Yohimbine hydrochloride, a presynaptic 2 -adrenergic receptor antagonist available by prescription in the USA (Yocon, Yohimex, and others), is advertised for treatment of impotence and has been used as an aphrodisiac. A pre-1938 drug, yohimbine has never been approved for marketing by the US Food and Drug Administration.

Thalidomide is now available as an investigational drug in the USA. A synthetic derivative of glutamic acid, it was marketed in Europe in 1957 as a sedative but withdrawn four years later after being associated with severe human teratogenicity (PF DArcy and JP Griffin, Adverse Drug React Toxicol Rev, 13:65, 1994). The drug has since been found effective for several different indications.

The FDA has approved Nuedexta (Avanir), a fixed-dose combination of the cough suppressant dextromethorphan hydrobromide and the antiarrhythmic quinidine sulfate, for oral treatment of pseudobulbar affect. The combination is the first treatment approved by the FDA for this indication. Studies to support the effectiveness of Nuedexta were performed in patients with underlying amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS); the drug has not been shown to be safe or effective in other types of emotional lability.

The drugs of choice for treatment of common cardiac arrhythmias are listed in Tables 1 and 2. Some drugs are recommended for indications that have not been approved by the FDA.

An oral formulation of mesalamine (5-aminosalicylic acid, 5-ASA, Asacol - Proctor & Gamble), was recently approved by the US Food and Drug Administration (FDA) for treatment of mildly to moderately active ulcerative colitis; it has not been approved for maintenance of remissions. Olsalazine (Dipentum), a similar drug (Medical Letter, 32:105, 1990), is approved for maintenance of remissions but not for treatment.

Two products combining conjugated estrogens with medroxyprogesterone acetate (Prempro and - Wyeth-Ayerst) were recently approved for marketing by the US Food and Drug Administration. Both combine in one package tablets of Premarin, a conjugated equine estrogen product, with tablets of Cycrin, a medroxyprogesterone acetate brand. With Prempro, both tablets are taken daily continuously; with Premphase, the estrogen is taken daily, but the progestin is taken sequentially on days 15 through 28 of each 28-day cycle.

Infliximab, a monoclonal antibody that inhibits tumor necrosis factor, has received an accelerated approval from the FDA for intravenous treatment of moderate to severe Crohn's disease refractory to other medical treatment.

View Expanded Table: Some Conventional DMARDs for Rheumatoid Arthritis

Ecamsule (terephthalylidene dicamphor sulfonic acid), the first new sunscreen agent to be approved by the FDA in 18 years, is now available in the US in a moisturizer called Anthelios SX. Ecamsule has been used in Canada and Europe for more than 10 years.

Balsalazide disodium (Colazal), a prodrug of mesalamine, was marketed in the US this year for oral treatment of mildly to moderately active ulcerative colitis. Oral formulations of mesalamine have been available in the US for nine years for treatment and maintenance of remissions and olsalazine, which is a dimer of mesalamine, is marketed for maintenance of remissions but not for treatment. Balsalazide has been available in Europe for four years.