Drug interactions
Isoniazid + Protriptyline
Severity: Minor
Isoniazid and Protriptyline: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Isoniazid has weak MAO-inhibiting activity, and combining it with a tricyclic antidepressant such as protriptyline may theoretically increase serotonergic or adrenergic effects. Clinically significant reactions are rarely reported.
What this interaction means in plain words
Isoniazid and Protriptyline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Weak MAO inhibition by isoniazid may add to the monoamine reuptake inhibition of protriptyline.
What to do
Monitor for agitation, tremor, tachycardia and sweating when starting the combination. Reduce the protriptyline dose if symptoms develop.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Isoniazid
Frequently asked questions
Can I take Isoniazid with Protriptyline?
MediHelp rates the interaction as minor. Isoniazid and Protriptyline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Isoniazid has weak MAO-inhibiting activity, and combining it with a tricyclic antidepressant such as protriptyline may theoretically increase serotonergic or adrenergic effects. Clinically significant reactions are rarely reported.
How serious is the interaction between Isoniazid and Protriptyline?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for agitation, tremor, tachycardia and sweating when starting the combination. Reduce the protriptyline dose if symptoms develop.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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