3TC

What it is

3TC (lamivudine) in combination with other antiretroviral agents is indicated for the treatment of HIV infected adults and children. Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI).

Approved indications

— HIV infection in adults and children, used in combination with other antiretroviral agents

Dosing overview

For adults, adolescents and children weighing at least 25 kg, the recommended dose of 3TC is 150 mg twice daily, or alternatively 300 mg once daily. For children aged greater than three months and weighing less than 25 kg using oral solution, the recommended dose is 0.5 mL/kg (5 mg/kg) twice daily or 1 mL/kg (10 mg/kg) once daily. For children weighing 14 to less than 20 kg using tablets, the recommended total daily dose is 150 mg, administered as either one-half of a 150 mg scored tablet (75 mg) twice daily or one whole 150 mg tablet once daily. In patients with moderate to severe renal impairment, lamivudine plasma concentrations are increased due to decreased clearance, and the dose should therefore be adjusted. In patients with moderate or severe hepatic impairment, lamivudine pharmacokinetics are not significantly affected by hepatic dysfunction, and no dose adjustment is necessary unless accompanied by renal impairment.

Key safety warnings

Lamivudine is not recommended for use as monotherapy. Pancreatitis has been observed in some patients receiving lamivudine, though it is unclear whether this was due to treatment or the underlying HIV disease. Pancreatitis must be considered whenever a patient develops abdominal pain, nausea, vomiting or elevated biochemical markers, and lamivudine should be discontinued until diagnosis is excluded. Some patients with chronic hepatitis B virus (HBV) disease may experience clinical or laboratory evidence of recurrent hepatitis upon discontinuation of lamivudine. If lamivudine is discontinued in a patient with HIV and HBV coinfection, periodic monitoring of both liver function tests and markers of HBV replication should be considered. Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with lamivudine use. Clinical features may include generalised weakness, anorexia, sudden unexplained weight loss, gastrointestinal and respiratory symptoms. Treatment should be suspended in any patient who develops clinical or laboratory findings suggestive of lactic acidosis. In HIV-infected patients with severe immune deficiency at the time of initiation of antiretroviral therapy, an inflammatory reaction to asymptomatic or residual opportunistic infections may arise, typically within the first few weeks or months of treatment initiation. Any inflammatory symptoms must be evaluated without delay and treatment initiated when necessary.

Contraindications

Lamivudine is contraindicated in patients with known hypersensitivity to lamivudine or to any ingredient of the preparation.

PBS listing

The 300 mg tablet is listed on the PBS with streamlined authority required status at an ex-manufacturer price of A$44.26. The 150 mg tablet is also listed with streamlined authority required status at an ex-manufacturer price of A$44.26. The oral solution 10 mg per mL (240 mL) is listed with streamlined authority required status at an ex-manufacturer price of A$55.98.

Regulatory history

The 150 mg tablet formulation (ARTG 54313) was first registered on 13 March 1996. The oral solution 10 mg/mL (ARTG 64346) was first registered on 9 June 1998. The 300 mg tablet formulation (ARTG 81359) was first registered on 18 January 2002.