Therapeutic Agents in Parkinsonism

An overview of the drugs used to treat Parkinson disease is shown in Table 10-1. The primary drug used is levodopa. Other agents such as amantadine, anticholinergic drugs, catechol-O-methyltransferase 

Drug Levodopa Mechanism of Action Resolves dopamine deficiency by being converted to dopamine after crossing blood-brain barrier. Special Comments Still the best drug for resolving parkinsonian symptoms long-term use limited by side effects and decreased efficacy. 

Dopamine agonists Bromocriptine Cabergoline Pergolide Pramipexole Ropinirole Directly stimulates dopamine receptors in basal ganglia. May produce fewer side effects (dyskinesias, fluctuations in response) than levodopa preliminary evidence suggests that early use may also delay the progression of Parkinson disease. 

Anticholinergics (see Table 10-2) Inhibit excessive acetylcholine influence caused by dopamine deficiency. Use in Parkinson disease limited by frequent side effects. 

Amantadine Unclear may inhibit the effects of excitatory amino acids in the basal ganglia. May be used alone during early/mild stages or added to drug regimen when levodopa loses effectiveness. 

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Bonifati V, Meco G. New, selective catechol-O-methyltransferase inhibitors as therapeutic agents in Parkinson s disease. Pharmacol. Ther. 1999 8 1-36. 

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