Phenylephrine

Nasal and Sinus Congestion

Phenylephrine is primarily used as a decongestant to provide temporary relief from symptoms caused by the common cold, hay fever, or other upper respiratory allergies. It helps reduce:

• Nasal stuffiness.
• Sinus pressure and congestion.

Medical and Hospital Use

In clinical settings, phenylephrine is used in an injectable form for specific cardiovascular needs. These include:

• Increasing blood pressure in adults with low blood pressure (hypotension) resulting from anesthesia or septic shock.
• Treating certain types of irregular heartbeats, such as paroxysmal supraventricular tachycardia.
• Assisting in regional anesthesia by acting as a vasoconstrictor to help maintain the numbing effect in a specific area.

How It Works in the Body

Phenylephrine is a type of medication called a sympathomimetic amine. It works by stimulating specific receptors, known as alpha-1 adrenergic receptors, which are found on the walls of blood vessels. When these receptors are activated, they signal the muscles in the blood vessel walls to tighten, a process called vasoconstriction.

Reducing Nasal Swelling

Nasal congestion happens when the blood vessels in the nose become swollen and enlarged due to infection or allergies. By causing these vessels to narrow, phenylephrine helps to:

• Shrink the swollen tissues inside the nasal passages.
• Open up the airways to make breathing easier.
• Reduce the amount of fluid that leaks from the vessels, which can help decrease mucus production.

Increasing Blood Pressure

When administered by a healthcare professional through an injection, phenylephrine works throughout the body to narrow blood vessels. This narrowing increases the resistance in the circulatory system, which helps raise blood pressure levels during surgery or in emergency situations where blood pressure has dropped too low.

Common Side Effects

Many people using phenylephrine do not experience significant side effects. When they do occur, common symptoms may include:

• Nervousness or restlessness
• Dizziness
• Headache
• Difficulty falling asleep or staying asleep
• Nausea or vomiting
• Temporary stinging, burning, or increased nasal discharge (with nasal forms)

Serious Side Effects

Stop using the medication and contact a healthcare provider immediately if you experience any of the following:

• Fast, pounding, or irregular heartbeat
• Severe headache or blurred vision
• Chest pain
• Difficulty breathing or shallow breathing
• Signs of an allergic reaction, such as rash, hives, or swelling of the face, lips, or throat
• Increased nasal congestion or redness inside the nose (if using nasal sprays for more than 3 days)

Medical Conditions

Consultation with a healthcare provider is recommended before using phenylephrine for individuals with the following conditions:

• Heart disease
• High blood pressure
• Thyroid disease
• Diabetes
• Trouble urinating due to an enlarged prostate gland

Drug Interactions

Phenylephrine should not be used if a person is currently taking a prescription monoamine oxidase inhibitor (MAOI), which are sometimes used for depression, psychiatric conditions, or Parkinson's disease. It should also not be used for at least two weeks after stopping an MAOI. If there is uncertainty about whether a medication contains an MAOI, a healthcare professional should be consulted.

Usage Limits and Efficacy

For nasal spray formulations, use is typically limited to no more than three days. Using nasal phenylephrine more often or for longer than directed may cause nasal congestion to recur or worsen, a condition known as rebound congestion.

The FDA has noted that recent scientific data indicates oral phenylephrine is not effective as a nasal decongestant at the standard over-the-counter dose. This finding is related to the drug's effectiveness rather than its safety.

When to Stop Use

Use should be discontinued and a doctor consulted if symptoms do not improve within seven days, if a fever occurs, or if new symptoms such as nervousness, dizziness, or sleeplessness develop.

Pregnancy

The safety of phenylephrine during pregnancy has not been established through well-controlled clinical studies in humans. Animal reproduction studies have also not been conducted for many forms of this medication. Consequently, it is unknown whether phenylephrine can cause fetal harm or affect reproductive capacity.

Some medical experts suggest caution because phenylephrine works by narrowing blood vessels, which could potentially reduce blood flow to the uterus or placenta. Because of these uncertainties, phenylephrine should generally only be used during pregnancy if a healthcare provider determines that the potential benefit justifies the potential risk to the fetus.

Breastfeeding

It is not known whether phenylephrine passes into human breast milk or if it affects the nursing infant. There is also limited information regarding whether phenylephrine may temporarily decrease the amount of breast milk produced. Because many drugs are excreted in human milk, caution should be exercised when using phenylephrine while nursing.

If you are breastfeeding or planning to breastfeed, discuss the use of phenylephrine with your doctor or pharmacist to determine the most appropriate treatment options.

Oral Formulations

Phenylephrine is commonly found in over-the-counter oral medications. These forms include:

• Tablets and capsules
• Chewable tablets
• Oral liquids, such as syrups or solutions

Nasal and Ophthalmic Formulations

For localized treatment of the nose or eyes, phenylephrine is available in the following forms:

• Nasal sprays and nasal drops
• Ophthalmic solutions (eye drops)

Injectable Formulations

In clinical or hospital settings, phenylephrine is administered as an injection. This is typically provided as a solution for intravenous injection or infusion.

Rectal Formulations

Phenylephrine is also used as an active ingredient in various topical rectal products, including:

• Ointments and creams
• Suppositories

Current Regulatory Status

Phenylephrine is currently permitted for use in over-the-counter (OTC) products under the FDA's OTC Monograph system. It is widely available in oral tablets, liquids, and nasal sprays for the temporary relief of nasal and sinus congestion. Prescription-strength injectable forms are also FDA-approved for hospital use to treat low blood pressure during anesthesia.

Proposed Changes for Oral Products

In November 2024, the FDA issued a proposed order to remove oral phenylephrine as an active ingredient from the OTC Monograph for use as a nasal decongestant. This proposal followed a review of scientific data by an advisory committee, which concluded that phenylephrine is not effective as a nasal decongestant when taken orally at the standard dose.

• Scope: The proposal only applies to oral phenylephrine (pills and liquids).
• Nasal Sprays: It does not affect phenylephrine nasal sprays, which remain effective for temporary relief.
• Safety: The proposal is not based on safety concerns; the FDA has stated that oral phenylephrine does not pose a safety risk when used as directed.

As of late 2024, the FDA has not issued a final order. Products containing oral phenylephrine may remain on store shelves and continue to be sold while the agency reviews public comments and completes the administrative process.

How it Works

Phenylephrine belongs to a class of medications known as nasal decongestants. It works by narrowing the blood vessels in the nasal passages, which reduces swelling and congestion, making it easier to breathe through the nose.

Proper Use

This medication is typically used every four hours as needed. To administer the spray:

• Gently blow your nose to clear the passages.
• Keep your head upright and insert the spray tip into one nostril.
• Squeeze the bottle quickly and firmly while sniffing in.
• Repeat the process for the other nostril.
• Wipe the tip clean after each use to prevent the spread of germs.

Important Safety Information

It is critical not to use phenylephrine nasal spray for more than three days in a row. Overuse can lead to a condition called rebound congestion, where nasal symptoms return or become worse than they were before using the medication.

Common side effects may include temporary stinging, burning, sneezing, or an increase in nasal discharge. Consult a healthcare provider before use if you have any of the following conditions:

• Heart disease
• High blood pressure
• Thyroid disease
• Diabetes
• Difficulty urinating due to an enlarged prostate gland

Stop use and contact a doctor if you experience dizziness, sleeplessness, or if your symptoms do not improve within seven days.