Each 10/100 tablet contains: carbi-dopa, 10 mg, and levodopa, 100 mg. Each 25/100 tablets contains: carbido-pa, 25 mg, and levodopa, 100 mg. Each 25/250 tablet contains: carbi-dopa, 25 mg, and levodopa, 250 mg. Each sustained-release tablet contains: carbidopa, 50 mg, and levodo-pa, 200 mg.
Action/Kinetics: Carbidopa inhibits peripheral decarboxylation
(breakdown) of levodopa. Since peripheral decarboxylation is inhibited, this allows more levodopa to be available for transport to the brain,
■ where it will be converted to dopa-mine, thus relieving the symptoms of parkinsonism. It is recommended that both carbidopa and levodopa be given together (e.g., Sinemet). However, the dosage of levodopa must be reduced by up to 80% when combined with carbidopa. This decreases the incidence of levodopa-induced side effects. NOTE: Pyridox-ine will not reverse the action of car-bidopa/levodopa. tv2, carbidopa: 1-2 hr; when given with levodopa, the t1/2 of levodopa increases from 1 hr to 2 hr (may be as high as 15 hr in some clients). About 30% carbidopa is excreted unchanged in the urine. Uses: All types of parkinsonism (id-iopathic, postencephalitic, following injury to the nervous system due to carbon monoxide and manganese intoxication). Carbidopa alone is used in clients who require individual titration of carbidopa and levodo-pa. Non-FDA Approved Uses: Post-anoxic intention myoclonus. Warning: Levodopa must be discontinued at least 8 hr before carbidopa/levodo-pa therapy is initiated. Also, clients taking carbidopa/levodopa must not take levodopa concomitantly, because the former is a combination of carbidopa and levodopa. Contraindications: History of melanoma. MAO inhibitors should be stopped 2 weeks before therapy. Lactation.
Special Concerns: Use during pregnancy only if benefits outweigh risks. Safety and efficacy in children less than 18 years of age have not been determined. Lower doses may be necessary in geriatric clients due to aged-related decreases in peripheral dopa decarboxylase. Side Effects: Because more levodo-pa reaches the brain, dyskinesias may occur at lower doses with carbi-dopa/levodopa than with levodopa alone. Clients abruptly withdrawn from levodopa may experience neu-roleptic malignant-like syndrome in cluding symptoms of muscular rigidity, hyperthermia, increased serum phosphokinase, and changes in mental status.
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