Regitine®
C98-25 665490
Regitine ®
phentolamine mesylate for injection, USP
Vials
Rx only
Prescribing Information
DESCRIPTION
Regitine, 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 4,5-dihydro-2-[N-(m -hydroxyphenyl)-N-(p -methylphenyl) aminomethyl]-1 H -imidazole 1:1 methanesulfonate, and its structural formula is
Phentolamine mesylate for injection, USP, is a white or off-white, odorless crystalline powder with a molecular weight of 377.46. Its solutions are acid to litmus. It is freely soluble in water and in alcohol, and slightly soluble in chloroform. It melts at about 178ºC.
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CLINICAL PHARMACOLOGY
Regitine 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.
Regitine 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.
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