levodopa-carbidopa, Sinemet, Sinemet CR, Parcopa (cont.)

Gastrointestinal side effects are common in patients receiving carbidopa-levodopa. Nausea, vomiting, loss of appetite, and weight loss may occur. Patients may experience dizziness upon standing up, associated with a drop in blood pressure. Fortunately, the body develops tolerance to this side effect within a few months. Infrequently, patients may develop a drop in white blood cell count during carbidopa-levodopa therapy. This is a reason to temporarily, if not permanently, stop treatment.



PREPARATIONS: Tablets (carbidopa/levodopa): 10/100, 25/100 mg. Tablets (Controlled Release): 25/100 and 50/200 mg.

STORAGE: Tablets should be kept at room temperature, 15-30 C (59-86 F).

DOSING: Carbidopa-levodopa is taken several times per day. It may be administered with food to reduce the likelihood of nausea; however, a high-protein diet may reduce its absorption. The initial dose using regular tablets is 25/100 mg three times daily. The dose may be increased by one tablet every day or every other day until 8 tablets of 25/100 mg daily is reached. Alternatively 10/100 mg three or four times daily may be used initially and increased by one tablet daily or every other day until a total of eight tablets daily is reached. The dose of controlled release tablets is 50/200 mg twice daily and may increase up to 1.6 grams levodopa daily. Controlled release tablet should be given at least 6 hours apart.

DRUG INTERACTIONS: The use of amantadine (Symmetrel), benztropine (Cogentin), procyclidine (Kemadrin), or trihexyphenidyl (Artane) with carbidopa-levodopa can enhance the anti- Parkinson's effects of levodopa. Droperidol, haloperidol (Haldol), loxapine (Loxitane), metoclopramide (Reglan), phenothiazines such as prochlorperazine (Thorazine); thioxanthenes as thiothixene (Navane) inhibit dopamine in the brain. These drugs, therefore, can worsen Parkinson's disease and reverse the beneficial effects of levodopa. Methyldopa (Aldomet) and reserpine also can interfere with the beneficial actions of carbidopa-levodopa and can increase the risk of side effects.

Medically Reviewed by a Doctor on 12/30/2014

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