| Antiparkinsonian Agents | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Levodopa | Most effective for symptomatic relief | Dyskinesia after 5 to 10 years of treatment, On-off syndrome, nausea, vomiting, anorexia, hypotension, dystonia, dyskinesia, confusion |
| Carbidopa | Improves Levodopa effectivity; prevents its metabolism before reaching the brain | |
| Anticholinergic Agents | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Trihexyphenidyl hydrochloride | Control of tremor in patients with early onset disease | Blurred vision, flushing, rash, constipation, urinary retention, and acute confusional states |
| Benztropine mesylate | Counteract the action of acetylcholine | Contraindicated in patients with narrow-angle glaucoma |
| Antiviral Agents | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Amantadine hydrochloride | Reduce rigidity, tremor, bradykinesia, and postural changes in early Parkinson’s disease (PD) | Psychiatric disturbances (mood changes, confusion, depression, hallucinations), lower extremity edema, nausea, epigastric distress, urinary retention, headache, and visual impairment |
| Dopamine Agonists | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Bromocriptine Mesylate | Early PD as well as secondary drug therapy after carbidopa or levodopa loses effectiveness | Nausea, vomiting, diarrhea, lightheadedness, hypotension, impotence, and psychiatric effects |
| Pergolide | | |
| Nonergot Derivatives | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Ropinirole hydrochloride | Early stages of PD | May cause drowsiness or dizziness |
| Pramipexole | | |
| Monoamine Oxidase-Inhibitors | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Selegiline | Inhibit dopamine breakdown | Agitation, dizziness, nausea, headache, rhinitis, back pain, stomatitis, orthostatic hypotension, insomnia |
| Rasagiline | | |
| Catechol-O-Methyltransferase Inhibitors | Indications and Therapeutic Effects | Common Side Effects |
|---|
| Entacapone | Increase the duration of action of carbidopa or levodopa. | Abdominal pain, back pain, constipation, nausea, diarrhea, hematouria |
| Tolcapone | Reduce motor fluctuations in patients with advanced PD | |