The main purpose of vasopressors is to raise arterial blood pressure, while that of inotropes is to increase cardiac contractility. The choice of drugs is dictated by the clinical setting. Controlled trials comparing the efficacy and safety of these drugs are generally lacking.

Pramipexole (Mirapex - Pharmacia & Upjohn) and ropinirole (Requip - SmithKline Beecham), two new dopamine agonists, have been approved by the US Food and Drug Administration (FDA) for treatment of both early (without levodopa) and advanced (with levodopa) Parkinson's disease. Bromocriptine (Parlodel) and pergolide (Permax) are older dopamine agonists marketed in the USA for adjunctive use with levodopa.

The dopamine agonist pramipexole (Mirapex - Boehringer Ingelheim) is the second drug approved by the FDA for treatment of moderate to severe restless legs syndrome (RLS). Ropinirole (Requip), another dopamine agonist, was approved for RLS in 2005. Both of these drugs were first approved for treatment of Parkinson's disease.

Recent articles in the press have trumpeted a new era in the management of Parkinson's disease: dopamine agonists have now replaced levodopa for initial treatment.

Ropinirole (Requip - GlaxoSmithKline), a dopamine agonist already available for treatment of Parkinson's disease, is now the first drug approved by the FDA for treatment of moderate to severe restless legs syndrome (RLS).

The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems. No disease-modifying drugs are available for treatment of PD.

Rotigotine (Neupro - Schwarz Pharma), a nonergot dopamine agonist in a transdermal patch formulation, was recently approved by the FDA for treatment of early Parkinson's disease (PD).

Apomorphine (Apokyn - Mylan/Bertek), an injected non-ergot dopamine agonist, was recently approved by the FDA for intermittent subcutaneous (SC) treatment of hypomobility ("off" episodes) in patients with advanced Parkinson's disease. It has been available in Europe for many years.

Levodopa combined with carbidopa (Sinemet) is the treatment of choice for Parkinson's disease (Medical Letter, 30:113, 1988). After prolonged treatment, however, the symptoms of the disease often become difficult to manage. The benefit from each dose becomes shorter (the 'wearing-off' effect), sudden fluctuations occur between mobility and immobility (the 'on-off' phenomenon), and abnormal involuntary movements (dyskinesias) may become frequent. The dopamine agonist bromocriptine (Parlodel) can ameliorate some of these effects. Two new drugs, pergolide (Permax - Lilly), another dopamine...

The FDA has approved solriamfetol (Sunosi – Jazz), a dopamine and norepinephrine reuptake inhibitor (DNRI), to improve wakefulness in adults with excessive daytime sleepiness (EDS) associated with narcolepsy or obstructive sleep apnea (OSA). Pitolisant (Wakix), an H3-receptor antagonist/inverse agonist recently approved by the FDA for treatment of excessive daytime sleepiness in patients with narcolepsy, will be reviewed in a future issue.