acyclovir (ACV, Zovirax, Sitavig)
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Introduction
Tradename: Zovirax, Sitavig.
Indications
- treatment of susceptible viral infections
- Herpes simplex type 1 & 2 infections
- Varicella zoster infections
- Epstein-Barr virus
- mucocutaneous infections
- neonatal infections[7]
- empiric treatment of meningoencephalitis
Dosage
- 5-10 mg/kg IV every 8 hours, each dose over 1 hour.
- 1st episode genital herpes: 400 mg PO TID x 7-10 days.
- Recurrent genital herpes:
- Herpes prophylaxis: 400 mg PO BID.
- Herpes simplex encephalitis:
- 10 mg/kg IV every 8 hours for 10 days.
- Herpes Zoster: 800 mg PO 5 times/day for 7-10 days.
- Varicella: 20 mg/kg up to 800 mg PO QID for 5 days.
- Mucocutaneous Herpes in an immunocompromised host:
- Varicella or Herpes zoster in an immunocompromised host:
- 10 m/kg IV every 8 hours for 7 days
- Herpes simplex (cold sore)
Tabs: 200 & 800 mg.
Suspension: 200 mg/5 mL.
Topical agent: 5% ointment 6 times/day for 7 days.
Tubes: 3 & 15 g.
Dosage adjustment in renal failure
Adjustment of oral dose in renal failure
| creatinine clearance | adjusted dose | dosing interval |
|---|---|---|
| > 50 mL/min | 100% | every 8 hours |
| 25-50 mL/min | 100% | every 12 hours |
| 11-15 mL/min | 100% | every 24 hours |
| > 10 mL/min | 50% | every 24 hours |
Adjustment of IV dose in renal failure
| creatinine clearance | adjusted dose[9] | |
|---|---|---|
| > 50 mL/min | 10 mg/kg q8h 25-50 mL/min | full dose q12 hours |
| 11-25 mL/min | full dose q24 hours | |
| 0-10 mL/min | half dose q24 hours |
* intravenous normal saline to maintain urine output > 75 mL/hour if rise in serum creatinine[10]
| creatinine clearance | adjusted dose[9] | |
|---|---|---|
| > 50 mL/min | 10 mg/kg q8h 25-50 mL/min | full dose q12 hours |
| 11-25 mL/min | full dose q24 hours | |
| 0-10 mL/min | half dose q24 hours |
* intravenous normal saline to maintain urine output > 75 mL/hour if rise in serum creatinine[10]
Pharmacokinetics
- oral bioavailability is 15-30%
- food does not appear to affect absorption
- peak serum levels
- 1.5-2 hours after oral dose
- 1 hours after IV administration
- widely distributed to tissues
- cerebrospinal fluid levels are about 50% of serum levels
- protein binding 9-33%
- metabolized by the liver[3]
- eliminated by kidney (primary mechanism)[1][3]
- elimination 1/2life 2-3 hours
- 60% eliminated by hemodialysis
- dose adjustment in renal failure
elimination via kidney
elimination via liver
1/2life = 2-3 hours
protein binding = 9-33 %
elimination by hemodialysis = +
Adverse effects
- common (> 10%)
- headache
- inflammation at site of injection
- less common (1-10%)
- uncommon (< 1%)
- mental depression, insomnia, anorexia, LFT elevation, sore throat, lethargy, diaphoresis
- other
- phlebitis[2]
- nephrotoxicity:
- neurotoxity[11] (in order of frequency)
- disorientation
- diminished level of consciousness
- hallucinations
- agitation
- dysarthria
- seizures/myoclonus
- coma
- tremor
- ataxia
- aphasia
- delirium
* intravenous normal saline to maintain urine output > 75 mL/hour if rise in serum creatinine[10]
Drug interactions
- probenecid increases oral bioavailability & 1/2life of acyclovir
- zidovudine results in an increase in drowsiness & lethargy
Laboratory
- specimen:
- methods: HPLC, RIA, MB
- laboratory tests
Mechanism of action
- viral thymidine kinase & cellular enzymes convert acyclovir to its active form
- acyclovir triphosphate is a competitive inhibitor of viral DNA polymerase
- Herpes zoster is 8-10 times less sensitive to acyclovir than Herpes simplex
- Herpes virus resistance develops as the virus loses thymidine kinase activity
More general terms
Component of
References
- ↑ 1.0 1.1 The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ 2.0 2.1 Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ 3.0 3.1 3.2 Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 4.0 4.1 Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- ↑ Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
- ↑ 6.0 6.1 Journal Watch 22(9):69, 2002 Wald A et al, Two-day regimen of acyclovir for treatment of recurrent genital herpes simplex virus type 2 infection. Clin Infect Dis 34:944, 2002 PMID: https://www.ncbi.nlm.nih.gov/pubmed/11880960
- ↑ 7.0 7.1 Deprecated Reference
- ↑ 8.0 8.1 8.2 Prescriber's Letter 21(9): 2014 Treatment of Cold Sores Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=300905&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 9.0 9.1 9.2 acyclovir (Rx) Medscape https://reference.medscape.com/drug/zovirax-acyclovir-342601
- ↑ 10.0 10.1 10.2 10.3 NEJM Knowledge+ Complex Medical Care
- ↑ 11.0 11.1 Brandariz-Nunez D, Correas-Sanahuja M, Maya-Gallego S, et al. Neurotoxicity associated with acyclovir and valacyclovir: A systematic review of cases. Journal of Clinical Pharmacy and Therapeutics. 2021;46(4):918-926. PMID: https://www.ncbi.nlm.nih.gov/pubmed/34146428