a-Adrenergic agonists such as phenylpropanolamine (PPA), ephedrine, pseudoephedrine, and phenylephrine act directly on smooth muscle receptors to
increase urethral tone and maximal urethral closure pressure. Although often more clinically effective than DES, their action is short lived, usually
requiring dosing bid-tid. Of this class of drugs, PPA is the most effective and results in fewer cardiovascular adverse effects. Previously available
in over-the-counter cold medications and appetite suppressants, it was withdrawn from the human market because of toxicity associated with overuse as
a diet aid. Ephedrine, pseudoephedrine, or phenylephrine may be tried but are less efficacious than PPA. Adverse effects of α-adrenergic drugs
include excitability, restlessness, hypertension, and anorexia.
|