Adefovir

Name: Adefovir

What other information should I know?

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Pharmacology

Mechanism of Action

Acyclic nucleotide analog; inhibits HBV DNA polymerase; inhibition blocks reverse transcriptase activity, which in turn reduces viral DNA synthesis

Absorption

Bioavailability: 59%

Peak plasma time: 0.58-4 hr

Peak plasma concentration: 18.4±6.26 ng/mL

AUC: 220±70 ng•hr/mL

Distribution

Protein Bound: ≤ 4%

Vd: 317-467 mL/kg

Metabolism

Rapidily converted to adefovir from the diester prodrug, adefovir dipivoxil

Metabolites: Adefovir (active)

Elimination

Half-life: 7.48±1.65 hr

Renal clearance: 231±48.9 mL/min

Excretion: Urine; renal glomerular filtration, active tubular secretion

Dialyzable: Yes

How should I take adefovir?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Take adefovir with a full glass of water. Adefovir may be taken with or without food.

Use this medicine regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely. You should not stop using adefovir without your doctor's advice.

While using adefovir, you may need frequent blood tests. Your kidney or liver function may also need to be checked. You must remain under the care of a doctor while you are using adefovir. Visit your doctor regularly.

Store at room temperature away from moisture and heat.

You may develop liver symptoms after you stop taking this medication. Your doctor may want to check your liver function for several months after you stop using adefovir.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Uses of Adefovir

  • It is used to treat hepatitis B infection.

Pronunciation

(a DEF o veer)

Index Terms

  • Adefovir Dipivoxil
  • Bis-POM PMEA

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral, as dipivoxil:

Hepsera: 10 mg

Generic: 10 mg

Special Populations Renal Function Impairment

Cmax and AUC increased in those with moderate or severe renal function impairment or with end-stage renal disease.

Use Labeled Indications

Treatment of chronic hepatitis B with evidence of active viral replication (based on persistent elevation of ALT/AST or histologic evidence)

Dosing Pediatric

Hepatitis B (chronic): Children ≥12 years: Oral: 10 mg once daily

Adverse Reactions

In liver transplant patients with baseline renal dysfunction, frequency of increased serum creatinine has been observed to be as high as 32% to 51% at 48 and 96 weeks post-transplantation, respectively; considering the concomitant use of other potentially nephrotoxic medications, baseline renal insufficiency, and predisposing comorbidities, the role of adefovir in these changes could not be established.

>10%:

Central nervous system: Headache (24% to 25%)

Gastrointestinal: Abdominal pain (15%), diarrhea (≤13%)

Genitourinary: Hematuria (grade ≥3: 11%)

Hepatic: Hepatitis (exacerbation; ≤25% within 12 weeks of adefovir discontinuation)

Neuromuscular & skeletal: Weakness (≤25%)

1% to 10%:

Dermatologic: Pruritus, skin rash

Endocrine & metabolic: Hypophosphatemia (<2 mg/dL: 1% and 3% in pre-/post-liver transplant patients, respectively)

Gastrointestinal: Flatulence (≤8%), dyspepsia (5% to 9%), nausea, vomiting

Neuromuscular & skeletal: Back pain (≤10%)

Renal: Increased serum creatinine (≥0.5 mg/dL: 2% to 3% in compensated liver disease; incidence may be higher in patients with decompensated cirrhosis or in liver transplant recipients), renal failure

Respiratory: Cough (6% to 8%), rhinitis (≤5%)

<1% (Limited to important or life-threatening): Fanconi's syndrome, hepatitis, myopathy, nephrotoxicity, osteomalacia, pancreatitis, proximal tubular nephropathy

Adefovir Levels and Effects while Breastfeeding

Summary of Use during Lactation

Adefovir has not been studied in nursing mothers being treated for hepatitis B infection. An alternate drug may be preferred, especially while nursing a newborn or preterm infant.

No differences exist in infection rates between breastfed and formula-fed infants born to hepatitis B-infected women, as long as the infant receives hepatitis B immune globulin and hepatitis B vaccine at birth. Mothers with hepatitis B are encouraged to breastfeed their infants after their infants receive these preventative measures.[1][2]

Drug Levels

Maternal Levels. Relevant published information was not found as of the revision date.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider

(Hepatitis B) Interferon Alfa, Lamivudine, Tenofovir

References

1. Visvanathan K, Dusheiko G, Giles M et al. Managing HBV in pregnancy. Prevention, prophylaxis, treatment and follow-up: Position paper produced by Australian, UK and New Zealand key opinion leaders. Gut. 2016;65:340-50. PMID: 26475631

2. Dionne-Odom J, Tita AT, Silverman NS. #38: Hepatitis B in pregnancy screening, treatment, and prevention of vertical transmission. Am J Obstet Gynecol. 2016;214:6-14. PMID: 26454123

Adefovir Identification

Substance Name

Adefovir

CAS Registry Number

106941-25-7

Drug Class

Antiviral Agents

Anti-Retroviral Agents

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