What will happen if pyridoxine is given with levodopa?

Pyridoxine (vitamin B6) can reduce the effectiveness of levodopa. Pyridoxine increases the metabolism of levodopa in the liver and peripheral tissues, resulting in decreased bioavailability of levodopa to the brain. This can compromise the therapeutic efficacy of levodopa and necessitate higher doses to achieve the desired clinical effect.

When pyridoxine is coadministered with levodopa, patients may experience a reduction in the therapeutic effects of levodopa, including decreased symptom control, increased motor fluctuations, and diminished "on" time. The extent of this interaction varies among individuals and depends on several factors such as the dose of pyridoxine, the levodopa formulation being used, and the individual's sensitivity to pyridoxine.

To avoid this interaction, it is generally recommended that patients taking levodopa avoid taking high doses of pyridoxine supplements. The daily dose of pyridoxine should not exceed the Recommended Dietary Allowance (RDA) of 1.7 mg for adults (19 years and older). Individuals who are prescribed levodopa and are concerned about their dietary intake of pyridoxine should consult their doctor or pharmacist for guidance.

In some cases, when pyridoxine deficiency is suspected or confirmed, a doctor may recommend a low dose of pyridoxine to be taken along with levodopa to prevent or correct deficiency. However, this should be done under medical supervision to ensure that the dose of pyridoxine does not interfere with the effectiveness of levodopa therapy.