Drug therapy for Parkinson’s disease: An update

Table 1 Currently available dopaminergic receptor agonists

Drug	D-receptor specificity	Dose range	Side effects
Ergot derivatives
Bromocryptine	D2 receptor agonist with partial dopamine D1 antagonist activity	7.5-15 mg/d orally	Risk of developing valvular regurgitation (cumulative and dose-dependent)
Lisuride	D2 receptor agonist (also has a weak dopamine D1 antagonistic, serotonin 5-HT1A agonistic, and 5-HT2B receptor antagonist properties)	0.2-3 mg/d orally	Dry mouth, nausea, weakness, postural hypotension, and headache
Cabergoline	D1 and D2 receptor agonist	0.5-4 mg/d orally	Risk of developing moderate to severe valvular regurgitation
Non-ergot derivatives
Piribedil	D2/D3 receptor agonist with alpha(2) antagonist properties	150-300 mg/d orally
Rotigotine transdermal patch	D1, D2, and D3 receptor agonist	2-16 mg patch/d	Patch site reactions, nausea, vomiting, dry mouth, somnolence , peripheral edema, and dyskinesia
Ropinirole (immediate and extended release)	D2/D3 receptor agonist	4-24 mg/d orally	Nausea, dyspepsia, dizziness, back pain, headache, uncontrollable sleep attacks, orthostatic hypotension, leg oedema
Pramipexole (immediate and extended release)	D2/D3 receptor agonist	0.25 - 4.5/d orally (Extended release pramipexole is approved as monotherapy in early PD, as well as an adjunct therapy to levodopa in advanced PD	Somnolence, cognitive adverse events, fatigue, nausea, constipation, and peripheral oedema
Apomorphine	D1 and D2 receptor agonist (also stimulates serotonin and α-adrenergic receptors)	4 mg subcutaneously 20 mg continuously daily via a pump system	Local inflammation and granuloma at the subcutaneously infusion site Intravascular thrombotic complications secondary to apomorphine crystal accumulation after iv administration

iv: Intravenous.