Drug information of Alphagan


Drug group:

Alphagan is a drug used to treat glaucoma. It acts via decreasing aqueous humor synthesis.

Mechanism of effect

Open-Angle Glaucoma or Ocular Hypertension

  • Alpha-2 adrenergic receptor agonist; decreases aqueous humor secretion, increases uveoscleral outflow

Ocular Redness

  • Dilutes alpha-2 receptor agonist; rapidly eliminates redness along the bulbar conjunctival microvasculature


Alphagan significantly lowers intraocular pressure with minimal effects on cardiovascular and pulmonary parameters. It lowers intraocular pressure by reducing aqueous humor production and increasing uveoscleral outflow.


Onset of action: 2hr (peak effect)

Half-Life: 2 hr

Peak plasma time: 0.5-2.5 hr

Metabolism: Liver

Excretion: urine (74%)

Drug indications

increased ocular tension



Elevated Intraocular Pressure

1 gtt in affected eye(s) q8hr

Ocular Redness

Instill 1 gtt in affected eye(s) q6-8hr


Elevated Intraocular Pressure

<2 years: Contraindicated

≥2 years: 1 gtt in affected eye(s) q8hr

Ocular Redness

<5 years: Safety and efficacy not established

≥5 years: Instill 1 gtt in affected eye(s) q6-8hr


Remove contact lenses before instilling eye drops; wait 15 min before reinserting contact lenses

If >1 ophthalmic product is being administered, wait 5 minutes between instilling eye drops

May potentiate syndromes associated with vascular insufficiency; caution with depression, cerebral or coronary insufficiency, Raynaud phenomenon, orthostatic hypotension, or thromboangiitis obliterans

Although Alphagan ophthalmic had minimal effect on the blood pressure of patients in clinical studies, caution with severe cardiovascular disease

Bacterial keratitis associated with the use of multiple-dose containers of topical ophthalmic products; instruct patients on how to avoid contamination

Drug interaction overview

  • Because Alphagan ophthalmic may reduce blood pressure, caution in using drugs such as antihypertensives and/or cardiac glycosides with advised
  • Although specific drug interaction studies have not been conducted with Alphagan ophthalmic, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics) should be considered
  • Tricyclic antidepressants (TCAs) have been reported to blunt the hypotensive effect of systemic clonidine; unknown whether the concurrent use TCAs with Alphagan ophthalmic can interfere with IOP lowering effect
  • MAOIs may theoretically interfere with the metabolism of Alphagan and potentially result in increased systemic effects (eg, hypotension); advise caution to patients taking MAO inhibitors

Points of recommendation

Use Alphagan exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Use only the number of drops your doctor has prescribed.

If you wear soft contact lenses, use the drops at least 10 minutes before inserting your lenses.

Wash your hands before using the eye drops.

To apply the Alphagan eye drops:

  • Tilt your head back slightly and pull down your lower eyelid to create a small pocket. Hold the dropper above the eye with the tip down. Look up and away from the dropper and squeeze out a drop.
  • Close your eyes for 1 to 2 minutes with your head tipped down, without blinking or squinting. Gently press your finger to the inside corner of the eye for about 1 minute, to keep the liquid from draining into your tear duct.
  • Use only the number of drops your doctor has prescribed. If you use more than one drop, wait about 5 minutes between drops.
  • Wait at least 5 minutes before using any other eye drops your doctor has prescribed.

Do not touch the tip of the eye dropper or place it directly on your eye. A contaminated dropper can infect your eye, which could lead to serious vision problems.

Do not use the Alphagan P eye drops if the liquid looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Store at room temperature away from moisture and heat. Do not freeze. Keep the bottle tightly closed when not in use.

Tell your doctor right away if you have any eye injury or infection, or if you need to have any type of surgery, especially eye surgery.

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