valacyclovir (Valtrex)
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Introduction
Tradename: Valtrex.
Indications
Dosage
Tabs: 500 mg ($3.50 in 2003)
Dosage adjustment in renal failure
Table
| creatinine clearance | dosage |
|---|---|
| > 50-90 mL/min | 1.0 mg every BID-TID |
| 10-50 mL/min* | 1.0 mg QD-BID |
| < 10 mL/min# | 0.5 mg QD |
* QD dosing for creatinine clearance < 30 mL/min[3]
# dose after hemodialysis
Pharmacokinetics
- prodrug of acyclovir
- achieves serum levels 4-5 fold greater than acyclovir
- achieves serum levels comparable to those obtained with intravenous acyclovir
- elimination 1/2life 2.5 hours (3.3 hours ESRD)
elimination via kidney
1/2life = 2.5 hours
Adverse effects
- thrombotic thrombocytopenic purpura (TTP)
- hemolytic uremic syndrome (HUS)
- nephrotoxicity
- hepatotoxicity
- psychomotor disturbances
- neurotoxity[10] (in order of frequency)
- disorientation
- diminished level of consciousness
- hallucinations
- agitation
- dysarthria
- seizures/myoclonus
- coma
- tremor
- ataxia
- aphasia
- delirium
Mechanism of action
- prodrug of acyclovir
- reduces transmission by 50%[5]
More general terms
Additional terms
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- ↑ 3.0 3.1 3.2 Prescriber's Letter 8(8): 44, 2001
- ↑ Sanford Guide to antimicrobial therapy 2001
- ↑ 5.0 5.1 5.2 Prescriber's Letter 9(11):62 2002
- ↑ 6.0 6.1 Prescriber's Letter 10(10):56 2003
- ↑ Vigil KJ, Chemaly RF. Valacyclovir: approved and off-label uses for the treatment of herpes virus infections in immunocompetent and immunocompromised adults. Expert Opin Pharmacother. 2010 Aug;11(11):1901-13 PMID: https://www.ncbi.nlm.nih.gov/pubmed/20536295
- ↑ Leone PA et al, Valacyclovir for episodic treatment of genital herpes: a shorter 3-day treatment course compared with 5-day treatment. Clin Infect Dis 34:958, 2002 PMID: https://www.ncbi.nlm.nih.gov/pubmed/11880962
- ↑ 9.0 9.1 Deprecated Reference
- ↑ 10.0 10.1 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
Murakami T, Akimoto T, Okada M, et al. Valacyclovir neurotoxicity and nephrotoxicity in an elderly patient complicated by hyponatremia. Drug Target Insights. 2018 Jun 25:12:1177392818782899 PMID: https://www.ncbi.nlm.nih.gov/pubmed/30013310 PMCID: PMC6043912 Free PMC article - ↑ Department of Veterans Affairs, VA National Formulary
Database
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=60773
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5281018
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=60772
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5281019
- PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5647