Levodopa/Carbidopa Oral: Dosing and Precautions

Therapeutic action

Antiparkinson drug.

Indications

Parkinson's disease and extrapyramidal disorders except those induced by antipsychotics.

Forms and strengths

• 100 mg levodopa + 10 mg carbidopa tablet.
• 250 mg levodopa + 25 mg carbidopa tablet.

Dose

Doses are expressed as levodopa.

• Adult: initial dose 50 to 125 mg 3 times daily, immediately after meals.
• Increase by 50 to 125 mg every day or every 2 days until the optimal dose for the individual patient is reached.
• Maintenance dose usually: 250 to 500 mg 3 times daily, immediately after meals, maximum 2 g daily.
• Reduce dosage in older patients.

Duration

According to clinical response.

Contra-indications, adverse effects, precautions

• Do not administer in severe psychosis, confusion, closed-angle glaucoma, recent myocardial infarction, or malignant melanoma.
• Early in treatment when dose is not adjusted, may cause anorexia, vomiting, orthostatic hypotension, cardiac arrhythmia, agitation, insomnia or drowsiness, and depression.
• Frequent delayed adverse effects or signs of excessive dosage include dyskinesia and tremor.
• Mental disorders are more frequent in older patients and may include confusional state or depression with or without suicidal tendencies.
• Later in treatment, fluctuation of effect during the day or reduction of effect may occur.
• Administer with caution in mental disorders, cardiac disease, and gastroduodenal ulcer.
• Do not administer simultaneously with MAOI antidepressants, antipsychotics, or reserpine.
• Pregnancy: contraindicated.
• Breast-feeding: contraindicated.