Carbidopa Dosage

This dosage information may not include all the information needed to use Carbidopa safely and effectively. See additional information for Carbidopa.

The information at is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Parkinsonian Tremor

25 mg three to four times a day. Give at the same time with levodopa, at 2% to 25% of the previous or recommended daily dosage of levodopa when taken alone.

In patients already on levodopa, allow 12 hours between the last dose of levodopa and the initiation of therapy with carbidopa and levodopa.

Maximum daily dosage should not exceed 200 mg.

Usual Adult Dose for Neuroleptic Malignant Syndrome

Case Report:
Carbidopa 25 mg/levodopa 250 mg three times daily via nasogastric tube for 2 days.

Usual Pediatric Dose for GTP-CH Deficiency

Case Reports:
>1 year:
Initial: 5 mg/kg/day of carbidopa/levodopa, then titrated slowly downward with the aim of maintaining control of extrapyramidal syndrome.

Dose Adjustments

Most patients respond to a 1:10 proportion of carbidopa and levodopa, provided the daily dosage of carbidopa is 70 mg or more a day.

In patients already receiving carbidopa-levodopa (<70 mg carbidopa/day, <700 mg levodopa/day), who require additional carbidopa, give 25 mg of carbidopa with the first dose of carbidopa-levodopa each day. Additional doses of 12.5 mg or 25 mg may be given during the day with each dose of carbidopa-levodopa.


Periodic evaluations of hepatic, hematopoietic, cardiovascular, and renal function are recommended during therapy with carbidopa.

Liver function tests changes may include elevations of alkaline phosphatase, SGOT (AST), SGPT (ALT), lactic dehydrogenase, and bilirubin. Abnormalities in blood urea nitrogen and positive Coombs test have been reported.

Patients diagnosed with chronic wide-angle glaucoma should be closely monitored for changes in intraocular pressure during therapy.

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