Valaciclovir

Valaciclovir
Clinical data
Trade names	Valtrex, Zelitrex, others
Other names	valacyclovir, valacyclovir hydrochloride (USAN US)
AHFS/Drugs.com	Monograph
MedlinePlus	a695010
License data	US DailyMed: Valacyclovir;
Pregnancy; category	AU: B3;
Routes of; administration	By mouth
Drug class	Antiviral
ATC code	J05AB11 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); UK: POM (Prescription only); US: ℞-only; In general: ℞ (Prescription only);
Pharmacokinetic data
Bioavailability	55%
Protein binding	13–18%
Metabolism	Liver (to aciclovir)
Elimination half-life	<30 minutes (valaciclovir);; 2.5–3.6 hours (aciclovir)
Excretion	Kidney 40–50% (aciclovir),; faecal 47% (aciclovir)
Identifiers
	IUPAC name 2-[(2-Amino-6-oxo-1H-purin-9-yl)methoxy]ethyl (2S)-2-amino-3-methylbutanoate;
CAS Number	124832-26-4 ; as HCl: 124832-27-5;
PubChem CID	135398742; as HCl: 135398741;
IUPHAR/BPS	4824;
DrugBank	DB00577 ; as HCl: DBSALT000289;
ChemSpider	54770 ;
UNII	MZ1IW7Q79D; as HCl: G447S0T1VC;
KEGG	D08664 ; as HCl: D00398;
ChEBI	CHEBI:35854 ; as HCl: CHEBI:9919;
ChEMBL	ChEMBL1349 ; as HCl: ChEMBL1201110;
NIAID ChemDB	070982;
CompTox Dashboard (EPA)	DTXSID1023732 ;
ECHA InfoCard	100.114.479
Chemical and physical data
Formula	C13H20N6O4
Molar mass	324.341 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C(OCCOCn1c2N\C(=N/C(=O)c2nc1)N)[C@@H](N)C(C)C;
	InChI InChI=1S/C13H20N6O4/c1-7(2)8(14)12(21)23-4-3-22-6-19-5-16-9-10(19)17-13(15)18-11(9)20/h5,7-8H,3-4,6,14H2,1-2H3,(H3,15,17,18,20)/t8-/m0/s1 ; Key:HDOVUKNUBWVHOX-QMMMGPOBSA-N ;
	(what is this?) (verify)

Valaciclovir, also spelled valacyclovir, is an antiviral medication used to treat outbreaks of herpes simplex or herpes zoster (shingles). It is also used to prevent cytomegalovirus following a kidney transplant in high risk cases. It is taken by mouth.

Common side effects include headache and vomiting. Severe side effects may include kidney problems. Use in pregnancy appears to be safe. It is a prodrug, which works after being converted to aciclovir in a person's body.

Valaciclovir was patented in 1987 and came into medical use in 1995. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2022, it was the 113th most commonly prescribed medication in the United States, with more than 5 million prescriptions.