Drug interactions
Prazosin + Timolol
Severity: Moderate
Prazosin and Timolol: 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 lower blood pressure, and beta-blockers can increase the first-dose hypotensive effect of alpha-blockers like prazosin. Postural dizziness and syncope may occur at initiation.
What this interaction means in plain words
Prazosin and Timolol 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.
Prazosin belongs to Genitourinary; Timolol belongs to Cardiovascular.
Why it happens
Additive hypotension from alpha-1 blockade and beta-blockade, with loss of compensatory tachycardia.
What to do
Start prazosin at a low dose at bedtime and advise slow position changes. Monitor standing and sitting blood pressure during titration.
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 Timolol
- Acebutolol + Timolol Major
- Albuterol + Timolol Major
- Aldesleukin + Timolol Major
- Amifostine + Timolol Major
- Amiodarone + Timolol Major
- Arformoterol + Timolol Major
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 Prazosin with Timolol?
MediHelp rates the interaction as moderate. Prazosin and Timolol 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 lower blood pressure, and beta-blockers can increase the first-dose hypotensive effect of alpha-blockers like prazosin. Postural dizziness and syncope may occur at initiation.
How serious is the interaction between Prazosin and Timolol?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start prazosin at a low dose at bedtime and advise slow position changes. Monitor standing and sitting blood pressure during titration.
What other medicines interact with Timolol?
MediHelp also lists interactions of Timolol with, for example, Acebutolol, Albuterol, Aldesleukin. The full list is on the Timolol page.
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