Drug interactions
Isoniazid + Venlafaxine
Severity: Minor
Isoniazid and Venlafaxine: 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 venlafaxine inhibits serotonin and norepinephrine reuptake. Combined use carries a theoretical risk of serotonin toxicity or blood pressure elevation, though reports are scarce.
What this interaction means in plain words
Isoniazid and Venlafaxine 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 belongs to Anti Bacterial; Venlafaxine belongs to Central Nervous System.
Why it happens
Weak MAO inhibition by isoniazid may add to serotonin and norepinephrine reuptake inhibition by venlafaxine.
What to do
Monitor for agitation, tremor, sweating, hyperthermia and hypertension after starting or adjusting either drug. Discontinue one agent if serotonin toxicity occurs.
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
Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Isoniazid with Venlafaxine?
MediHelp rates the interaction as minor. Isoniazid and Venlafaxine 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 venlafaxine inhibits serotonin and norepinephrine reuptake. Combined use carries a theoretical risk of serotonin toxicity or blood pressure elevation, though reports are scarce.
How serious is the interaction between Isoniazid and Venlafaxine?
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, sweating, hyperthermia and hypertension after starting or adjusting either drug. Discontinue one agent if serotonin toxicity occurs.
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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