Adefovir is a prescription medicine used to treat (chronic) infections with hepatitis B virus. A prodrug form of adefovir was previously called bis-POM PMEA, with trade names Preveon and Hepsera. It is an orally administered nucleotide analog reverse-transcriptase inhibitor (ntRTI). It can be formulated as the pivoxil prodrug adefovir dipivoxil.

Quick Facts Clinical data, Trade names ...

Adefovir

Clinical data
Trade names	Hepsera
AHFS/Drugs.com	Monograph
Pregnancy category	AU: B3
Routes of administration	Oral
ATC code	J05AF08 (WHO)
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	59%
Protein binding	<4%
Elimination half-life	7.5 hours
Excretion	Urine
Identifiers
IUPAC name {[2-(6-amino-9H-purin-9-yl)ethoxy]methyl}phosphonic acid
CAS Number	106941-25-7 N
PubChem CID	60172
DrugBank	DB00718 Y
ChemSpider	54252 Y
UNII	6GQP90I798
KEGG	D02768 Y
ChEBI	CHEBI:2469 Y
ChEMBL	ChEMBL484 Y
NIAID ChemDB	028595
CompTox Dashboard (EPA)	DTXSID6046214
ECHA InfoCard	100.106.235
Chemical and physical data
Formula	C8H12N5O4P
Molar mass	273.189 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=P(O)(O)COCCn1c2ncnc(c2nc1)N
InChI InChI=1S/C8H12N5O4P/c9-7-6-8(11-3-10-7)13(4-12-6)1-2-17-5-18(14,15)16/h3-4H,1-2,5H2,(H2,9,10,11)(H2,14,15,16) Y Key:SUPKOOSCJHTBAH-UHFFFAOYSA-N Y
NY (what is this?)  (verify)

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It is used for treatment of hepatitis B.^[1][2][3][4]

Trials of adefovir in patients with HIV have not shown any clear benefits.^[3][5]

Adefovir was invented in the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic by Antonín Holý, and the drug was developed by Gilead Sciences for HIV with the brand name Preveon. However, in November 1999, an expert panel advised the U.S. Food and Drug Administration (FDA) not to approve the drug due to concerns about the severity and frequency of kidney toxicity when dosed at 60 or 120 mg. The FDA followed that advice, refusing to approve adefovir as a treatment for HIV.^{[citation needed]}

Gilead Sciences discontinued its development for HIV treatment in December 1999, but continued to develop the drug for hepatitis B (HBV), where it is effective with a much lower dose of 10 mg. FDA approval for use in the treatment of hepatitis B was granted on September 20, 2002, and adefovir is sold for this indication under the brand name Hepsera. Adefovir became an approved treatment for HBV in the European Union in March 2003.^{[citation needed]}

Adefovir works by blocking reverse transcriptase, an enzyme crucial for the HBV to reproduce in the body. It is approved for the treatment of chronic hepatitis B in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (primarily ALT) or histologically active disease.

The main benefit of adefovir over lamivudine (the first NRTI approved for the treatment of HBV) is that it takes a much longer period of time for the virus to develop resistance to it.

Adefovir dipivoxil contains two pivaloyloxymethyl units, making it a prodrug form of adefovir.