Phenylephrine🔊

What is Phenylephrine for?

Phenylephrine is a vasoconstrictor which can constrict your blood vessels to decrease swelling and therefore can be used as a decongestant. It can be used to treat nasal congestion in cold, flu or allergies, and mydriasis (dilation of the eye pupils). Phenylephrine is usually combined with painkillers like Paracetamol and antihistamines like Chlorpheniramine in many cold and cough medicines.

How to use it?

Phenylephrine can be taken by mouth or applied to eyes or nose. The dosages for different uses, routes and age groups are listed below: 

For nasal congestion

By mouth

Adult 

10 mg every 4 hours as needed for at most 7 days. The maximum daily dose is 60 mg. 

Apply to the nose 

Adult 

Instill 0.25-1% nasal drops or spray into nostrils every 4 hours if necessary. 

Child 2-6 years 

Instill 2-3 drops 0.125% or 0.16% nasal drops into nostrils every 4 hours if necessary. 

Child 6-12 years 

Instill 2-3 drops or 1-2 sprays 0.25% solution nasal drops or spray into nostrils every 4 hours if necessary. 

For mydriasis (dilation of the eye pupils)

Apply to the eyes 

Adult 

Instill 1 drop 10% Phenylephrine hydrochloride or less to the eyes. You may repeat in 10-60 minutes if necessary. An anaesthetic should be instilled into the eyes a few minutes before instilling Phenylephrine to avoid irritation.

What are the side effects of Phenylephrine? 

Common side effects of Phenylephrine include stomach upset, dizziness, headache, tremors, trouble sleeping and nervousness.

Where to buy Phenylephrine in Hong Kong?

In Hong Kong, Phenylephrine is an over-the-counter medicine and can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.