Phenylephrine is a medication used for a wide variety of different purposes, depending on the particular form of the product. Oral (tablet or liquid) and nasal (spray or drops) forms of the drug are used as decongestants for the following purposes:
Injectable phenylephrine is used for the following purposes:
- Increasing dangerously low blood pressure (usually in emergency situations)
- Controlling an irregular heart rhythm (arrhythmia) known as ventricular tachycardia
- Maintaining adequate blood pressure during anesthesia
- Prolonging the action of spinal anesthesia
- Limiting the "leakage" of a regional or local anesthesia to surrounding tissues (which helps limit toxicity and improves and prolongs the anesthetic action) by constricting blood vessels.
Phenylephrine eye drops are used for the following purposes:
- Dilating the eye
- Treating wide angle glaucoma
- Reducing redness of the eye.
Phenylephrine cream (which contains other active ingredients as well) is used to treat
hemorrhoids.
Phenylephrine works by stimulating certain receptors known as alpha-adrenergic receptors.
In the lining of the nose and sinuses, this action causes the blood vessels to constrict, allowing less fluid to leave the blood vessels and decreasing inflammation. This helps to relieve nasal and sinus congestion.
In the blood vessels of the body, this action causes an increase in blood pressure, which is why the medication is used in emergency situations to increase dangerously low blood pressure. In the eye, phenylephrine causes dilation of the pupil, constriction of the blood vessels, and a decongestant action.
