Raloxifene hydrochloride.

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and therapeutic role of raloxifene hydrochloride are reviewed. Raloxifene is a selective estrogen-receptor modulator (SERM) that has been approved for use in the prevention and treatment of osteoporosis in postmenopausal women. A SERM interacts with estrogen receptors, functioning as an agonist in some tissues and an antagonist in other tissues. Because of their unique pharmacologic properties, these agents can achieve the desired effects of estrogen without the possible stimulatory effects on the breasts or uterus. Raloxifene is rapidly absorbed from the gastrointestinal tract and undergoes extensive first-pass glucuronidation. Approximately 60% of a dose is absorbed; however, absolute bioavailability is only 2%. The volume of distribution is 2348 L/kg for a single oral dose of 30-150 mg, and the elimination half-life averages 32.5 hours. In clinical trials in postmenopausal women, raloxifene had an estrogen-like effect on bone turnover and increased bone mineral density. It reduced the risk of fractures in women with osteoporosis. Raloxifene also seemed to reduce the risk of breast cancer and positively influenced blood lipid markers of cardiovascular disease. Raloxifene is generally well tolerated; the most common adverse effects are hot flashes and leg cramps. A serious adverse effect is venous thromboembolism. The recommended dosage is 60 mg/day orally without regard to meals. Ultimately, it will be information on cardiovascular or breast cancer benefits that will determine the future role of raloxifene. Raloxifene is an alternative to traditional hormone replacement therapy for the prevention and treatment of osteoporosis in selected postmenopausal women. More study is needed to verify possible benefits related to heart disease and breast cancer.

Troglitazone in type II diabetes mellitus.

Troglitazone, a new antihyperglycemic agent, is approved for use alone, with oral sulfonylureas, or with insulin in the treatment of type II diabetes mellitus. Rather than stimulating insulin secretion, it enhances insulin sensitivity. Potential advantages of troglitazone over oral sulfonylureas include decreased endogenous insulin concentrations, decreased exogenous insulin requirements, reduced hypoglycemic risk, and convenient once/day administration. The effect on morbidity and mortality from lowering endogenous and exogenous insulin concentrations remains to be determined. Troglitazone also has potential disadvantages. It induces cytochrome P450 isoenzyme 3A4, although few drug interactions have been identified to date. Serum transaminases must be monitored routinely because of rarely reported cases of idiosyncratic hepatocellular injury. In addition, the cost of troglitazone is much higher than that of other oral antihyperglycemic agents or insulin. Given the available information, troglitazone has limited benefit over oral sulfonylureas or metformin as monotherapy or in combination with oral sulfonylureas. Until additional combination and comparative studies have been done, the agent should be reserved for patients with poor glycemic control receiving high daily doses of insulin.