Telbivudine

• Approved Indications:
• Treatment of chronic hepatitis B virus (HBV) infection in adults with active viral replication and evidence of liver inflammation (elevated ALT/AST or histologic disease).
• Patients with compensated liver disease due to chronic HBV infection.
• Off-label Uses:
• May be used in some cases of lamivudine-resistant HBV infection under specialist supervision.
• Occasionally considered in combination regimens for enhanced antiviral efficacy.

• Adults:
• Oral dose: 600 mg once daily, with or without food.
• Duration individualized based on viral response; often continued for at least 1 year.
• Pediatrics:
• Safety and efficacy not established for patients under 16 years.
• Elderly:
• No specific dose adjustment; renal function monitoring recommended.
• Renal Impairment:
• For creatinine clearance <50 mL/min, dose adjustment necessary.
• Hemodialysis patients: 400 mg every 48 hours or after each dialysis session.
• Administration:
• Taken orally once daily at the same time each day.
• Food intake does not affect bioavailability.

Telbivudine is a synthetic thymidine nucleoside analogue that inhibits HBV DNA polymerase. Inside infected hepatocytes, it is phosphorylated to its active triphosphate form, which competes with natural thymidine triphosphate for incorporation into viral DNA. This leads to premature DNA chain termination, effectively blocking viral replication and reducing viral load.

• Absorption: Rapid, peak plasma concentration 1.3–3 hours post-dose.
• Bioavailability: Approximately 85%.
• Distribution: Volume of distribution ~0.6 L/kg; minimal plasma protein binding.
• Metabolism: Minimal; primarily excreted unchanged.
• Half-life: Terminal half-life ranges 14–40 hours.
• Elimination: Mainly renal clearance of unchanged drug.

• Pregnancy: FDA Category B — animal studies show no fetal risk, but human data are limited. Use only if benefits justify potential risks.
• Lactation: Unknown if excreted in human milk; caution advised during breastfeeding.

• Antiviral agent, nucleoside analogue reverse transcriptase inhibitor (NRTI).

• Known hypersensitivity to telbivudine or any formulation component.
• Severe renal impairment without proper dose adjustment.
• Concurrent use with other nucleoside analogues without specialist oversight.

• Monitor for development of HBV resistance.
• Watch for signs of myopathy and peripheral neuropathy.
• Rare risk of lactic acidosis and hepatomegaly with steatosis.
• Adjust dose and monitor renal function in renal impairment.
• Discontinuation may cause HBV exacerbation; monitor liver function closely.
• Regular liver function monitoring required.

• Common:
• Headache, fatigue, nausea, diarrhea.
• Elevated creatine kinase.
• Serious/Rare:
• Peripheral neuropathy (numbness, tingling).
• Myopathy.
• Lactic acidosis.
• Severe hepatomegaly with steatosis.
• Hypersensitivity reactions.

• No significant CYP450 interactions.
• Caution with other nephrotoxic agents.
• Potential additive myopathy risk with drugs like statins.
• No significant food or alcohol interactions.

• Reinforced importance of renal dose adjustments.
• Emphasis on resistance monitoring during prolonged therapy.
• Continues to be recommended for chronic HBV treatment with active disease.
• No new black box warnings.

• Store at 20°C to 25°C.
• Protect from moisture and light.
• Keep tightly closed and out of reach of children.
• No refrigeration required.