ACYCLOVIR TABLETS, USP 400 mg and 800 mg

DESCRIPTION

DESCRIPTION SECTION

Acyclovir is a synthetic nucleoside analogue active against herpes viruses. Acyclovir tablets are a formulation for oral administration. Each 800 mg tablet of acyclovir contains 800 mg of acyclovir and the inactive ingredients colloidal silicon dioxide, croscarmellose sodium, magnesium stearate and microcrystalline cellulose. Each 400 mg tablet of acyclovir contains 400 mg of acyclovir and the inactive ingredients colloidal silicon dioxide, croscarmellose sodium, magnesium stearate and microcrystalline cellulose. Acyclovir is a white, crystalline powder with the molecular formula C 8 H 11 N 5 O 3 and a molecular weight of 225.2. The maximum solubility in water at 37°C is 2.5 mg/mL. The pKa’s of acyclovir are 2.27 and 9.25. The chemical name of acyclovir is 2-amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6 H -purin-6-one; it has the following structural formula:

VIROLOGY

SPL UNCLASSIFIED SECTION

CLINICAL PHARMACOLOGY

CLINICAL PHARMACOLOGY SECTION

INDICATIONS AND USAGE

INDICATIONS & USAGE SECTION

CONTRAINDICATIONS

CONTRAINDICATIONS SECTION

Acyclovir is contraindicated for patients who develop hypersensitivity to acyclovir or valacyclovir.

WARNINGS

WARNINGS SECTION

Acyclovir tablets are intended for oral ingestion only. Renal failure, in some cases resulting in death, has been observed with acyclovir therapy (see ADVERSE REACTIONS: Observed During Clinical Practice and OVERDOSAGE ). Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), which has resulted in death, has occurred in immunocompromised patients receiving acyclovir therapy.

PRECAUTIONS

PRECAUTIONS SECTION

Dosage adjustment is recommended when administering acyclovir to patients with renal impairment (see DOSAGE AND ADMINISTRATION) . Caution should also be exercised when administering acyclovir to patients receiving potentially nephrotoxic agents since this may increase the risk of renal dysfunction and/or the risk of reversible central nervous system symptoms such as those that have been reported in patients treated with intravenous acyclovir. Adequate hydration should be maintained.

ADVERSE REACTIONS

ADVERSE REACTIONS SECTION

OVERDOSAGE

OVERDOSAGE SECTION

Overdoses involving ingestion of up to 100 capsules (20 g) have been reported. Adverse events that have been reported in association with overdosage include agitation, coma, seizures, and lethargy. Precipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. Overdosage has been reported following bolus injections or inappropriately high doses and in patients whose fluid and electrolyte balance were not properly monitored. This has resulted in elevated BUN and serum creatinine and subsequent renal failure. In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored (see DOSAGE AND ADMINISTRATION ).

DOSAGE AND ADMINISTRATION

DOSAGE & ADMINISTRATION SECTION

HOW SUPPLIED

HOW SUPPLIED SECTION

Product: 50090-0643 NDC: 50090-0643-0 90 TABLET in a BOTTLE NDC: 50090-0643-1 21 TABLET in a BOTTLE

acyclovir

PACKAGE LABEL.PRINCIPAL DISPLAY PANEL