Drug information of Phenylpropanolamine


Drug group: Decongestants

Phenylpropanolamine is a decongestant. It works by constricting (shrinking) blood vessels (veins and arteries) in your body. Constriction of blood vessels in your sinuses, nose, and chest allows drainage of those areas, which decreases congestion.

Mechanism of effect

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.


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.this drug increased risk of hemorrhagic stroke in women.


Absorption: Reduced bioavailability (about 38%) from gastrointestinal tract because of first pass metabolism by monoamine oxidase in the stomach and liver.

Metabolism: Hepatic

Half life:2.1 to 3.4 hours.

Drug indications

Obesity , nasal stuffiness


Usual Adult Dose for Nasal Congestion:

25 mg orally every 4 hours.


75 mg orally extended release every 12 hours.

Not to exceed 150 mg/day.

Usual Adult Dose for Weight Loss:

25 mg orally 3 times a day, one-half hour before meals.


75 mg orally extended release once a day in the morning.

The use of phenylpropanolamine for weight loss should be limited to 12 weeks.

Usual Pediatric Dose for Nasal Congestion:

2 to 6 years:

6.25 mg orally every 4 hours. Maximum daily dose is 37.5 mg.

6 to 12 years:

12.5 mg orally every 4 hours. Maximum daily dose is 75 mg.

> 12 years:

25 mg orally every 4 hours.


75 mg orally extended release every 12 hours.

Not to exceed 150 mg/day.


Phenylpropanolamine has been associated with an increased risk of hemorrhagic stroke (bleeding into the brain or into tissue surrounding the brain) in women. Men may also be at risk. Although the risk of hemorrhagic stroke is low, the U.S. Food and Drug Administration (FDA) recommends that consumers not use any products that contain phenylpropanolamine.

Do not take phenylpropanolamine for longer than 7 days if your condition does not improve or if your symptoms are accompanied by a high fever.

Use caution when driving, operating machinery, or performing other hazardous activities. Phenylpropanolamine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.

Points of recommendation

  • Take phenylpropanolamine exactly as directed by your doctor, or follow the instructions that accompany the package. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.
  • Take each dose with a full glass of water.
  • Never take this medication in larger doses or more often than is recommended. Too much phenylpropanolamine could be very harmful.
  • If your symptoms are accompanied by a high fever, or if they do not improve in 7 days, see your doctor.
  • Store phenylpropanolamine at room temperature away from moisture and heat.

Pregnancy level


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