Famciclovir: uses, appearance and warnings

Famciclovir, 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 recurrent episodes • Herpes zoster (shingles) Human Immunodeficiency Virus (HIV) -Infected Adult Patients ( 1.2 ) • Treatment of recurrent episodes of orolabial or genital herpes Limitation of Use The efficacy and safety of famciclovir tablets have not been established for: • Patients with first episode of genital herpes • Patients with ophthalmic zoster • Immunocompromised patients other than for the treatment of recurrent episodes of orolabial or genital herpes in HIV- infected patients • Black and African American patients with recurrent genital herpes 1.1 Immunocompetent Adult Patients Herpes labialis(cold sores): Famciclovir tablets are indicated for the treatment of recurrent herpes labialis in adult patients. Genital herpes: Recurrent episodes: Famciclovir tablets are indicated for the treatment of recurrent episodes of genital herpes. The efficacy of famciclovir tablets when initiated more than 6 hours after onset of symptoms or lesions has not been established. Suppressive therapy: Famciclovir tablets are indicated for chronic suppressive therapy of recurrent episodes of genital herpes in adult patients. The efficacy and safety of famciclovir tablets for the suppression of recurrent genital herpes beyond 1 year have not been established. Herpes zoster (shingles): Famciclovir tablets are indicated for the treatment of herpes zoster in adult patients. The efficacy of famciclovir tablets when initiated more than 72 hours after onset of rash has not been established. 1.2 HIV-Infected Adult Patients Recurrent orolabial or genital herpes: Famciclovir tablets are is indicated for the treatment of recurrent episodes of orolabial or genital herpes in HIV-infected adults. The efficacy of famciclovir tablets when initiated more than 48 hours after onset of symptoms or lesions has not been established. Limitation of Use The efficacy and safety of famciclovir tablets have not been established for: • 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

Famciclovir tablets, USP are available in 3 strengths: •125 mg: White to off white, round, film-coated, biconvex, engraved with "ML 67" on one side and plain on the other side. •250 mg: White to off white, round, film-coated, biconvex, engraved with "ML 70" on one side and plain on the other side. •500 mg: White to off white, oval, film-coated, biconvex, engraved with "ML 72" on one side and plain on the other side. Tablets : 125 mg, 250 mg, 500 mg ( 3 )

Famciclovir tablets, USP 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 • Famciclovir tablets, USP 125 mg: White to off white, round film-coated, biconvex, engraved with "ML 67" on one side and plain on the other side. 125 mg 30's ......................................NDC 33342-024-07 • Famciclovir tablets, USP 250 mg: White to off white, round film-coated, biconvex, engraved with "ML 70" on one side and plain on the other side. 250 mg 30's ......................................NDC 33342-025-07 • Famciclovir tablets, USP 500 mg: White to off white, oval, film-coated, biconvex, engraved with "ML 72" on one side and plain on the other side. 500 mg 30's .....................................NDC33342-026-07 Store at 20° to 25°C (68°to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Preserve in tight containers. Store at controlled room temperature.

Famciclovir tablets are contraindicated in patients with known hypersensitivity to the product, its components, or Denavir ® (penciclovir cream). Known hypersensitivity to the product, its components, or Denavir ® (penciclovir cream) ( 4 )

Acute renal failure: May occur in patients with underlying renal disease who receive higher than recommended doses of famciclovir for their level of renal function. Reduce dosage in patients with renal impairment ( 2.3, 8.6 ) 5.1 Acute Renal Failure Cases of acute renal failure have been reported in patients with underlying renal disease who have received inappropriately high doses of famciclovir for their level of renal function. Dosage reduction is recommended when administering famciclovir tablets to patients with renal impairment [see Dosage and Administration ( 2.3 ), Use in Specific Populations ( 8.6 )].

Acute renal failure is discussed in greater detail in other sections of the label [see Warnings and Precautions ( 5 )]. The most common adverse events reported in at least 1 indication by greater than 10% of adult patients treated with famciclovir are headache and nausea. The most common adverse events reported in at least 1 indication by greater than 10% of adult patients are headache and nausea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Macleods Pharma USA, Inc. at 1-888-943-3210 or 1-855-926-3384 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 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. …

Probenecid: May increase penciclovir levels. Monitor for evidence of penciclovir toxicity ( 7.2 ) 7.1 Potential for Famciclovir to Affect Other Drugs The steady-state pharmacokinetics of digoxin were not altered by concomitant administration of multiple doses of famciclovir (500 mg three times daily). No clinically significant effect on the pharmacokinetics of zidovudine, its metabolite zidovudine glucuronide, or emtricitabine was observed following a single oral dose of 500 mg famciclovir coadministered with zidovudine or emtricitabine. An in vitro study using human liver microsomes suggests that famciclovir is not an inhibitor of CYP3A4 enzymes. …