PHENTOLAMINE MESYLATE- phentolamine mesylate injection, powder, for solution
Bedford Laboratories
Rx ONLY.
DESCRIPTION
Phentolamine Mesylate for Injection USP, is an antihypertensive, available in vials for intravenous and intramuscular administration. Each vial contains phentolamine mesylate USP, 5 mg and mannitol USP, 25 mg in sterile, lyophilized form.
Phentolamine mesylate is m -[N -(2-Imidazolin-2-ylmethyl)-p -toluidino]phenol monomethanesulfonate (salt),
Molecular Formula � C17 H19 N3 O�CH4 O3 S M.W. � 377.47
Phentolamine mesylate USP is a white or off-white, odorless crystalline powder. Its solutions are acid to litmus. It is freely soluble in water and in alcohol, and slightly soluble in chloroform. It melts at about 178�C.
CLINICAL PHARMACOLOGY
Phentolamine mesylate produces an alpha-adrenergic block of relatively short duration. It also has direct, but less marked, positive inotropic and chronotropic effects on cardiac muscle and vasodilator effects on vascular smooth muscle.
Phentolamine has a half-life in the blood of 19 minutes following intravenous administration. Approximately 13% of a single intravenous dose appears in the urine as unchanged drug.
INDICATIONS AND USAGE
Phentolamine Mesylate for Injection is indicated for the prevention or control of hypertensive episodes that may occur in a patient with pheochromocytoma as a result of stress or manipulation during preoperative preparation and surgical excision.
Phentolamine Mesylate for Injection is indicated for the prevention or treatment of dermal necrosis and sloughing following intravenous administration or extravasation of norepinephrine.
Phentolamine Mesylate for Injection is also indicated for the diagnosis of pheochromocytoma by the phentolamine blocking test.
