Drug interactions
Cyproheptadine + Thioridazine
Severity: Moderate
Cyproheptadine and Thioridazine: 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
Both drugs cause sedation and anticholinergic effects, so together they may increase drowsiness, confusion and anticholinergic toxicity. Thioridazine also strongly prolongs the QT interval, and added adverse effects complicate the clinical picture.
What this interaction means in plain words
Cyproheptadine and Thioridazine 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.
Cyproheptadine belongs to Respiratory; Thioridazine belongs to Central Nervous System.
Why it happens
Additive CNS depression and anticholinergic effects from H1, muscarinic and dopamine receptor blockade.
What to do
Monitor for oversedation and anticholinergic effects, and follow ECG and electrolyte monitoring for thioridazine. Use lower doses in older adults.
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 Cyproheptadine
- Cyproheptadine + Isocarboxazid Contraindicated
- Cyproheptadine + Phenelzine Contraindicated
- Cyproheptadine + Tranylcypromine Contraindicated
- Alfentanil + Cyproheptadine Major
- Belladonna and opium + Cyproheptadine Major
- Benzhydrocodone / acetaminophen + Cyproheptadine Major
Other interactions of Thioridazine
- Abiraterone + Thioridazine Contraindicated
- Adagrasib + Thioridazine Contraindicated
- Amiodarone + Thioridazine Contraindicated
- Amisulpride + Thioridazine Contraindicated
- Amitriptyline + Thioridazine Contraindicated
- Amoxapine + Thioridazine Contraindicated
Frequently asked questions
Can I take Cyproheptadine with Thioridazine?
MediHelp rates the interaction as moderate. Cyproheptadine and Thioridazine 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. Both drugs cause sedation and anticholinergic effects, so together they may increase drowsiness, confusion and anticholinergic toxicity. Thioridazine also strongly prolongs the QT interval, and added adverse effects complicate the clinical picture.
How serious is the interaction between Cyproheptadine and Thioridazine?
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 for oversedation and anticholinergic effects, and follow ECG and electrolyte monitoring for thioridazine. Use lower doses in older adults.
What other medicines interact with Cyproheptadine?
MediHelp also lists interactions of Cyproheptadine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Cyproheptadine page.
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