Raltegravir does not inhibit or induce CYP enzymes. Side effects such as nausea, vomiting and diarrhoea may be potentially porphyrinogenic through reduction in carbohydrate intake.

Raltegravir is indicated in combination with other anti-retroviral medicinial products for the treatment of human immunodeficiency virus (HIV-1) infection in adults. Common reported side effects that can be confused with an acute porphyria attack are abdominal pain, diarrhoea, nausea and vomiting. Other common side effects are insomnia.

In vitro and in vivo studies have shown that raltregravir is mainly metabolised via a UGT1A1 mediated glucuronidation pathway (SPC, Zhang 2010). The elimination half-life is 9 hours. In vitro-studies indicates that raltegravir is not a substrate of CYP450 enzymes. It does not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 nor does it induce CYP3A4 (SPC). An in vivo study has shown that raltegravir does not affect the plasma level of midazolam, a sensitive probe CYP3A4 substrate. This indicates that it does not induce or inhibit CYP3A4 (Iwamoto 2008).