"The U.S. Food and Drug Administration today proposed to withdraw approval of the drug midodrine hydrochloride, used to treat the low blood pressure condition orthostatic hypotension, because required post-approval studies that verify the clinical"...
Supine Hypertension: The most potentially serious adverse reaction associated with ProAmatine (midodrine hydrochloride) ® therapy is marked elevation of supine arterial blood pressure (supine hypertension). Systolic pressure of about 200 mmHg were seen overall in about 13.4% of patients given 10 mg of ProAmatine (midodrine hydrochloride) ® . Systolic elevations of this degree were most likely to be observed in patients with relatively elevated pre-treatment systolic blood pressures (mean 170 mmHg). There is no experience in patients with initial supine systolic pressure above 180 mmHg, as those patients were excluded from the clinical trials. Use of ProAmatine (midodrine hydrochloride) ® in such patients is not recommended. Sitting blood pressures were also elevated by ProAmatine (midodrine hydrochloride) ® therapy. It is essential to monitor supine and sitting blood pressures in patients maintained on ProAmatine (midodrine hydrochloride) ® .
General: The potential for supine and sitting hypertension should be evaluated at the beginning of ProAmatine® (midodrine hydrochloride) therapy. Supine hypertension can often be controlled by preventing the patient from becoming fully supine, i.e., sleeping with the head of the bed elevated. The patient should be cautioned to report symptoms of supine hypertension immediately. Symptoms may include cardiac awareness, pounding in the ears, headache, blurred vision, etc. The patient should be advised to discontinue the medication immediately if supine hypertension persists.
Blood pressure should be monitored carefully when ProAmatine® (midodrine hydrochloride) is used concomitantly with other agents that cause vasoconstriction, such as phenylephrine, ephedrine, dihydroergotamine, phenylpropanolamine, or pseudoephedrine.
A slight slowing of the heart rate may occur after administration of ProAmatine® (midodrine hydrochloride) , primarily due to vagal reflex. Caution should be exercised when ProAmatine® (midodrine hydrochloride) is used concomitantly with cardiac glycosides (such as digitalis), psychopharmacologic agents, beta blockers or other agents that directly or indirectly reduce heart rate. Patients who experience any signs or symptoms suggesting bradycardia (pulse slowing, increased dizziness, syncope, cardiac awareness) should be advised to discontinue ProAmatine® (midodrine hydrochloride) and should be re-evaluated.
ProAmatine® (midodrine hydrochloride) should be used cautiously in patients with urinary retention problems, as desglymidodrine acts on the alpha-adrenergic receptors of the bladder neck.
ProAmatine® (midodrine hydrochloride) should be used with caution in orthostatic hypotensive patients who are also diabetic, as well as those with a history of visual problems who are also taking fludrocortisone acetate, which is known to cause an increase in intraocular pressure and glaucoma. ProAmatine® (midodrine hydrochloride) use has not been studied in patients with renal impairment. Because desglymidodrine is eliminated via the kidneys, and higher blood levels would be expected in such patients, ProAmatine® (midodrine hydrochloride) should be used with caution in patients with renal impairment, with a starting dose of 2.5 mg (see DOSAGE AND ADMINISTRATION). Renal function should be assessed prior to initial use of ProAmatine® (midodrine hydrochloride) .
ProAmatine® (midodrine hydrochloride) use has not been studied in patients with hepatic impairment. ProAmatine® (midodrine hydrochloride) should be used with caution in patients with hepatic impairment, as the liver has a role in the metabolism of midodrine.
Carcinogenesis, Mutagenesis, Impairment of Fertility: Long-term studies have been conducted in rats and mice at dosages 3 to 4 times the maximum recommended daily human dose on a mg/m²basis, with no indication of carcinogenic effects related to ProAmatine® (midodrine hydrochloride) . Studies investigating the mutagenic potential of ProAmatine® (midodrine hydrochloride) revealed no evidence of mutagenicity. Other than the dominant lethal assay in male mice, where no impairment of fertility was observed, there have been no studies on the effects of ProAmatine® (midodrine hydrochloride) on fertility.
Pregnancy: Pregnancy Category C. ProAmatine® (midodrine hydrochloride) increased the rate of embryo resorption, reduced fetal body weight in rats and rabbits, and decreased fetal survival in rabbits when given in doses 13 (rat) and 7 (rabbit) times the maximum human dose based on body surface area (mg/m²). There are no adequate and well-controlled studies in pregnant women. ProAmatine® (midodrine hydrochloride) should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. No teratogenic effects have been observed in studies in rats and rabbits.
Nursing Mothers: It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when ProAmatine® (midodrine hydrochloride) is administered to a nursing woman.
Pediatric Use: Safety and effectiveness in pediatric patients have not been established.
Last reviewed on RxList: 10/25/2010
This monograph has been modified to include the generic and brand name in many instances.
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