Drug interactions
Olanzapine / samidorphan + Prazosin
Severity: Moderate
Olanzapine / samidorphan and Prazosin: 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
Olanzapine has alpha-1 blocking activity and can cause orthostatic hypotension, which may add to the effect of prazosin. Patients may experience dizziness, falls or syncope, especially at initiation or with dose increases.
What this interaction means in plain words
Olanzapine / samidorphan and Prazosin 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 alpha-1 adrenergic antagonism causing vasodilation and orthostatic hypotension.
What to do
Monitor blood pressure and orthostatic symptoms when starting or increasing olanzapine/samidorphan. Reduce the prazosin dose if hypotension develops.
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 Prazosin
- Alfuzosin + Prazosin Major
- Amifostine + Prazosin Major
- Avanafil + Prazosin Major
- Doxazosin + Prazosin Major
- Dutasteride-tamsulosin + Prazosin Major
- Phenoxybenzamine + Prazosin Major
Frequently asked questions
Can I take Olanzapine / samidorphan with Prazosin?
MediHelp rates the interaction as moderate. Olanzapine / samidorphan and Prazosin 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. Olanzapine has alpha-1 blocking activity and can cause orthostatic hypotension, which may add to the effect of prazosin. Patients may experience dizziness, falls or syncope, especially at initiation or with dose increases.
How serious is the interaction between Olanzapine / samidorphan and Prazosin?
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 blood pressure and orthostatic symptoms when starting or increasing olanzapine/samidorphan. Reduce the prazosin dose if hypotension develops.
What other medicines interact with Prazosin?
MediHelp also lists interactions of Prazosin with, for example, Alfuzosin, Amifostine, Avanafil. The full list is on the Prazosin page.
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