Drug interactions
Ketotifen + Protriptyline
Severity: Moderate
Ketotifen and Protriptyline: 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
Protriptyline is a tricyclic antidepressant with anticholinergic effects, and ketotifen is a sedating antihistamine with some anticholinergic activity. Together they may increase drowsiness and anticholinergic effects such as dry mouth, constipation and urinary retention. Protriptyline is less sedating than other tricyclics, so the effect may be modest.
What this interaction means in plain words
Ketotifen and Protriptyline 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.
Why it happens
Additive central nervous system depression and anticholinergic effects through H1 and muscarinic receptor blockade.
What to do
Monitor for sedation and anticholinergic effects, particularly in older patients. Reduce doses or choose a non-sedating antihistamine if these effects occur.
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 Ketotifen
- Ketotifen + Phenobarbital Moderate
- Ketotifen + Pholcodine Moderate
- Ketotifen + Primidone Moderate
- Ketotifen + Quazepam Moderate
- Ketotifen + Rotigotine Moderate
- Ketotifen + Sufentanil Moderate
Frequently asked questions
Can I take Ketotifen with Protriptyline?
MediHelp rates the interaction as moderate. Ketotifen and Protriptyline 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. Protriptyline is a tricyclic antidepressant with anticholinergic effects, and ketotifen is a sedating antihistamine with some anticholinergic activity. Together they may increase drowsiness and anticholinergic effects such as dry mouth, constipation and urinary retention. Protriptyline is less sedating than other tricyclics, so the effect may be modest.
How serious is the interaction between Ketotifen and Protriptyline?
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 sedation and anticholinergic effects, particularly in older patients. Reduce doses or choose a non-sedating antihistamine if these effects occur.
What other medicines interact with Ketotifen?
MediHelp also lists interactions of Ketotifen with, for example, Phenobarbital, Pholcodine, Primidone. The full list is on the Ketotifen page.
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