- What is levodopa-carbidopa, and how does it work (mechanism of action)?
- What brand names are available for levodopa-carbidopa?
- Is levodopa-carbidopa available as a generic drug?
- Do I need a prescription for levodopa-carbidopa?
- What are the uses for levodopa-carbidopa?
- What are the side effects of levodopa-carbidopa?
- What is the dosage for levodopa-carbidopa?
- Which drugs or supplements interact with levodopa-carbidopa?
- Is levodopa-carbidopa safe to take if I'm pregnant or breastfeeding?
- What else should I know about levodopa-carbidopa?
What is the dosage for levodopa-carbidopa?
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.
Which drugs or supplements interact with levodopa-carbidopa?
The use of the following drugs with carbidopa-levodopa can enhance the anti-Parkinson's effects of levodopa:
- amantadine (Symmetrel),
- benztropine (Cogentin),
- procyclidine (Kemadrin), or
- trihexyphenidyl (Artane)
The following drugs can inhibit dopamine in the brain and shouldn't be used in combination with levodopa:
- haloperidol (Haldol),
- loxapine (Loxitane),
- metoclopramide (Reglan),
- phenothiazines such as prochlorperazine (Thorazine); and
- thioxanthenes as thiothixene (Navane).
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.
The occurrence of postural hypotension (reduced blood pressure when standing from a sitting or lying down position) may increase when carbidopa-levodopa is combined with drugs that reduce blood pressure. Phenytoin (Dilantin) can increase the break-down of carbidopa-levodopa, reducing its effectiveness. Use of carbidopa-levodopa with monoamine oxidase inhibitors (MAOI's) antidepressants, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane), can result in severe and dangerous elevations in blood pressure. MAOI's should be stopped 2-4 weeks before starting carbidopa-levodopa therapy.
Quick GuideParkinson's Disease: Symptoms, Causes, Stages, Treatment
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