Drug interactions
Imipramine + Levothyroxine
Severity: Moderate
Imipramine and Levothyroxine: moderate 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
Thyroid hormone can increase the sensitivity of adrenergic receptors and may enhance the effects of tricyclic antidepressants, as well as their cardiac toxicity. Patients may develop tachycardia, arrhythmias or CNS stimulation, particularly when thyroid dosing is excessive.
What this interaction means in plain words
Imipramine and Levothyroxine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Imipramine belongs to Central Nervous System; Levothyroxine belongs to Endocrine.
Why it happens
Increased adrenergic receptor sensitivity and enhanced tricyclic pharmacodynamic response.
What to do
Monitor heart rate, ECG and mental status when starting or adjusting levothyroxine in patients taking imipramine. Keep thyroid replacement dosing guided by TSH to avoid hyperthyroid states.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Imipramine
- Dronedarone + Imipramine Contraindicated
- Imipramine + Isocarboxazid Contraindicated
- Imipramine + Phenelzine Contraindicated
- Imipramine + Pimozide Contraindicated
- Imipramine + Rasagiline Contraindicated
- Imipramine + Safinamide Contraindicated
Other interactions of Levothyroxine
Frequently asked questions
Can I take Imipramine with Levothyroxine?
MediHelp rates the interaction as moderate. Imipramine and Levothyroxine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Thyroid hormone can increase the sensitivity of adrenergic receptors and may enhance the effects of tricyclic antidepressants, as well as their cardiac toxicity. Patients may develop tachycardia, arrhythmias or CNS stimulation, particularly when thyroid dosing is excessive.
How serious is the interaction between Imipramine and Levothyroxine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor heart rate, ECG and mental status when starting or adjusting levothyroxine in patients taking imipramine. Keep thyroid replacement dosing guided by TSH to avoid hyperthyroid states.
What other medicines interact with Imipramine?
MediHelp also lists interactions of Imipramine with, for example, Dronedarone, Isocarboxazid, Phenelzine. The full list is on the Imipramine page.
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