Drug interactions
Levodopa + Vitamin B6
Severity: Moderate
Levodopa and Vitamin B6: 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
Pyridoxine can reduce the effectiveness of levodopa given alone by speeding its conversion to dopamine outside the brain. Less levodopa reaches the central nervous system, so parkinsonian symptoms may worsen. The effect is largely prevented when levodopa is combined with a decarboxylase inhibitor such as carbidopa or benserazide.
What this interaction means in plain words
Levodopa and Vitamin B6 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 belongs to Central Nervous System; Vitamin B6 belongs to Gastrointestinal Tract.
Why it happens
Pyridoxine is a cofactor for peripheral dopa decarboxylase, increasing peripheral conversion of levodopa to dopamine.
What to do
Avoid pyridoxine supplements in patients taking levodopa without a decarboxylase inhibitor. With carbidopa or benserazide combinations, no routine adjustment is usually 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 Vitamin B6
- Ethotoin + Vitamin B6 Moderate
- Fosphenytoin + Vitamin B6 Moderate
- Isoniazid + Vitamin B6 Moderate
- Penicillamine + Vitamin B6 Moderate
- Phenobarbital + Vitamin B6 Moderate
- Phenytoin + Vitamin B6 Moderate
Other interactions of Levodopa
- Isocarboxazid + Levodopa Contraindicated
- Levodopa + Phenelzine Contraindicated
- Levodopa + Phenelzine (nonselective MAOI) Contraindicated
- Levodopa + Procarbazine Contraindicated
- Levodopa + Tranylcypromine Contraindicated
- Amisulpride + Levodopa Major
Frequently asked questions
Can I take Levodopa with Vitamin B6?
MediHelp rates the interaction as moderate. Levodopa and Vitamin B6 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. Pyridoxine can reduce the effectiveness of levodopa given alone by speeding its conversion to dopamine outside the brain. Less levodopa reaches the central nervous system, so parkinsonian symptoms may worsen. The effect is largely prevented when levodopa is combined with a decarboxylase inhibitor such as carbidopa or benserazide.
How serious is the interaction between Levodopa and Vitamin B6?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid pyridoxine supplements in patients taking levodopa without a decarboxylase inhibitor. With carbidopa or benserazide combinations, no routine adjustment is usually needed.
What other medicines interact with Vitamin B6?
MediHelp also lists interactions of Vitamin B6 with, for example, Ethotoin, Fosphenytoin, Isoniazid. The full list is on the Vitamin B6 page.
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