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What is the most important information I should know about phenylephrine?

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

Do not use more of this medication than is recommended on the package or by your doctor. Too much medication could be harmful Use caution when driving, operating machinery, or performing other hazardous activities. Phenylephrine may cause dizziness, drowsiness, or impaired concentration. If you experience dizziness, drowsiness, or impaired concentration, avoid these activities.

What is phenylephrine?

Phenylephrine is a decongestant. It works by constricting (shrinking) blood vessels (veins and arteries). Constriction of blood vessels in the sinuses, nose, and chest allows drainage of these areas, which decreases congestion. Constriction of blood vessels also affects blood pressure.

When taken by mouth, phenylephrine is used to treat congestion associated with allergies, hay fever, sinus irritation, and the common cold. When used by injection, phenylephrine is used to maintain adequate blood pressure and to treat certain types of irregular heartbeats.

Phenylephrine may also be used for purposes other than those listed in this medication guide.

What should I discuss with my healthcare provider before taking phenylephrine?

Do not use phenylephrine if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction leading to serious side effects could occur.

Before using this medication, tell your doctor if you have

• high blood pressure;

• heart disease, hardening of the arteries, or irregular heartbeats;

• thyroid problems;

• diabetes;

• glaucoma or increased pressure in the eye(s);

• an enlarged prostate or difficulty urinating;

• liver disease; or
• kidney disease.

You may not be able to use phenylephrine, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.

Phenylephrine is in the FDA pregnancy category C. This means that it is not known whether it will harm an unborn baby. Do not use this medication without first talking to your doctor if you are pregnant. Phenylephrine may pass into breast milk and affect a nursing baby. Do not use this medication without first talking to your doctor if you are breast-feeding a baby. If you are over 60 years of age, you may be more likely to experience side effects from phenylephrine. You may require a lower dose of this medication.