The FDA has approved Gimoti (Evoke), a nasal spray formulation of the dopamine-2 (D₂) receptor antagonist metoclopramide, for relief of symptoms in adults with acute and recurrent diabetic gastroparesis. Metoclopramide (Reglan, and generics) has been available for years in conventional and orally-disintegrating tablets and in an injectable formulation. It is the only drug that is FDA-approved for treatment of diabetic gastroparesis.

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...

Changes caused by one drug in the absorption, distribution, metabolism or excretion of another may lead to a pharmacokinetic adverse drug interaction (DN Juurlink et al, JAMA 2003; 289:1652). Additive drug interactions, such as vasodilation caused by both sildenafil (Viagra) and nitrates, can also have adverse effects.

Cisapride (Propulsid - Janssen), a piperidinyl benzamide prokinetic drug, is now available in the USA for symptomatic relief of nocturnal heartburn due to gastroesophageal reflux disease. In Canada, cisapride is also marketed for treatment of gastroparesis.