be taken with or without food.

     Dosing Recommendation in Immunocompetent Adult Patients

Herpes labialis (cold sores): The recommended dosage of Famvir for the treatment of recurrent herpes labialis is 1500 mg as a single dose. Therapy should be initiated at the first sign or symptom of herpes labialis (e.g., tingling, itching, burning, pain, or lesion).

Genital herpes: 

Recurrent episodes: The recommended dosage of Famvir for the treatment of recurrent episodes of genital herpes is 1000 mg twice daily for 1 day. Therapy should be initiated at the first sign or symptom of a recurrent episode (e.g., tingling, itching, burning, pain, or lesion).

Suppressive therapy: The recommended dosage of Famvir for chronic suppressive therapy of recurrent episodes of genital herpes is 250 mg twice daily.

Herpes zoster (shingles): The recommended dosage of Famvir for the treatment of herpes zoster is 500 mg every 8 hours for 7 days. Therapy should be initiated as soon as herpes zoster is diagnosed.

     Dosing Recommendation in HIV-Infected Adult Patients

Recurrent orolabial or genital herpes: The recommended dosage of Famvir for the treatment of recurrent orolabial or genital herpes in HIV-infected patients is 500 mg twice daily for 7 days. Therapy should be initiated at the first sign or symptom of a recurrent episode (e.g., tingling, itching, burning, pain, or lesion).

     Dosing Recommendation in Patients with Renal Impairment

Dosage recommendations for adult patients with renal impairment are provided in Table 1 [see Use in Specific Populations (8.6), Clinical Pharmacology (12.3)].

*Hemodialysis