Stiripentol

How it works

It enhances GABAergic neurotransmission by acting at GABA-A receptors and also inhibits several cytochrome P450 enzymes, raising the plasma concentrations of co-administered antiseizure medicines.

Prescribing in practice

• It is a potent inhibitor of CYP enzymes and markedly raises levels of clobazam and valproate, so the doses of these co-medicines usually need reducing to manage drowsiness and other concentration-dependent effects.
• It is licensed only as add-on therapy alongside clobazam and valproate, not as monotherapy.
• Slowed thinking, ataxia and appetite loss are common and may necessitate adjustment of the overall regimen.

Monitoring

Monitor growth and neutrophil and platelet counts, watch for sedation, and consider plasma levels of co-administered antiseizure drugs given the interaction burden.

Counselling the patient

• Take it with food and never stop suddenly, as abrupt withdrawal can provoke seizures.
• Report excessive drowsiness, unsteadiness or poor appetite, as the dose of other epilepsy medicines may need adjusting.

Evidence & guidelines

Use in Dravet syndrome is supported by the STICLO randomised controlled trials and reflected in its orphan-drug licensing for this indication.