Drug interactions
Olanzapine / samidorphan + Phentolamine
Severity: Moderate
Olanzapine / samidorphan and Phentolamine: 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 effects of phentolamine. This may lead to dizziness, syncope or falls.
What this interaction means in plain words
Olanzapine / samidorphan and Phentolamine 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 blockade and hypotensive effects.
What to do
Monitor blood pressure, including orthostatic measurements, and reduce the antihypertensive dose if needed. Counsel patients to rise slowly.
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 Phentolamine
Frequently asked questions
Can I take Olanzapine / samidorphan with Phentolamine?
MediHelp rates the interaction as moderate. Olanzapine / samidorphan and Phentolamine 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 effects of phentolamine. This may lead to dizziness, syncope or falls.
How serious is the interaction between Olanzapine / samidorphan and Phentolamine?
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, including orthostatic measurements, and reduce the antihypertensive dose if needed. Counsel patients to rise slowly.
What other medicines interact with Phentolamine?
MediHelp also lists interactions of Phentolamine with, for example, Alfuzosin, Avanafil, Doxazosin. The full list is on the Phentolamine page.
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