Indications
Tetryzoline Hydrochloride (also called tetrahydrozoline) is a decongestant used in eye drops to relieve redness and minor irritation of the eyes caused by dust, smoke, wind, swimming pool water, tiredness or mild allergy. It is sometimes combined with an antihistamine or a lubricant. It is for short-term relief only and does not treat the cause.
How It Works
Tetryzoline stimulates alpha-adrenergic receptors in the small blood vessels on the surface of the eye, making them narrow. This quickly reduces redness and swelling, usually within minutes, and the effect lasts a few hours.
Dosage and Administration
Adults and children over 6 years (usually 0.05% drops): 1 to 2 drops into the affected eye(s) up to 2 to 4 times a day, or as directed on the label. Do not use for more than 3 days without medical advice. Wash your hands, tilt the head back, pull down the lower lid and put in the drop without touching the eye or eyelashes with the tip. Remove soft contact lenses first and wait at least 15 minutes before reinserting.
Interactions
- MAO inhibitors and tricyclic antidepressants: may increase effects on blood pressure if the drops are absorbed.
- Other eye drops: leave at least 5 minutes between different drops.
Contraindications
Do not use if you have narrow-angle glaucoma, are allergic to tetryzoline or any ingredient, or in children under 2 years. Not recommended for children 2 to 6 years unless a doctor advises it. Do not use for dry eye syndrome.
Side Effects
- Brief stinging, burning or irritation when the drops go in.
- Blurred vision or enlarged pupils for a short time.
- Rebound redness (eyes becoming redder) after frequent or long-term use.
- Rarely, headache, fast heartbeat, raised blood pressure or drowsiness if absorbed.
Get urgent medical help for severe eye pain, sudden change in vision, eye redness with headache and nausea (possible acute glaucoma), a very fast or irregular heartbeat, or swelling of the face and throat. If a child swallows the drops, seek emergency help at once.
Pregnancy and Lactation
There is limited information on use in pregnancy and breastfeeding. Use only if your doctor or pharmacist advises it, for the shortest time.
Precautions and Warnings
See a doctor if the redness lasts more than 3 days, if there is eye pain, discharge, sensitivity to light, change in vision, a foreign body or chemical in the eye, or if you have had recent eye surgery. Use with care if you have heart disease, high blood pressure, an overactive thyroid or diabetes. It may cause temporary blurred vision, so do not drive until it clears.
Overdose
Swallowing the drops is dangerous, especially for young children, and may cause drowsiness, slow breathing, low body temperature, slow heartbeat, coma or high then low blood pressure. Seek emergency medical help immediately.
Therapeutic Class
Ophthalmic decongestant (alpha-adrenergic agonist).
Storage
Store below 30°C, do not freeze, keep the bottle tightly closed, away from light and out of the reach of children. Discard 4 weeks after opening.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.