Generic name: Brimonidine.

Alphagan is an alpha-adrenergic receptor agonist. It stimulates aipha-2 receptors in the eye, which lower pressure by reducing the amount of liquid produced by the eye and increasing the rate of flow out of the eyeball. Peak effects occur 2 hours after dosage. 

Quick Facts About Alphagan


Used to treat glaucoma and ocular hypertension (high pressure inside the eye).

Alphagan Dosage

Take exactly as prescribed. Lie down or tilt head backward. Hold dropper above eye, look up, and drop medicine in lower lid. Release lower lid and wait 30 seconds before blinking. Do not allow dropper to touch eye; could cause infection. Press gently on bridge of nose near corner of afflicted eye for 1 minute to improve circulation of medication. Wait at least 5 minutes before applying other eye medication, and at least 15 minutes before inserting soft contact lenses.

  • Usual adult dose: 1 drop in the affected eye 3 times per day (every 8 hours).
  • Usual child dose: not generally prescribed for children.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Alphagan Side Effects

Overdose symptoms:

none reported. If you suspect an overdose, immediately seek medical attention.

More common side effects: abnormal vision, blurred vision, burning and stinging of eye, dizziness, drowsiness, dry eye or mouth, eye ache, allergy, irritation, itching, pain, eyelid redness or swelling, headache, muscle pain, redness, respiratory symp- i toms, sensation of something in eye, sensitivity to bright light, straining or erosion of cornea, upset stomach, weakness.

Less common Alphagan side effects: anxiety, crusting on eye-lid, dry nose, eye bleeding or discharge, fainting, heart palpitation, high blood pressure, sleeplessness, taste changes.


Inform your doctor before combining Alphagan with:

anesthetics; barbiturates such as phenobarbital; beta-blockers such as betaxolol or timolol; blood-pressure-lowering drugs; cardiac glycosides. Tricyclic antidepressants such as Elavil can increase the breakdown of Alphagan.

Do not combine alcohol with this medication; may increase effects of alcohol.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Small amount of medication may appear in bloodstream and breast milk; may affect a nursing infant.

No special precautions apply to seniors.

Not prescribed for children.

  • May cause drowsiness; use caution when driving or operating machinery.
  • Use with caution if you have: cardiovascular disease; cerebral or coronary insufficiency; depression; dizziness or fainting when rising from a sitting or lying position; kidney or liver disease.
  • Effects of Alphagan may diminish with time. Doctor should monitor eye pressure regularly and adjust dosage if necessary.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Alphagan side effects, please contact your healthcare provider.