Phentolamine is a medication that functions as a competitive α-adrenergic receptor antagonist. It is primarily used to treat severe hypertensive states caused by excessive levels of catecholamines, such as pheochromocytoma, clonidine withdrawal, and crack + some more technical info. Phentolamine produces nonselective blockade at both alpha 1 and alpha 2 receptors, leading to arterial and venous vasodilation, decreased peripheral resistance, and potential reflex tachycardia; this pharmacology underlies its intravenous use in acute catecholamine mediated hypertensive emergencies and its local use to reverse vasopressor extravasation. Clinically relevant technical points include rapid onset after IV administration, a relatively short duration of action supporting titratable control in acute settings, hepatic metabolism with subsequent renal excretion of metabolites, and known interactions with other vasoactive agents that may potentiate hypotension. Standard clinical preparations include the mesylate salt for parenteral use and formulations for local infiltration in tissue ischemia; dosing must be individualized with close hemodynamic monitoring due to variable patient response.
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Parent: Phentolamine
Typical quality control profiles for phentolamine active pharmaceutical ingredient list related organic impurities and degradants characterized by HPLC or LCMS, including positional phenyl isomers, N-oxidation products, and low level polymeric or dimeric species; individual identified related compounds are commonly controlled to limits in the range of 0.1 to 0.5 percent by weight, with a total related substances limit commonly set at 0.5 to 1.0 percent by weight depending on the specification and regulatory requirement. Other routine specifications include residual solvents within ICH limits—for example methanol and ethanol controlled to parts per million thresholds appropriate to their class—water content determined by Karl Fischer typically below 1.5 percent, and heavy metals controlled to pharmacopeial limits often expressed in parts per million. Manufacturers will define acceptance criteria and analytical methods in the master specification; stability studies guide allowable impurity increases over shelf life.
Phentolamine is used primarily to manage acute hypertensive episodes caused by excess catecholamines such as pheochromocytoma crises, hypertensive emergencies associated with clonidine withdrawal, and catecholamine surges from stimulant use, and it is also used locally to treat vasopressor extravasation and to aid in diagnostic testing for catecholamine secreting tumors.
Yes, phentolamine is an alpha adrenergic blocker that antagonizes alpha 1 receptors; it is nonselective and also blocks alpha 2 receptors.
Phentolamine is often supplied as phentolamine mesylate in pharmaceutical formulations and may be referred to by that salt name in product labeling.
Yes, phentolamine can be used intravenously for hypertensive crises driven by excessive catecholamines and in specific clinical situations where alpha blockade is indicated, provided careful hemodynamic monitoring is in place.
