Pseudoephedrine (Sudafed) is categorized as an alpha-receptor agonist and is used to treat incontinence.

Alpha-receptors are found in many parts of the body including the area around the bladder neck and prostatic capsule.  Receptors are neurological sites on which specific neurotransmitters attach.  An agonist acts to accentuate or stimulate a receptor leading to the activity associated with that receptor.  Conversely, a receptor blocker inhibits or prevents action occurring when a receptor is activated.

Stimulation of alpha-receptors at the level of the bladder neck can create increased resistance to urine flow.  In the case of stress incontinence there can be a decrease in leakage in some patients.  However there are some issues with use of pseudoephedrine.  Because other alpha-receptors in the body are stimulated with pseudoephedrine side effects such as hypertension and headaches can occur.  Also, in men with some degree of bladder obstruction by the prostate, the increased tone at the bladder neck can interfere with emptying.