| Indication | For the treatment of nasal congestion, control of urinary incontinence, priapism and obesity. |
| Pharmacodynamics | Phenylpropanolamine (PPA), a sympathomimetic agent structurally similar to pseudoephedrine, is used to treat nasal congestion. Phenylpropanolamine is found in appetite suppressant formulations and with guaifenesinin in cough-cold formulations. In 2000, the FDA requested that all drug companies discontinue marketing products containing phenylpropanolamine, due to an increased risk of hemorrhagic stroke in women who used phenylpropanolamine. |
| Mechanism of action | Phenylpropanolamine acts directly on alpha- and, to a lesser degree, beta-adrenergic receptors in the mucosa of the respiratory tract. Stimulation of alpha-adrenergic receptors produces vasoconstriction, reduces tissue hyperemia, edema, and nasal congestion, and increases nasal airway patency. PPA indirectly stimulates beta-receptors, producing tachycardia and a positive inotropic effect. |
| Absorption | Reduced bioavailability (about 38%) from gastrointestinal tract because of first pass metabolism by monoamine oxidase in the stomach and liver. |
| Volume of distribution | Not Available |
| Protein binding | Not Available |
| Metabolism | Hepatic |
| Route of elimination | Not Available |
| Half life | 2.1 to 3.4 hours. |
| Clearance | Not Available |
| Toxicity | May induce ventricular extrasystoles and short paroxysms of ventricular tachycardia, a sensation of fullness in the head and tingling of the extremities; LD50=1490mg/kg (orally in rat) |
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