Levodopa / Benserazide

Trade names

• MADOPARK
• MADOPAR
• PROLOPA

Actions

• Benserazide inhibits DOPA decarboxylase, preventing conversion of levodopa to dopamine in peripheral tissues.
• Levodopa (L-DOPA) is the precursor to the neurotransmitters dopamine, norepinephrine and epinephrine.

Route of Administration

Oral

Bioavailability

Levodopa: 30%

Benserazide: 40-70%

Plasma protein binding

Levodopa: 10-30%

Benserazide: 40-70%

Half-life

Levodopa: 0.75–1.5 hours

Benserazide: <30 minutes

Metabolism

Levodopa: Decarboxylation in peripheral tissues and CNS

Benserazide: Metabolized almost entirely in peripheral tissues

Elimination

Benserazide: Renal 53-64%, biliary 24%

Levodopa: ~30% of the dose is excreted in urine unchanged

Important side-effects

Hypotension

Arrhythmias

Nausea, vomiting

Disorientation, confusion, delirium, hallucinations, delusions, psychosis

Dyskinesias

Excessive libido

Vivid dreams or insomnia

Somnolence

Recommended dose

A usual starting dose for patients in the early stages of Parkinson’s disease is 50-100 mg Levodopa 1-2 times per day.

Renal impairment

Benserazide should not be administered to patients with severe renal failure.

Hepatic impairment

Benserazide should not be administered to patients with decompensated hepatic failure.