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.

Nabilone (Cesamet - Lilly), a synthetic cannabinoid chemically related to tetrahydrocannabinol (THC), the main active ingredient in marijuana, was recently marketed in the USA for oral treatment of nausea and vomiting associated with cancer chemotherapy. Oral THC itself, known generically as dronabinol (Marinol), is also commercially available as an antiemetic for cancer patients (Medical Letter, 27:97, 1985). Other drugs used for this purpose include metoclopramide (Reglan - Medical Letter, 24:67, 1982), prochlorperazine (Compazine; and others), haloperidol (Haldol; and others), and...

Ondansetron (on dan' se tron; Zofran - Glaxo), a serotonin (5-hydroxytryptamine) antagonist, was recently marketed in the USA for intravenous use to prevent nausea and vomiting due to cancer chemotherapy. An oral formulation is available in many other countries.

Several currently available antiemetic drugs can prevent vomiting caused by cancer chemotherapy. Anticancer drugs that cause vomiting are listed in the table below.

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.

The FDA has approved Diclegis (Duchesnay), a fixed-dose, delayed-release combination of the H1-antihistamine doxylamine and the vitamin B6 analog pyridoxine, for treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management. It is only available by prescription. Doxylamine and pyridoxine, both currently available over the counter, were previously available by prescription in a fixed-dose combination (Bendectin) for morning sickness. Bendectin was voluntarily withdrawn in the US in 1983 because of claims of teratogenicity that have since been...

Granisetron, a serotonin (5-HT) antagonist similar to ondansetron, was recently approved by the US Food and Drug Administration for prevention of nausea and vomiting due to cancer chemotherapy. Although available in an oral formulation in other countries, granisetron is available here only for intravenous (IV) use.

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.

Older patients are especially susceptible to drug-induced cognitive impairment. They are more likely to be taking multiple drugs, to have higher blood levels of those drugs because of renal or hepatic dysfunction, and to have pre-existing cognitive problems that make it difficult to detect the role of drugs causing new symptoms or making old ones worse.

The FDA has approved valbenazine (Ingrezza – Neurocrine Biosciences), a vesicular monoamine transporter 2 (VMAT2) inhibitor, for treatment of tardive dyskinesia in adults. It is the first drug to be approved in the US for this indication; two other VMAT2 inhibitors, tetrabenazine (Xenazine, and generics) and deutetrabenazine (Austedo), were approved earlier for treatment of chorea associated with Huntington's disease.