Isocarboxazid

How it works

It irreversibly inhibits monoamine oxidase, reducing the breakdown of noradrenaline, serotonin and dopamine and thereby increasing their availability in the brain.

Prescribing in practice

• Concurrent intake of tyramine-rich foods or interacting sympathomimetic or serotonergic medicines can precipitate a hypertensive crisis or serotonin syndrome, so strict dietary and drug restrictions are essential.
• Adequate washout periods are required when switching to or from other antidepressants to avoid dangerous interactions.
• Avoid combination with other serotonergic agents, including SSRIs, certain opioids and triptans.

Monitoring

Monitor blood pressure and watch for signs of hypertensive crisis and serotonin syndrome, alongside mood and suicidal ideation.

Counselling the patient

• Provide the dietary restriction card and explain which foods and drinks to avoid.
• Do not take other medicines, including over-the-counter remedies, without checking for interactions.
• Seek urgent help for severe headache, palpitations or neck stiffness.

Evidence & guidelines

Isocarboxazid is an established MAOI reserved for depression unresponsive to other treatments, with well-recognised dietary and drug interactions documented in current prescribing references.