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Tuesday July 21 1:17 PM EDT New drug helps orthostatic hypotension NEW YORK, Jul 21 (Reuters) -- A new drug called midodrine can help patients with neurogenic orthostatic hypotension -- a fall in blood pressure on standing up due to neurological causes, according to a study in the July issue of Neurology. People with neurogenic orthostatic hypotension have normal, or even high, blood pressure when lying down. But their blood pressure drops precipitously when they stand. The sudden drop can cause dizziness and fainting. A number of conditions, including PARKINSON'S disease, can cause orthostatic hypotension. So can nerve damage due to diabetes. The US Food and Drug Administration recently approved midodrine, which is taken orally, for neurogenic orthostatic hypotension. To determine the smallest effective dose of the drug, and to investigate possible side effects at this dose, the study's authors tested midodrine among 25 people with the condition. The researchers found that a10 milligram (mg) dose of midodrine, two to three times daily, effectively treated symptoms and caused few side effects. The drug, which has the brand name Proamatine, boosted blood pressure within an hour, they found. And its effects lasted about 4 hours. A 10 mg dose caused only minor side effects, including goose bumps, tingling and itching, the researchers report. "This is an important step for people with orthostatic hypotension," the study's senior author, Dr. Philip A. Low, of the Mayo Clinic in Rochester, Minnesota, told Reuters Health in an interview. Doctors have long prescribed a drug called fludrocortisone for people with orthostatic hypotension, even though it is not officially approved for this use, Low said. Fludrocortisone boosts blood pressure and, consequently, prevents sudden drops in blood pressure upon standing. A drawback with fludrocortisone, however, is that its effects last for days. Since patients with orthostatic hypotension have normal or high blood pressure while lying down, the drug causes high blood pressure at night, when patients are sleeping. Since midodrine takes effect within an hour, and its effects last only 4 hours, patients can take it in the morning and again in the afternoon and get an immediate boost. By the time bedtime rolls around, though, the effects will have worn off, so nighttime high blood pressure should not be such a problem, Low said. "Midodrine is best used in the morning and preceding physical activity, and it should be avoided before bedtime," he and colleagues conclude. Some patients taking fludrocortisone should be able to switch to midodrine alone, Low said. Others will probably have to continue taking fludrocortisone .By adding midodrine, though, they should be able to take a smaller dose of fludrocortisone, Low said. The study received funding from Roberts Pharmaceutical Corporation, of Eatontown, New Jersey; NASA; and the Mayo Clinic, Rochester, Minnesota. SOURCE: Neurology 1998;51:120-124. -- Judith Richards, London, Ontario, Canada [log in to unmask]