Common adverse reactions of lamivudine that can be confused with an acute porphyric attack are nausea, vomiting, abdominal pain and diarrhoea. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

Lamivudine is not metabolized by CYP450 enzymes, and is not an inducer or a mechanism-based inhibitor of CYP450 enzymes. No pharmacokinetic porphyrinogenic effects are suspected.

Nucleoside analogue

Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) used in the treatment of HIV-1 and hepatitis B. It is administered orally.

Lamivudine is not a substrate, inhibitor or inducer of CYP450 enzymes (Johnson 1999, SPC). The majority of lamivudine is eliminated unchanged through the kidney, and only 5 % is metabolized to trans-sulfoxide (Kumar 2010).