| Anticholinergics |
| Benztropine (Cogentin), trihexyphenidyl (Artane) | Dry mouth, dry eyes, constipation, hypotension, cognitive impairment, urinary retention | Useful for symptomatic control of Parkinson’s disease (benefits are mild to moderate); associated with more adverse effects than other drugs |
| Carbidopa/levodopa |
| Immediate- and sustained-release carbidopa/levodopa (Sinemet) | Nausea, somnolence, dyskinesia, hypotension, hallucinations | Levodopa is the most effective medication and remains the primary treatment for symptomatic Parkinson’s disease; no added benefit for motor complications with sustained-release versus immediate-release preparations |
| COMT inhibitors |
| Entacapone (Comtan) | Diarrhea; exacerbates levodopa adverse effects; bright orange urine | Useful for managing motor fluctuations (“wearing-off” effect) in patients taking levodopa; levodopa dose may need to be reduced if dyskinesia appears |
| Tolcapone (Tasmar) | Diarrhea; exacerbates levodopa adverse effects; rare liver failure (liver function monitoring needed) |
| Dopamine agonists |
| Bromocriptine (Parlodel) | Nausea, headache, dizziness | Useful for early and advanced disease |
| Pergolide (Permax) | Somnolence; hallucinations; nausea; edema; fibrosis of cardiac valves, lung, and retroperitoneum; retroperitoneal and pulmonary fibrosis | Useful for the initial treatment of parkinsonism and as adjunct therapy in patients taking levodopa |
| Pramipexole (Mirapex), Ropinirole (Requip) | Nausea, sleep attacks, edema, hallucinations, hypotension | Useful for early disease and in patients with Parkinson’s disease and motor fluctuations |
| MAO-B inhibitors |
| Selegiline (Eldepryl) | Nausea, insomnia, drug interactions with other MAO inhibitors/tyramine | Useful for symptomatic control of Parkinson’s disease (benefits are mild to moderate) and as adjuvant therapy for patients with Parkinson’s disease and motor fluctuations |
| Rasagaline (Azilect) | Weight loss, hypotension, dry mouth, drug interactions with other MAO inhibitors/tyramine |
| NMDA receptor inhibitor |
| Amantadine (Symmetrel) | Nausea, hypotension, hallucinations, confusion, edema | Useful for treating akinesia, rigidity, tremor, dyskinesia |