Therapeutic Classification: antiretrovirals, antivirals
Pharmacologic Classification: nucleoside reverse transcriptase inhibitors
Absorption: Well absorbed after oral administration (86% in adults, 66% in infants and children).
Distribution: Distributes into the extravascular space. Some penetration into CSF; remainder of distribution unknown.
Metabolism/Excretion: Mostly excreted unchanged in urine; <5% metabolized by the liver.
Half-life: Epivir: 57 hr; Epivir HBV: 1319 hr.
(blood levels)
On an empty stomach; peak levels occur at 3.2 hr if lamivudine is taken with food. Food does not affect total amount of drug absorbed.
Contraindicated in:
- Hypersensitivity
- Concurrent use of antiretroviral combination products containing lamivudine or emtricitabine
- Lactation: Breastfeeding not recommended for mothers with HIV.
Use Cautiously in:
- Renal impairment (↑ dosing interval/↓ dose if CCr <50 mL/min)
- Women and obesity (↑ risk of lactic acidosis and severe hepatomegaly with steatosis)
- Coinfection with HBV (hepatitis may recur after discontinuation of lamivudine; Epivir HBV is not indicated for treatment of HIV because lamivudine dosage is subtherapeutic)
- OB: Considered a preferred nucleoside reverse transcriptase inhibitor (NRTI) for pregnant patients with HIV infection who are antiretroviral-nave, who have had antiretroviral therapy in the past but are restarting, or who require a new antiretroviral regimen; use has also been studied in pregnant women with HBV
- Pedi: Safety and effectiveness not established in children <3 mo (HIV) or <2 yr (HBV)
- Geri: ↓dose may be necessary in older adults due to age-related ↓ in renal function.
Exercise Extreme Caution in:
- Pedi: Pediatric patients with a history of or significant risk factors for pancreatitis (use only if no alternative).
Derm: alopecia, erythema multiforme, rash, urticaria.
Endo: hyperglycemia.
F and E: lactic acidosis.
GI: anorexia, diarrhea, nausea, vomiting, ↑ liver enzymes, abdominal discomfort, dyspepsia, HEPATOMEGALY WITH STEATOSIS, PANCREATITIS (↑ IN PEDIATRIC PATIENTS).
Hemat: anemia, neutropenia, pure red cell aplasia.
MS: musculoskeletal pain, arthralgia, muscle weakness, myalgia, rhabdomyolysis.
Neuro: fatigue, headache, insomnia, malaise, neuropathy, depression, dizziness, SEIZURES.
Resp: cough.
Misc: (INCLUDING ANAPHYLAXIS)HYPERSENSITIVITY REACTIONS , immune reconstitution syndrome.
HIV1 Infection (Epivir)
- PO (Adults): 150 mg twice daily or 300 mg once daily.
- PO (Children 3 mo): Oral solution: 5 mg/kg twice daily or 10 mg/kg once daily (max dose = 300 mg/day); Tablets: 1419 kg: 75 mg twice daily or 150 mg once daily; 2024 kg: 75 mg in AM, 150 mg in PM or 225 mg once daily; 25 kg: 150 mg twice daily or 300 mg once daily.
Renal Impairment
- (Adults and Children 25 kg): CCr 3049 mL/min: 150 mg once daily; CCr 1529 mL/min: 150 mg initially, then 100 mg once daily; CCr 514 mL/min: 150 mg initially, then 50 mg once daily; CCr <5 mL/min: 50 mg initially, then 25 mg once daily.
Chronic Hepatitis B (Epivir HBV)
- PO (Adults): 100 mg once daily.
- PO (Children 217 yr): 3 mg/kg once daily (up to 100 mg/day).
Renal Impairment
- PO (Adults): CCr 3049 mL/min: 100 mg first dose, then 50 mg once daily; CCr 1529 mL/min: 100 mg first dose, then 25 mg once daily; CCr 514 mL/min: 35 mg first dose, then 15 mg once daily; CCr <5 mL/min: 35 mg first dose, then 10 mg once daily.