Patients who are HIV-positive, co-infected with hepatitis B virus and are receiving treatment with lamivudine in combination with other antiretroviral agents for HIV, should continue treatment with the regimen prescribed for HIV infection (150 mg twice daily). These patients are also at risk of an exacerbation of their hepatitis if their lamivudine treatment for HIV is discontinued.
The clinical and virological status of patients should be monitored regularly during treatment by a physician experienced in the management of hepatitis B infection.
There is no information available on maternal-fetal transmission of hepatitis B virus in pregnant mothers receiving treatment with 3TC-HBV. The standard recommended procedures for hepatitis B virus immunization in infants should still be followed.
Patients should be advised that therapy with 3TC-HBV has not been proven to prevent the risk of transmission of hepatitis B virus to others, through sexual contact or blood contamination. Appropriate precautions should still be taken.
The efficacy of lamivudine in hepatitis B patients co-infected with hepatitis C and D is unknown.
Effects on the Ability to Drive or Operate Machinery: There have been no studies to investigate the effect of lamivudine on driving performance or the ability to operate machinery. Further, a detrimental effect on such activities would not be predicted from the pharmacology of the drug. Nevertheless, the clinical status of the patient and the adverse event profile of 3TC-HBV should be borne in mind when considering the patient's ability to drive or operate machinery.
Use in pregnancy & lactation: Reproductive studies in animals have not shown evidence of teratogenicity and showed no effect on male or female fertility. There was some evidence of early embryo lethality when administered to pregnant rabbits at exposure levels of 2 or 3 times those achieved in humans at therapeutic doses. Studies in lactating rats showed that following oral administration, levels of lamivudine in milk were generally higher than those measured in plasma.
Although animal reproductive studies are not always predictive of the human response, lamivudine should be used during pregnancy only if the potential benefits outweigh the risks. Administration of 3TC-HBV during the first 3 months of pregnancy is not recommended.
In clinical study, lamivudine has proven to be safe and well tolerated in HIV-infected pregnant women at doses up to 300 mg twice daily, administered from week 38 of pregnancy.
Lamivudine was shown to cross the placenta with a maternal/neonate serum concentration ratio of about 1 established at birth. The presence of lamivudine in amniotic fluid was also established.
There is no safety information available on infant breastfed by mothers treated with 3TC-HBV. In breast milk samples taken in the 1st week postpartum, lamivudine was present overall in similar concentrations to those seen in serum (range 1-8 mcg/mL). Ingestion of lamivudine via this route would not provide concentrations sufficient to provide antiviral (HBV) protection.
Breastfeeding should not be discouraged unless the potential risk to the baby is considered to outweigh the benefit of treatment with lamivudine to the mother.