Acyclovir: uses, appearance and warnings

Herpes Zoster Infections: Acyclovir tablets are indicated for the acute treatment of herpes zoster (shingles). Genital Herpes: Acyclovir tablets are indicated for the treatment of initial episodes and the management of recurrent episodes of genital herpes. Chickenpox: Acyclovir tablets are indicated for the treatment of chickenpox (varicella).

Acyclovir Tablets, USP are available as: 400 mg Bottles of 100 NDC 23155- 227-01 Bottles of 500 NDC 23155- 227-05 Each round tablet is white to off-white and debossed with HP 227 on one side and plain on the other side. Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature] and protect from light and moisture. 800 mg Bottles of 100 NDC 23155- 228-01 Bottles of 500 NDC 23155- 228-05 Each oval tablet is white to off-white and debossed with HP 228 on one side and plain on the other side. Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature] and protect from light and moisture. Distributed by: Avet Pharmaceuticals Inc. East Brunswick, NJ 08816 1.866.901.DRUG (3784) Revised: 07/2026 Logo

Acyclovir is contraindicated in patients who have had a demonstrated clinically significant hypersensitivity reaction [e.g., anaphylaxis, severe cutaneous adverse reactions (SCARs)] to acyclovir, valacyclovir, or any component of the formulation (see WARNINGS and ADVERSE REACTIONS ).

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. Severe cutaneous adverse reactions (SCARs), including acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens- Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and erythema multiforme (EM) have been reported with acyclovir (see CONTRAINDICATIONS and ADVERSE REACTIONS ). Discontinue acyclovir immediately if a painful rash with mucosal involvement or a progressive severe rash develops. Closely monitor clinical status and initiate appropriate therapy. Acyclovir is contraindicated in patients who have developed SCARs with the use of acyclovir or valacyclovir, or any component of the formulation (see CONTRAINDICATIONS and ADVERSE REACTIONS ).

Herpes Simplex: Short-Term Administration: The most frequent adverse events reported during clinical trials of treatment of genital herpes with acyclovir 200 mg administered orally 5 timesdaily every 4 hours for 10 days were nausea and/or vomiting in 8 of 298 patient treatments (2.7%). Nausea and/or vomiting occurred in 2 of 287 (0.7%) patients who received placebo. Long-Term Administration: The most frequent adverse events reported in a clinical trial for the prevention of recurrences with continuous administration of 400 mg (two 200-mg capsules) 2 times daily for 1 year in 586 patients treated with acyclovir were nausea (4.8%) and diarrhea (2.4%). The 589 control patients receiving intermittent treatment of recurrences with acyclovir for 1 year reported diarrhea (2.7%), nausea (2.4%), and headache (2.2%). …