Nurses Compass
Drug Guide
Abacavir Sulfate and Lamivudine
Classification
Therapeutic: Antiretroviral (HIV-1 treatment)
Pharmacological: Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
FDA Approved Indications
- Treatment of HIV-1 infection in combination with other antiretroviral agents
Mechanism of Action
Abacavir inhibits HIV-1 reverse transcriptase by incorporating into viral DNA, causing chain termination. Lamivudine also inhibits reverse transcriptase by causing DNA chain termination; together, they inhibit HIV replication.
Dosage and Administration
Adult: 300 mg of abacavir plus 300 mg of lamivudine once daily or in divided doses twice daily, as part of combination therapy.
Pediatric: Dose based on body weight, typically 8 mg/kg of abacavir and 4 mg/kg of lamivudine twice daily, with a maximum dose of 300 mg for each drug per dose.
Geriatric: Use with caution due to potential comorbidities and drug interactions; no specific dose adjustment, but renal and hepatic function should be considered.
Renal Impairment: Adjust dose according to renal function; generally, use with caution and monitor renal function.
Hepatic Impairment: Use with caution; dose adjustment may be necessary, especially in severe hepatic impairment.
Pharmacokinetics
Absorption: Rapidly absorbed orally.
Distribution: Widely distributed in body tissues.
Metabolism: Lamivudine minimally metabolized; abacavir metabolized in the liver via alcohol dehydrogenase.
Excretion: Primarily renally excreted for both drugs.
Half Life: Abacavir approximately 2.4 hours; lamivudine approximately 5-7 hours.
Contraindications
- Hypersensitivity to abacavir or lamivudine.
- HLA-B*5701 positive status (due to hypersensitivity risk).
Precautions
- History of hypersensitivity reactions; hepatic or renal impairment; lactic acidosis risk.
Adverse Reactions - Common
- Nausea (Common)
- Headache (Common)
- Fatigue (Common)
Adverse Reactions - Serious
- Hypersensitivity reactions (Rare)
- Lactic acidosis (Rare)
- Hepatotoxicity (Rare)
Drug-Drug Interactions
- Abacavir and lamivudine may interact with other drugs affecting the liver or renal function.
- Use caution with drugs affecting CYP450 enzymes.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for signs of hypersensitivity, adverse reactions, and efficacy of therapy.
Diagnoses:
- Risk for ineffective tissue perfusion
- Risk for injury due to hypersensitivity.
Implementation: Administer as prescribed, monitor labs regularly including liver and renal function.
Evaluation: Assess viral load and immune status to determine treatment efficacy.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report any hypersensitivity symptoms immediately.
- Adhere to follow-up lab testing and doctor's appointments.
Special Considerations
Black Box Warnings:
- Severe hypersensitivity reactions associated with HLA-B*5701 allele.
- Lactic acidosis and hepatomegaly with steatosis.
Genetic Factors: Testing for HLA-B*5701 allele recommended before starting therapy.
Lab Test Interference: May affect certain lab tests; inform laboratory personnel.
Overdose Management
Signs/Symptoms: Potential for severe hypersensitivity or lactic acidosis.
Treatment: Supportive care; no specific antidote. Immediate medical attention required.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable under recommended storage conditions.