1736. Anticholinergic side effects include dry mouth, blurred vision, constipation, urinary retention, tachycardia, hallucinations, ataxia, mental slowing, confusion, and memory impairment. Anticholinergic drugs should be used with caution in patients with narrow-angle glaucoma, as they can increase intraocular pressure and may precipitate an acute glaucoma attack.
1737. Anticholinergic drugs are equally effective as a group, but their use is limited by their anticholinergic side effects and reduced effectiveness against bradykinesia.
1738. Drugs that are used to treat parkinsonism are pergolide and bromocriptine, which directly stimulate dopamine receptors. Levodopa is converted to dopamine in the brain; amantadine stimulates the presynaptic release of dopamine; and selegiline inhibits MAO-B and prevents the breakdown of dopamine in the brain. Pramipexole and ropinirole are non-ergot dopamine agents, and tolcapone and entacapone, COMT inhibitors, delay the breakdown of dopamine in the brain.
1739. Dopa-decarboxylase converts levodopa to dopamine, but this reaction is important to happen inside the brain. If the patient is taking pyridoxine (B6), which is a coenzyme for dopa-decarboxylase, that means more levodopa is converted to dopamine peripherally, so less dopamine in the brain.
1740. For the on-off therapy of levodopa for parkinsonism, the use of pramipexole or ropinirole has shown effectiveness as a adjunctive therapy.