Nialamide (Niamid, Niamide, Nuredal, Surgex) is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class that was used as an antidepressant.

[2] It was withdrawn by Pfizer several decades ago due to the risk of hepatotoxicity.

[3][4] Side effects include agitation and insomnia, less frequently dry mouth, dizziness, blurred vision, and hypomania, and rarely leukopenia and hepatitis.

As with other MAOIs, a hypertensive crisis can be triggered by co-ingestion of tyramine.

It is metabolized into isoniazid, an anti-tuberculosis agent, and so is contraindicated in patients with tuberculosis.