pharmacopeia
GET
/api/v1/drug/acyclovir
2D structure
2-amino-9-(2-hydroxyethoxymethyl)-1H-purin-6-one
SMILES C1=NC2=C(N1COCCO)N=C(NC2=O)N
InChIKey MKUXAQIIEYXACX-UHFFFAOYSA-N

Mechanism of action

Sourced from openFDA

Mechanism of Antiviral Action: Acyclovir is a synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV). The inhibitory activity of acyclovir is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV.

DNA Polymerase

Indications

Sourced from openFDA
  • Herpes Zoster Infections : Acyclovir is indicated for the acute treatment of herpes zoster (shingles). Genital Herpes : Acyclovir is indicated for the treatment of initial episodes and the management of recurrent episodes of genital herpes.ICD-10: A60.9, B02.9

Contraindications

Sourced from openFDA
  • Acyclovir is contraindicated for patients who develop hypersensitivity to acyclovir or valacyclovir.contraindicated

Dosage & administration

Sourced from openFDA

Acute Treatment of Herpes Zoster : 800 mg every 4 hours orally, 5 times daily for 7 to 10 days. Genital Herpes : Treatment of Initial Genital Herpes: 200 mg every 4 hours, 5 times daily for 10 days. Chronic Suppressive Therapy for Recurrent Disease: 400 mg 2 times daily for up to 12 months, followed by re-evaluation. Alternative regimens have included doses ranging from 200 mg 3 times daily to 200 mg 5 times daily. The frequency and severity of episodes of untreated genital herpes may change over time. After 1 year of therapy, the frequency and severity of the patient's genital herpes infection should be re-evaluated to assess the need for continuation of therapy with acyclovir. Intermittent Therapy: 200 mg every 4 hours, 5 times daily for 5 days. Therapy should be initiated at the earliest sign or symptom (prodrome) of recurrence. Treatment of Chickenpox : Children (2 years of age and older): 20 mg/kg per dose orally 4 times daily (80 mg/kg/day) for 5 days. Children over 40 kg should receive the adult dose for chickenpox. Adults and Children over 40 kg: 800 mg 4 times daily for 5 days. Intravenous acyclovir is indicated for the treatment of varicella-zoster infections in immunocompromised patients. When therapy is indicated, it should be initiated at the earliest sign or symptom of chickenpox. There is no information about the efficacy of therapy initiated more than 24 hours after onset of signs and symptoms.

Warnings & precautions

Sourced from openFDA

Acyclovir capsules 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.

Adverse reactions

Sourced from openFDA

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 times daily 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%). Herpes Zoster : The most frequent adverse event reported during 3 clinical trials of treatment of herpes zoster (shingles) with 800 mg of oral acyclovir 5 times daily for 7 to 10 days in 323 patients was malaise (11.5%). The 323 placebo recipients reported malaise (11.1%). Chickenpox : The most frequent adverse event reported during 3 clinical trials of treatment of chickenpox with oral acyclovir at doses of 10 to 20 mg/kg 4 times daily for 5 to 7 days or 800 mg 4 times daily for 5 days in 495 patients was diarrhea (3.2%). The 498 patients receiving placebo reported diarrhea (2.2%). Observed During Clinical Practice : In addition to adverse events reported from clinical trials, the following events have been identified during post-approval use of acyclovir.

Use in specific populations

Sourced from openFDA

Pregnancy: Teratogenic Effects: Pregnancy Category B. Acyclovir administered during organogenesis was not teratogenic in the mouse (450 mg/kg/day, p.o.), rabbit (50 mg/kg/day, s.c. and IV), or rat (50 mg/kg/day, s.c.). These exposures resulted in plasma levels 9 and 18, 16 and 106, and 11 and 22 times, respectively, human levels. There are no adequate and well-controlled studies in pregnant women. A prospective epidemiologic registry of acyclovir use during pregnancy was established in 1984 and completed in April 1999. There were 749 pregnancies followed in women exposed to systemic acyclovir during the first trimester of pregnancy resulting in 756 outcomes. The occurrence rate of birth defects approximates that found in the general population. However, the small size of the registry is insufficient to evaluate the risk for less common defects or to permit reliable or definitive conclusions regarding the safety of acyclovir in pregnant women and their developing fetuses. Acyclovir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Pharmacokinetics

Sourced from openFDA
Metabolism
The pharmacokinetics of acyclovir after oral administration have been evaluated in healthy volunteers and in immunocompromised patients with herpes simplex or varicella-zoster virus infection. Acyclovir pharmacokinetic parameters are summarized in Table 1 .

Overdosage

Sourced from openFDA

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 ).

Approval history

Sourced from openFDA
  • Mar 29, 1982NDANDA018604Bausch
  • Apr 28, 1997ANDAANDA074738Actavis Mid Atlantic
  • Oct 31, 1997ANDAANDA074891Heritage
  • Oct 31, 1997ANDAANDA074889Heritage
  • May 13, 1998ANDAANDA074930Fresenius Kabi Usa
  • Dec 30, 2002NDANDA021478Bausch
  • Jul 31, 2009NDANDA022436Bausch
  • Mar 29, 2019NDANDA202408Fera Pharms Llc

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
112,881 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Fatigue7,8597.0%
  2. 2Diarrhoea7,2366.4%
  3. 3Off Label Use6,0845.4%
  4. 4Pneumonia5,6115.0%
  5. 5Nausea5,5154.9%
  6. 6Pyrexia4,8904.3%
  7. 7Death4,8134.3%
  8. 8Drug Ineffective4,6574.1%
  9. 9Rash4,2263.7%
  10. 10Dyspnoea3,5853.2%
  11. 11Asthenia3,3092.9%
  12. 12Headache3,2112.8%
  13. 13Neutropenia3,1862.8%
  14. 14White Blood Cell Count Decreased3,1722.8%
  15. 15Platelet Count Decreased3,0732.7%

Literature

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Recent PubMed references pinned to Acyclovir as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 432 ClinicalTrials.gov registrations naming Acyclovir as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Acyclovir work?
Mechanism of Antiviral Action: Acyclovir is a synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV). The inhibitory activity of acyclovir is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV.
What is Acyclovir used for?
According to FDA labeling, Acyclovir carries indications including: Herpes Zoster Infections : Acyclovir is indicated for the acute treatment of herpes zoster (shingles). Genital Herpes : Acyclovir is indicated for the treatment of initial episodes and the management of recurrent episodes of genital herpes.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Acyclovir?
Acyclovir is classified as Antivirals, Nucleosides and nucleotides excl. reverse transcriptase inhibitors, Herpes Simplex Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpes Zoster Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpesvirus Nucleoside Analog DNA Polymerase Inhibitor, DNA Polymerase Inhibitors, Decreased DNA Replication.
What are the brand names for Acyclovir?
Acyclovir is marketed under brand names including Avaclyr, Sitavig, Xerese, Zovirax.
What are the contraindications for Acyclovir?
Acyclovir labeling lists contraindications including: Acyclovir is contraindicated for patients who develop hypersensitivity to acyclovir or valacyclovir.. Always consult the full prescribing information and a clinician.
Note. Data for acyclovir is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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