Zeffix Dosage/Direction for Use

Therapy with Zeffix should be initiated by a physician experienced in the management of chronic hepatitis B.
Adults: The recommended dosage of Zeffix is 100 mg once daily.
In patients with decompensated liver disease, lamivudine should always be used in combination with a second agent, without cross-resistance to lamivudine, to reduce the risk of resistance and to achieve rapid viral suppression.
Duration of Treatment: The optimal duration of treatment is unknown.
In patients with HBeAg positive chronic hepatitis B (CHB) without cirrhosis, treatment should be administered for at least 6-12 months after HBeAg seroconversion (HBeAg and HBV DNA loss with HBeAb detection) is confirmed, to limit the risk of virological relapse, or until HBsAg seroconversion or there is loss of efficacy (see Precautions). Serum ALT and HBV DNA levels should be followed regularly after treatment discontinuation to detect any late virological relapse.
In patients with HBeAg negative CHB (pre-core mutant) without cirrhosis, treatment should be administered at least until HBs seroconversion or there is evidence of loss of efficacy. With prolonged treatment, regular reassessment is recommended to confirm that continuation of the selected therapy remains appropriate for the patient.
In patients with decompensated liver disease or cirrhosis and in liver transplant recipients, treatment cessation is not recommended (see Pharmacology: Pharmacodynamics under Actions).
If lamivudine is discontinued, patients should be periodically monitored for evidence of recurrent hepatitis (see Precautions).
Clinical Resistance: In patients with either HBeAg positive or HBeAg negative CHB, the development of YMDD (tyrosine-methionine-aspartate-aspartate) mutant HBV may result in a diminished therapeutic response to lamivudine, indicated by a rise in HBV DNA and ALT from previous on-treatment levels. In order to reduce the risk of resistance in patients receiving lamivudine monotherapy, a modification of treatment should be considered if serum HBV DNA remains detectable at or beyond 24 weeks of treatment. In patients with YMDD mutant HBV, addition of an alternative agent without cross-resistance to lamivudine should be considered (see Pharmacology: Pharmacodynamics under Actions).
For the treatment of patients who are co-infected with HIV and are currently receiving or plan to receive treatment with lamivudine or the combination lamivudine-zidovudine, the dose of lamivudine prescribed for HIV infection (usually 150 mg/twice daily in combination with other antiretrovirals) should be maintained.
Special Populations: Renal Impairment: Lamivudine serum concentrations (AUC) are increased in patients with moderate to severe renal impairment due to decreased renal clearance. The dosage should, therefore, be reduced for patients with a creatinine clearance of <50 mL/minute (see Table 3).

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Data available in patients undergoing intermittent haemodialysis (for less than or equal to 4 hrs dialysis 2-3 times weekly), indicate that following the initial dosage reduction of lamivudine to correct for the patient’s creatinine clearance, no further dosage adjustments are required while undergoing dialysis.
Hepatic Impairment: Data obtained in patients with hepatic impairment, including those with end-stage liver disease awaiting transplant, show that lamivudine pharmacokinetics are not significantly affected by hepatic dysfunction. Based on these data, no dose adjustment is necessary in patients with hepatic impairment unless accompanied by renal impairment.
Elderly: In elderly patients, normal ageing with accompanying renal decline has no clinically significant effect on lamivudine exposure, except in patients with creatinine clearance of <50 mL/min.
Paediatric Population: The safety and efficacy of Zeffix in infants, children and adolescents aged below 18 years have not been established. Currently available data are described in Pharmacology: Pharmacodynamics under Actions and Precautions but no recommendation on a posology can be made.
Administration: Oral use. Zeffix can be taken with or without food.