PEBC: What You Need to Know: Levodopa

Levodopa is converted to dopamine in the brain to treat Parkinson's Disease.

Commonly combined with decarboxylation inhibitors such as benserazide (Prolopa) and carbidopa (Sinemet) to increase penetration into the blood-brain barrier

Dosing:

-multiple times daily (due to short half-life)

-best absorption is empty stomach, but may be taken with food if nausea occurs

-high protein meals may reduce absorption

-domperidone may be added to manage nausea or hypotension

-controlled-release versions can be given at bedtime

Adverse Effects:

-dizziness (hypotension)

-nausea

-hallucinations

-dyskinesia/wearing off, depending on high/low dose

-increased libido

-nightmares/insomnia

-psychosis

-neuroleptic malignant syndrome

-impulse behaviours

Drug Interactions:

-iron and protein reduce levodopa absorption

-antipsychotics may reduce levodopa action through dopamine blockade

-increased dizziness with antihypertensive medications

-isoniazid may reduce levodopa effect

-increased risk of hypertensive crisis with non-selective MAO inhibitors such as tranylcypromine and phenelzine