Drug interactions
Carbidopa-levodopa + Phentolamine
Severity: Moderate
Carbidopa-levodopa 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
Levodopa can lower blood pressure and cause orthostatic hypotension, and phentolamine is a potent alpha-blocking vasodilator. Taken together they can produce additive hypotension, dizziness and falls, particularly when treatment is started or doses are raised.
What this interaction means in plain words
Carbidopa-levodopa 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.
Carbidopa-levodopa belongs to Central Nervous System; Phentolamine belongs to Cardiovascular.
Why it happens
Additive pharmacodynamic hypotensive effects from dopamine-mediated vasodilation and sympathetic inhibition with alpha-adrenergic blockade.
What to do
Check blood pressure, including standing readings, when either drug is started or changed. Reduce the dose of the antihypertensive agent if symptomatic hypotension occurs.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Carbidopa-levodopa and Phentolamine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Carbidopa-levodopa
- Carbidopa-levodopa + Isocarboxazid Contraindicated
- Carbidopa-levodopa + Phenelzine Contraindicated
- Carbidopa-levodopa + Selegiline transdermal Contraindicated
- Carbidopa-levodopa + Tranylcypromine Contraindicated
- Amisulpride + Carbidopa-levodopa Major
- Asenapine + Carbidopa-levodopa Major
Other interactions of Phentolamine
Frequently asked questions
Can I take Carbidopa-levodopa with Phentolamine?
MediHelp rates the interaction as moderate. Carbidopa-levodopa 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. Levodopa can lower blood pressure and cause orthostatic hypotension, and phentolamine is a potent alpha-blocking vasodilator. Taken together they can produce additive hypotension, dizziness and falls, particularly when treatment is started or doses are raised.
How serious is the interaction between Carbidopa-levodopa 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: Check blood pressure, including standing readings, when either drug is started or changed. Reduce the dose of the antihypertensive agent if symptomatic hypotension occurs.
What other medicines interact with Carbidopa-levodopa?
MediHelp also lists interactions of Carbidopa-levodopa with, for example, Isocarboxazid, Phenelzine, Selegiline transdermal. The full list is on the Carbidopa-levodopa page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
