Selegiline

How it works

It selectively and irreversibly inhibits MAO-B, reducing dopamine breakdown in the brain and enhancing dopaminergic transmission; some of its metabolites are amfetamine derivatives.

Prescribing in practice

• It must not be combined with pethidine, and concurrent serotonergic agents or other MAO inhibitors risk serotonin syndrome or hypertensive crisis, so combinations require careful review.
• Amfetamine metabolites may cause insomnia or agitation, so dosing earlier in the day is generally preferred.
• When added to levodopa it can intensify dopaminergic adverse effects, sometimes necessitating a reduction in the levodopa dose.

Monitoring

Monitor for dopaminergic effects, dyskinesia, impulse-control disorders, sleep disturbance and any features suggestive of serotonin toxicity when serotonergic drugs are co-prescribed.

Counselling the patient

• Report new compulsive behaviours such as gambling, hypersexuality or excessive spending.
• Take the medicine earlier in the day to reduce the chance of insomnia.
• Tell any prescriber you take selegiline before starting new medicines, especially antidepressants and certain painkillers.

Evidence & guidelines

Selegiline is a long-established treatment option in Parkinson's disease and features among the MAO-B inhibitors recommended in NICE guidance.