Lamivudine
Mechanism :
Lamivudine is a synthetic nucleoside analogue. Intracellularly, lamivudine is phosphorylated to its active 5-triphosphate metabolite, lamivudine triphosphate (3TC-TP). The principal mode of action of 3TC-TP is the inhibition of HIV-1 reverse transcriptase (RT) via DNA chain termination after incorporation of the nucleotide analogue into viral DNA.
Indication :
- Combination with other antiretroviral agents is indicated for the treatment of HIV infection
- Chronic Hepatitis B
Contraindications :
Contraindicated in patients with previously demonstrated clinically significant hypersensitivity to any of the components of the products.
Dosing :
HIV:
Neonates (aged <4 weeks):
2 mg/kg orally twice daily.
≥1 month:
4 mg/kg orally every twice daily.
≥3 months:
5 mg/kg orally twice daily or 10 mg/kg orally daily; not to exceed 300 mg/day.
May switch to once daily dosing after age 3 years in clinically stable patients with undetectable viral load and stable CD4 count.
Chronic Hepatitis B:
>2 years:
3 mg/kg PO OD, Max: 100 mg/day.
Adverse Effect :
Shortness of breath, dizziness, severe vomiting or diarrhea, muscle aches, pains, or weakness, weight gain around waist and/or face, pain, tingling, or numbness in the hands or feet, central and peripheral neuropathy, bradycardia, arrhythmias, abdominal pain or discomfort, hyperglycemia, pancreatitis, worsening jaundice or other signs of hepatitis are common side effects.
Interaction :
Zalcitabine: May inhibit the intracellular phosphorylation of one another. Therefore, use of lamivudine in combination with zalcitabine is not recommended.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 30-50 | HIV: 150 mg daily. Hepatitis B: 100 mg stat then 50 mg daily |
| 15-30 | HIV: 150 mg stat then 100 mg daily. Hepatitis B: 100 mg stat then 25 mg daily |
| 5-15 | HIV: 150 mg stat then 50 mg daily. Hepatitis B: 35 mg stat then 15 mg daily |
| <5 | HIV: 150 mg stat then 25–50 mg daily. Hepatitis B: 35 mg stat then 10 mg daily |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<5 mL/min |
| HD | Dialysed. Dose as in GFR<5 mL/min |
| HDF/High flux | Dialysed. Dose as in GFR<5 mL/min |
| CAV/VVHD | Unknown dialysability. Dose as in GFR=5–15 mL/min |
Hepatic Dose :
No dose adjustments are recommended. Treatment should be discontinued if patient develops lactic acidosis or pronounced hepatotoxicity.