Drug interactions
Carbidopa + Isoniazid
Severity: Moderate
Carbidopa and Isoniazid: 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
Isoniazid may reduce the benefit of levodopa/carbidopa in some patients, causing worsening of parkinsonian symptoms, and may add hypertensive risk.
What this interaction means in plain words
Carbidopa and Isoniazid 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 belongs to Central Nervous System; Isoniazid belongs to Anti Bacterial.
Why it happens
Isoniazid has weak MAO inhibition and pyridoxine-related effects; the mechanism is not fully established.
What to do
Monitor motor response and blood pressure when isoniazid is started, and adjust levodopa dose as needed.
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 Carbidopa
Other interactions of Isoniazid
Frequently asked questions
Can I take Carbidopa with Isoniazid?
MediHelp rates the interaction as moderate. Carbidopa and Isoniazid 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. Isoniazid may reduce the benefit of levodopa/carbidopa in some patients, causing worsening of parkinsonian symptoms, and may add hypertensive risk.
How serious is the interaction between Carbidopa and Isoniazid?
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 motor response and blood pressure when isoniazid is started, and adjust levodopa dose as needed.
What other medicines interact with Carbidopa?
MediHelp also lists interactions of Carbidopa with, for example, Metoclopramide, Amlodipine-atorvastatin, Amlodipine-benazepril. The full list is on the Carbidopa page.
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