Modafinil

How it works

Its precise mechanism is not fully established, but it promotes wakefulness through actions on central monoaminergic systems, including inhibition of dopamine reuptake.

Prescribing in practice

• Modafinil can cause serious skin and hypersensitivity reactions including Stevens-Johnson syndrome, so it must be stopped at the first sign of rash and the patient assessed urgently.
• Because of risks in pregnancy, it should not be used in pregnancy and effective non-hormonal or additional contraception is required, as modafinil can reduce the effectiveness of hormonal contraceptives.
• Its use has been restricted by the regulator largely to narcolepsy because of cardiovascular and psychiatric risks, and blood pressure and heart rate should be assessed before and during treatment.

Monitoring

Monitor blood pressure and heart rate, and review for rash, mood changes or psychiatric symptoms during treatment.

Counselling the patient

• Stop the medicine and seek urgent advice if you develop a rash, blistering or peeling of the skin.
• Use a reliable additional method of contraception, as this medicine can stop hormonal contraceptives working properly.
• Report any new anxiety, low mood or unusual thoughts to your prescriber.

Evidence & guidelines

Following a European review, the MHRA restricted modafinil's licensed indication to narcolepsy because of cardiovascular, psychiatric and dermatological risks.