Carbidopa-levodopa (Sinemet CR) (p172) Antiparkinsonism agent

Action: Decarboxylation of levodopa to periphery is inhibited by carbidopa; more levodopa is made available for transport to brain and conversion to dopamine in the brain

Therapeutic Outcome: Absence of involuntary movements

Uses: Parkinson’s disease, Parkinsonism resulting from carbon monoxide, chronic manganese intoxication, cerebral arteriosclerosis

Adv. Reaction: hemolytic anemia, leucopenia, agranulocytosis, Involuntary choreiform movements, hand tremors, fatigue, headache, anxiety, twitching, numbness, weakness, confusion, agitation, insomnia, nightmares, psychosis, hallucination, orthostatic hypotension, GI upset

Contraindicated: angle-closure glaucoma, malignant melanoma, unDx skin lesions resembling melanoma

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Carbidopa-levodopa (Sinemet CR) (p172) Antiparkinsonism agent

Precautions: breastfeeding, diabetes, renal/cardiac/hepatic/respiratory disease, MI with dysrhythmias, open-angle glaucoma, seizures, peptic ulcer, depression

Interactions: MAOIs (hypertensive crisis); protein (decreased absorption of levodopa);

Implementation: PO route -> give product until NPO before surgery; adjust dosage depending on pt response; give with meals or after meals to prevent GI symptoms; limit protein taken with product; give only after MAOIs have been d/c for 2wks; if on levodopa d/c for at least 8 wks before changing to levodopa-carbidopa

Pt/family teaching: change position slowly to prevent orthostatic hypotension; report side effects (twitching, eye spasm, grimacing, protrusion of tongue, personality changes – may indicate overdose); use product as prescribed; don’t d/c abruptly because a parkinsonian crisis may occur; don’t double doses but take

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Carbidopa-levodopa (Sinemet CR) (p172) Antiparkinsonism agent

missed dose as soon as you remember up to 2hrs before next dose; urine and sweat may darken but is harmless; exercise to maintain mobility and lessen spasm; check with MD before using OTC medicines; drowsiness, dizziness are common; sips of water, hard candy may lessen dry mouth;

Evaluation: Positive outcome (decrease akathisia, improved mood, decreased involuntary movements)

Dosage/Routes: PO 25mg carbidopa/ 100 mg levodopa tid, may increase daily or every other day by 1 tab to desired response (8 tabs/day); EXT REL tabs carbidopa 5 mg/ levodopa 100 mg 1 tab tid-qid, may increase by 1 tab daily or q other day until 8tabs reached

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