These are two common ingredients in nonprescription cold and allergy medicines, such as Sudafed and Sudafed PE.

Which Works Better?

However, the Food and Drug Administration (FDA) is considering removing phenylephrine from the marketplace.

Older couple taking medication at home while reviewing medical instructions

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What Makes Phenylephrine Ineffective?

Oral phenylephrine’s ineffectiveness is due to its low bioavailability.

This means most of the drug is not effectively used by the body.

How Does Pseudoephedrine Work?

It also helps to decrease mucus production.

As a result, it relieves swelling and congestion, making it easier to breathe through your nose.

Due to the regulations mentioned, you’re free to only buy pseudoephedrine in-store.

Note, however, that pseudoephedrine products usually are not covered by prescription insurance plans.

Higher doses may cause additional or more severe side effects.

Who Should Avoid Them?

Decongestants are not safe for everyone.

Certain people should avoid taking phenylephrine, pseudoephedrine, or both.

These medications are generally not recommended during pregnancy.

Interactions

Both pseudoephedrine and phenylephrine can interact with certain medications.

These can potentially interact with phenylephrine or pseudoephedrine as well.

Can You Take Them Together?

Taking pseudoephedrine and phenylephrine at the same time is not recommended.

While both ingredients are found in OTC products, pseudoephedrine is available behind the pharmacy counter due to regulations.

Food and Drug Administration.Key information about nonprescription, over-the-counter (OTC), oral phenylephrine.

In:Mother To Baby | Fact Sheets.

Brentwood (TN): Organization of Teratology Information Specialists (OTIS); March 2024.

MedlinePlus.High blood pressure - medicine-related.