Sumatriptan is not a substrate of CYP3A4 or any other major CYP enzymes. It is not an inhibitor or and inducer of CYP3A4. Risk for gastrointestinal adverse events in the form of nausea and vomiting motivates vigilance against insufficient intake of food, especially of carbohydrate.

Sumatriptan is a serotonin-receptor agonist.

Sumatriptan is indicated for the acute relief of migraine attacks, with or without aura, and for the acute treatment of cluster headache. Common side effects that can be potentially porphyrinogenic through reduction in carbohydrate intake and that also can be confused with an acute porphyria attack are nausea and vomiting. It is however unclear whether the side effects are related to sumatriptan or the underlying condition.

Sumatriptan is metabolised via oxidative metabolism by monoamine oxidase A (SPC). The major metabolite is the indole acetic acid analogue which is excreted in the urine. A clinical study showed that sumatriptan is unaffected by co-administration with clarithromycin, a CYP3A4 inhibitor (Moore 2002). This confirms that sumatriptan is not a substrate of CYP3A4. Co-administration of sumatriptan with oral contraceptives, norethindrone and ethinyl estradiol (CYP3A4 substrates), did not change the AUC of any of medications compared with administration alone (Moore 2002). These data indicates that sumatriptan is not an inducer or an inhibitor of CYP3A4.

Thunell: patient inquiry: tolerated (n=1) Andersson; patient inquiry: used without ill effects (n=2)

Uneventful use reported in 5 patients with acute porphyria.