[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Hepatitis B antivirals](https://durgical.com/en/pharmacology/classes/hepatitis-b-antivirals/) › Adefovir

# Adefovir

## Hepatitis B antivirals?

Hepatitis B antivirals

## Pregnancy: avoid?

Not used in pregnancy, and breastfeeding is avoided; other hepatitis B drugs are preferred.

An older oral nucleotide analogue for chronic hepatitis B. Kidney toxicity and resistance mean that entecavir or tenofovir are preferred today.

Updated Nov 1, 2026

Also called: Adefovir dipivoxil

## Quick facts

**Group**
[Hepatitis B antivirals](https://durgical.com/en/pharmacology/classes/hepatitis-b-antivirals/)

**Target**
HBV polymerase (reverse transcriptase)

**Used for**
Chronic hepatitis B in adults

**Key effects**
Weakness · Headache · Diarrhoea

**Monitor**
Serum creatinine and phosphate · HBV DNA

**ATC**
J05AF08

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Adefovir dipivoxil is a prodrug that is de-esterified to adefovir, an acyclic phosphonate analogue of adenosine monophosphate. Cell enzymes add two phosphates; adefovir diphosphate competes with deoxyadenosine triphosphate at the HBV polymerase (a reverse transcriptase) and ends the viral DNA chain. Resistance builds up over years of use.

- The prodrug releases adefovir
- Cell kinases form adefovir diphosphate
- It competes with dATP at the HBV polymerase
- Viral DNA chain synthesis stops

## Indications

- Chronic hepatitis B in adults and children twelve years and older (no longer a preferred agent) [Viral hepatitis →](https://durgical.com/en/conditions/viral-hepatitis/)

## Adverse effects

### Common

- Weakness
- Headache
- Diarrhoea, gas and indigestion
- Sore throat and runny nose

### Serious (rare, important)

- Kidney tubular damage (raised creatinine, low phosphate, glycosuria, proteinuria)
- Severe flare of hepatitis after stopping
- Lactic acidosis with liver enlargement and fat
- HIV resistance if untreated HIV is present

## Contraindications

- Hypersensitivity to adefovir
- Use alone in untreated HIV infection (risk of HIV resistance)

## Key interactions

**Nephrotoxic drugs (aminoglycosides, NSAIDs, ciclosporin, tacrolimus, vancomycin)**
Higher risk of kidney damage

**Drugs that compete for renal tubular secretion**
May raise adefovir levels

**Other nucleoside analogues**
Possible higher risk of lactic acidosis

## What is monitored

- Serum creatinine and phosphate
- HBV DNA (resistance)
- Liver tests during and for months after stopping
- HIV test before starting

## Administration and safety

- Oral, once daily, with or without food
- Doses are not missed and the drug is not stopped without the team

## Pregnancy and breastfeeding

Not used in pregnancy, and breastfeeding is avoided; other hepatitis B drugs are preferred.

## Nursing care

- Check HIV status and kidney function before starting
- Teach not to stop suddenly: hepatitis can flare
- Teach to report less urine, swelling, or yellow skin
- Ask about painkillers such as NSAIDs

## Pharmacokinetics

**Absorption**
Oral prodrug, with or without food

**Metabolism**
Hydrolysed to adefovir by esterases in the gut, liver and blood

**Elimination**
Unchanged by the kidneys (filtration and tubular secretion via OAT1); adjusted in kidney disease

## Memory aid

A-DE-FOvir: A for Adenine, DE for «deteriorating kidneys»: the reason it is no longer first line.

## Test yourself

Think of the answer, then tap the question to see it.

## Adefovir is an analogue of which nucleotide?

Adenosine monophosphate (an acyclic phosphonate).

## What is the main toxicity of adefovir?

Kidney tubular damage, with raised creatinine and low phosphate.

## Why is adefovir no longer preferred for hepatitis B?

Resistance develops over years and it is nephrotoxic; entecavir and tenofovir are better.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/adefovir/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**Pregnancy: avoid**
Not used in pregnancy, and breastfeeding is avoided; other hepatitis B drugs are preferred.

## Connections

## Related drugs 3

- [Entecavir](https://durgical.com/en/pharmacology/entecavir/)
- [Tenofovir disoproxil](https://durgical.com/en/pharmacology/tenofovir-disoproxil/)
- [Lamivudine](https://durgical.com/en/pharmacology/lamivudine/)

## Related conditions 1

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)

[← Back to the class: Hepatitis B antivirals](https://durgical.com/en/pharmacology/classes/hepatitis-b-antivirals/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Adefovir: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a605024.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=J05AF08) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/adefovir/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/adefovir/