Lamivudine + Abacavir

Indications

Lamivudine + Abacavir is used for: HIV infection

Adult Dose

Oral HIV infection Adult: Each tab contains abacavir 600 mg and lamivudine 300 mg: 1 tab once daily. Hepatic Impairment Contraindicated.

Child Dose

HIV Infection Indicated to treat HIV infection in combination with other antiretroviral drugs <25 kg: Safety and efficacy not established >25 kg: 1 tablet (300 mg lamivudine / 600 mg abacavir/) PO qDay Assess child's ability to swallow the tablet whole

Renal Dose

Renal Impairment CrCl <50 mL/min: Not recommended.

Administration

May be taken with or without food.

Contra Indications

Patients who have the HLA-B*5701 allele Prior hypersensitivity to abacavir or lamivudine Moderate or severe hepatic impairment

Precautions

Patients w/ coronary heart disease, chronic hepatitis B or C, renal impairment CrCl <50 mL/min. May exacerbate hepatitis B. Prior to treatment, screening for carriage of HLA-B*5701 should be done. Pregnancy. Monitor hepatic function, amylase bilirubin, blood glucose, serum creatinine kinase, haematologic parameters and triglycerides. Closely monitor for hypersensitivity reactions. Periodic LFT and markers for HBV is recommended in patients co-infected w/ hepatitis B as withdrawal of treatment may result in acute exacerbation of hepatitis.

Pregnancy-Lactation

Pregnancy Available data from antiretroviral pregnancy registry show no difference in overall risk of birth defects for abacavir or lamivudine compared with background rate for birth defects of 2.7% in Metropolitan Atlanta Congenital Defects Program (MACDP) reference population Lactation Abacavir and lamivudine are present in human milk; there is no information on effects of abacavir and lamivudine on breastfed infant or effects of drug on milk production; because of potential for (1) HIV-1 transmission (in HIV-negative infants), (2) developing viral resistance (in HIV-positive infants), and (3) serious adverse reactions in breastfed infant, instruct mothers not to breastfeed if they are receiving therapy

Interactions

Increased hepatic decompensation w/ interferon alfa. May increase the adverse effects of emtricitabine or emtricitabine-containing products. Bioavailability may decrease w/ methadone. Co-trimoxazole may increase the serum levels of lamivudine. Ribavirin may increase the risk of hepatotoxicity.

Adverse Effects

Side effects of Lamivudine + Abacavir : Lipodystrophy, immune reactivation syndrome, osteonecrosis. Anorexia, headache, insomnia, nausea, vomiting, abdominal pain or cramps, diarrhoea, rash, urticaria, alopecia, arthralgia, peripheral neuropathy, muscle disorders, fever, fatigue, lethargy, cough, nasal symptoms, increased CPK. Potentially Fatal: Severe hypersensitivity reactions, lactic acidosis, hepatic impairment (e.g. hepatomegaly), severe acute exacerbation of hepatitis B.

Mechanism of Action

Abacavir and lamivudine are both nucleoside reverse transcriptase inhibitors. Converted to their respective active triphosphate form, they have additive effect in inhibiting replication of retroviruses by interfering w/ viral RNA-directed DNA polymerase (reverse transcriptase).