Naphazoline/pheniramine

Naphazoline/pheniramine, sold under the brand name Naphcon-A among others, is a combination eye drop used to help the symptoms of allergic conjunctivitis such as from hay fever.^[1] It contains naphazoline and pheniramine.^[1][2] It is used as an eye drop.^[2] Use is not recommended for more than three days.^[3]

Naphazoline/pheniramine

Combination of
Naphazoline	Vasoconstrictor
Pheniramine	Antihistamine
Clinical data
Trade names	Naphcon-A, Opcon-A, Visine-A, others
AHFS/Drugs.com	Multum Consumer Information
Routes of administration	Eye drop
Legal status
Legal status	US: OTC
Identifiers
CAS Number	132-20-7

Side effects may include allergic reactions, eye pain, and dilated pupils.^[1][4][3] It is unclear if use in pregnancy is safe.^[2] Nephazoline works by resulting in constriction of blood vessels thus decreasing redness while pheniramine works by blocking the effects of histamine to stop itching.^[2]

The combination was approved for medical use in the United States in 1994.^[5][6][2] It is available over the counter.^[5][6][1] In 2017, it was the 203rd most commonly prescribed medication in the United States, with more than two million prescriptions.^[7][6]

Medical use

It is administered topically with one to two drops applied to the affected eye(s) up to four times daily.^[1]

Adverse effects

• Pupils may become enlarged temporarily
• Overuse may cause more redness
• Those with heart disease, high blood pressure, narrow angle glaucoma or who have urination trouble are discouraged from using the product
• It is recommended to remove contact lenses before use. Use with contact lenses can lead to reduced oxygenation of the underlying cornea
• If infants or children accidentally ingest the drops, it may lead to coma and significant reduction in body temperature. If such ingestion occurs, immediately calling a poison control center is recommended^[1]