Carbidopa and Levodopa

Carbidopa and levodopa extended-release tablets are indicated in the treatment of Parkinson’s disease, post-encephalitic parkinsonism, and symptomatic parkinsonism that may follow carbon monoxide intoxication or manganese intoxication.

Nonselective monoamine oxidase (MAO) inhibitors are contraindicated for use with carbidopa and levodopa extended-release tablets. These inhibitors must be discontinued at least two weeks prior to initiating therapy with carbidopa and levodopa extended-release. Carbidopa and levodopa extended-release may be administered concomitantly with the manufacturer’s recommended dose of an MAO inhibitor with selectivity for MAO type B (e.g., selegiline HCl) (see PRECAUTIONS: Drug Interactions ).

Carbidopa and levodopa extended-release is contraindicated in patients with known hypersensitivity to any component of this drug and in patients with narrow-angle glaucoma.

When patients are receiving levodopa without a decarboxylase inhibitor, levodopa must be discontinued at least twelve hours before carbidopa and levodopa extended-release is started. In order to reduce adverse reactions, it is necessary to individualize therapy. See DOSAGE AND ADMINISTRATION section before initiating therapy. Carbidopa and levodopa extended-release should be substituted at a dosage that will provide approximately 25% of the previous levodopa dosage (see DOSAGE AND ADMINISTRATION ).

Carbidopa does not decrease adverse reactions due to central effects of levodopa. By permitting more levodopa to reach the brain, particularly when nausea and vomiting is not a dose-limiting factor, certain adverse central nervous system (CNS) effects, e.g., dyskinesias, will occur at lower dosages and sooner during therapy with carbidopa and levodopa extended-release than with levodopa alone. Patients receiving carbidopa and levodopa extended-release may develop increased dyskinesias compared to carbidopa and levodopa immediate-release.

Dyskinesias are a common side effect of carbidopa-levodopa treatment. The occurrence of dyskinesias may require dosage reduction. All patients should be observed carefully for the development of depression with concomitant suicidal tendencies. Carbidopa and levodopa extended-release should be administered cautiously to patients with severe cardiovascular or pulmonary disease, bronchial asthma, renal, hepatic or endocrine disease.