Non-selective alpha blockers 

Non-selective alpha blockers like phenoxybenzamine and phentolamine are particularly used to control hypertension that may be produced during surgical removal of adrenal gland in pheochromocytoma. Even these drugs produce vasodilatation still they are not preferred as conventional anti-hypertensives due to pronounced side effects like postural hypotension and tachycardia.
#phenoxybenzamine
#irreversible
#phentolamine