Summer heat waves cause thousands of cases of heat-related illness in the USA each year and hundreds of heat-related deaths, especially among the elderly. A few principles may be helpful in preventing and treating heat injury.

Soft contact lenses have been in use for more than 20 years. Since the last Medical Letter review (vol. 24, page 109, 1982), new products have been developed, and some problems have emerged.

Nafarelin acetate (Synarel - Syntex), a synthetic analog of gonadotropin-releasing hormone (GnRH), was recently approved by the US Food and Drug Administration for treatment of endometriosis. The drug is available only in a nasal spray formulation.

Controlled-release carbidopa/levodopa (Sinemet CR - Dupont Pharma) was recently approved by the US Food and Drug Administration for treatment of Parkinson's disease. The new formulation of this old combination (Sinemet) has the drugs suspended in a polymeric matrix that erodes slowly in the gastrointestinal tract.

Sertraline (Zoloft - Roerig), a serotonin reuptake inhibitor, was recently approved for marketing by the US Food and Drug Administration for treatment of depression. Another serotonin reuptake inhibitor, fluoxetine (Prozac), is prescribed more frequently in the USA than any other antidepressant (Medical Letter, 32:83, 1990).

Finasteride (Proscar - Merck) has now been approved by the US Food and Drug Administration (FDA) for oral treatment of benign prostatic hyperplasia. A 4-aza-steroid, the drug is a specific inhibitor of steroid 5 -reductase, the enzyme that catalyzes conversion of testosterone to dihydrotestosterone. Dihydrotestosterone is required for development and maintenance of prostatic hypertrophy (JS Tenover, Endocrinol Metab Clin North Am, 20:893, 1991).

Sotalol (hydrochloride (Betapace -Berlex; Sotacor -Bristol Laboratories of Canada), an antiarrhythmic drug that prolongs repolarization (Class III) and also has beta-adrenergic-blocking activity (Class II), was recently approved by the US Food and Drug Administration (FDA) for oral treatment of life-threatening ventricular arrhythmias.

Tacrine hydrochloride (Cognex - Parke-Davis), an acridinamine derivative, will soon be available for treatment of cognitive deficits associated with Alzheimer's disease.

An intrathecal formulation of the muscle relaxant baclofen (Lioresal Intrathecal - Medtronic) has been approved by the US Food and Drug Administration for treatment of spasticity due to multiple sclerosis (MS) or spinal cord injury. Its use requires subcutaneous implantation of a drug pump, which infuses the drug into the subarachnoid space. Baclofen (Lioresal [Ciba-Geigy], and others) has been available as an oral formulation for many years (Medical Letter 20:43, 1978), but its use has been limited by central-nervous-system effects such as drowsiness and confusion.

Fluvoxamine (Luvox - Solvay), a selective serotonin reuptake inhibitor (SSRI), has been approved for treatment of obsessive-compulsive disorder (OCD) by the US Food and Drug Administration. Fluoxetine (Prozac), another SSRI antidepressant, and clomipramine (Anafranil), a tricyclic antidepressant that also inhibits serotonin reuptake, are the only other drugs available for this indication in the USA. Antidepressants that do not inhibit serotonin reuptake have not been effective for treatment of this condition.