When initiating therapy with phenylpropanolamine, it is important not to expect an immediate change in urinary incontinence. Several days of proper dosing will be needed before effect can be assessed. Before using phenylpropanolamine to control urinary incontinence, it is important to rule out other medical causes of incontinence such as kidney disease and bladder infection. These latter conditions are progressive and should be identified early in their course for meaningful treatment results. Phenylpropanolamine should be stored in containers which protect it from light.
Light exposure leads it to lose potency.
Phenylpropanolamine acts by causing the release of a hormone and neurotransmitter called norepinephrine. With chronic use, it is possible to deplete the body s stores of norepinephrine and the patient will appear to become resistent to the effects of the drug. This phenomenon is well described in people who use phenylpropanolamine as a decongestant but it is unclear as to whether this occurs in dogs and cats. Because of its effects in elevating heart rate and blood pressure, phenylpropanolamine should not be used in patients with heart disease or pre-existing high blood pressure. This includes patients with glaucoma, hyperthyroidism, and diabetes mellitus as well as those with certain types of cardiovascular disease.