Brand Names: Sinemet, Sinemet CR
10/100: 10 mg carbidopa and 100 mg levodopa.
25/100: 25 mg carbidopa and 100 mg levodopa.
25/250: 25 mg carbidopa and 250 mg levodopa.
25/100 CR: 25 mg carbidopa and 100 levodopa.
50/200 CR: 50 mg carbidopa and 200 levodopa.
For the treatment of the symptoms of idiopathic Parkinson’s disease (paralysis agitans), postencephalitic parkinsonism, and symptomatic parkinsonism which may follow injury to the nervous symptom by carbon monoxide or manganese intoxication: Initial dose: One 25/100 tablet three times a day or one CR tablet twice a day. Maintenance dose: Therapy should be individualized and adjusted according to the desired therapeutic response. When a greater proportion of carbidopa is required, one 25/100 tablet may be substituted for two 10/100 tablets. When a greater portion of levodopa is required, a 25/250 tablet should be substituted at a dosage of one tablet three or four times a day, up to eight tablets per day. Tablets of the two ratios may be given separately or combined to provide the optimum dosage. CR tablets may be taken whole or in half tablets but should not be crushed or chewed.
Pharmacology/Pharmacokinetics:
Levodopa crosses the blood-brain barrier and is converted into dopamine in the basal ganglia. A large portion of levodopa is converted to dopamine in extracerebral tissue. Dopamine does not cross the blood-brain barrier. Carbidopa inhibits dopa-decarboxylase in extracerebral tissue, thereby increasing the level of levodopa available to the central nervous system, and decreases the side effects (nausea) seen from high levels of peripheral dopamine.
Drug Interactions:
Hydantoins and pyridoxine (vitamin B6) may decrease effectiveness. Hypertensive crisis may occur if given with MONOAMINE OXIDASE INHIBITORS.
Contraindication/Precautions:
Use is contraindicated in patients with narrow-angle glaucoma, in patients with a suspicious, undiagnosed skin lesion or a history of melanomas, and in patients currently taking monoamine oxidase inhibitors or within 14 days of therapy. Use with caution in patients with present or past psychosis, severe cardiovascular or pulmonary disease, peptic ulcer, bronchial asthma, and renal, hepatic, or endocrine disease. Also use in caution in pregnancy and lactation. Discontinue current levodopa therapy at least 8 hours before initiation of therapy. Pregnancy Category C.
Adverse Effects:
DYSTONIC or involuntary movements, depression, dementia, and nausea.
May be taken with food or milk if GI upset occurs.
Avoid vitamin products containing vitamin B6 (pyridoxine).
Extended-release tablets may be given whole or in half tablets but should not be crushed or chewed.
Store in a cool, dry place away from sunlight and children.
If a dose is missed take it as soon as possible. If it is closer to the time of your next dose than the dose you missed, skip the missed dose and return to your dosing schedule. Do not double doses.
Contact a physician if the above side effects are severe or persistent.
