Adefovir Dipivoxil is indicated for the treatment of chronic hepatitis B in adults with active viral replication and either persistently elevated serum aminotransferases (ALT or AST) or histologically active liver disease.

Adefovir dipivoxil is a diester prodrug of adefovir. Adefovir is an acyclic nucleotide analogue active against human hepatitis B virus (HBV). Inside cells, adefovir is phosphorylated to its active form, adefovir diphosphate. This active form inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate deoxyadenosine triphosphate and terminating viral DNA chains. Oral bioavailability from a 10 mg single dose is approximately 59%. Binding to human plasma proteins is 4%. Adefovir is excreted via the kidneys by glomerular filtration and active tubular secretion.

The recommended dose of Adefovir in chronic hepatitis B patients with adequate renal function is 10 mg, once daily, taken orally, without regard to food.

The pharmacokinetics of Adefovir remain unchanged when co-administered with Lamivudine, Trimethoprim/Sulfamethoxazole, or Acetaminophen. However, when taken with Ibuprofen (800 mg three times daily), increases in Adefovir Cmax (33%), AUC (23%), and urinary excretion were observed due to higher oral bioavailability.

Adefovir Dipivoxil should not be used in patients with known hypersensitivity to any component of the product.

The most common side effects are weakness, headache, stomach pain, and nausea. Severe hepatitis flare-ups have been reported in patients who stop anti-hepatitis B therapy, including Adefovir Dipivoxil. In patients with or at risk of kidney problems, long-term use may cause nephrotoxicity. Rarely, lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with nucleoside analogues alone or in combination with other antiretrovirals.

Pregnancy Category C. There are no well-controlled studies in pregnant women. Adefovir Dipivoxil should only be used during pregnancy if clearly needed, after careful risk-benefit evaluation. It is unknown whether Adefovir passes into human milk. Mothers taking Adefovir Dipivoxil should not breastfeed.

Patients who discontinue Adefovir Dipivoxil should be monitored periodically for liver function. Patients at risk of or with kidney problems should have renal function monitored closely, and dose adjustment may be necessary.

Pediatric: Safety and effectiveness in children have not been established.
Geriatric: Exercise caution when prescribing to elderly patients due to higher risk of kidney or heart problems.

Dose Adjustment in Renal Impairment:

• CrCl ≥ 50 ml/min: 10 mg daily
• CrCl 20-49 ml/min: 10 mg every 48 hours
• CrCl 10-19 ml/min: 10 mg every 72 hours
• Hemodialysis patients: 10 mg every 7 days after dialysis

High doses, such as 500 mg daily for 2 weeks or 250 mg daily for 12 weeks, have been associated with gastrointestinal side effects. If overdose occurs, patients should be monitored for toxicity and receive supportive care as needed.

Hepatic viral infections (Hepatitis B)

Store in a cool, dry place. Protect from light and moisture. Keep all medicines out of the reach of children.