No

Anti-Parkinson's Agent (Dopamine Agonist)

Given with levodopa in the treatment of parkinsonism to enable a lower dosage of levodopa to be used and a more rapid response to be obtained and to decrease side-effects; for details of administration and dosage, see Levodopa; has no effect without levodopa

C

Hypersensitivity to carbidopa or levodopa

Adverse reactions are associated with concomitant administration with levodopa

1% to 10%:

Cardiovascular: Orthostatic hypotension, palpitations, cardiac arrhythmias

Central nervous system: Memory loss, nervousness, insomnia, fatigue, hallucinations, ataxia, dystonic movements

Gastrointestinal: Nausea, vomiting, GI bleeding

Ocular: Blurred vision

<1%: Hypertension, duodenal ulcer, hemolytic anemia

Increased toxicity: Tricyclic antidepressant hypertensive reactions and dyskinesia

Carbidopa is a peripheral decarboxylase inhibitor with little or no pharmacological activity when given alone in usual doses. It inhibits the peripheral decarboxylation of levodopa to dopamine; and as it does not cross the blood-brain barrier, unlike levodopa, effective brain concentrations of dopamine are produced with lower doses of levodopa. At the same time, reduced peripheral formation of dopamine reduces peripheral side-effects, notably nausea and vomiting, and cardiac arrhythmias, although the dyskinesias and adverse mental effects associated with levodopa therapy tend to develop earlier.

Absorption: Rapid but incomplete from GI tract

Distribution: Does not cross the blood-brain barrier; in rats, it has been reported to cross the placenta and to be excreted in milk

Elimination: Rapidly excreted in urine both unchanged and in the form of metabolites

Adults: Oral: 70-100 mg/day; maximum daily dose: 200 mg

May be administered with meals to decrease GI upset

No information available to require special precautions

Dopaminergic therapy in Parkinson's disease includes the use of carbidopa in combination with levodopa. Carbidopa/levodopa combination is associated with orthostatic hypotension. Patients medicated with this drug combination should be carefully assisted from the chair and observed for signs of orthostatic hypotension.

Can take with food to prevent GI upset, do not stop taking this drug even if you do not think it is working; dizziness, lightheadedness, fainting may occur when getting up from a sitting or lying position

Tablet: 25 mg