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Alphagan: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Alphagan - General Information

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

 

Pharmacology of Alphagan

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.

 

Alphagan for patients

Brimonidine tartrate is used for the treatment of open-angle glaucoma and ocular hypertension. Do not take this drug if you are currently taking MAO Inhibitors (e.g., Parnate). Inform your doctor if you are pregnant or nursing.
This product may stain soft contact lenses. Wait at least 15 minutes after instilling brimonidine to insert contact lenses.
May cause drowsiness or tiredness; use caution while driving or operating hazardous machinery. May cause dry mouth, blurring, stinging, or burning of the eyes; headaches, fatigue or drowsiness; allergic or itching of the eyes. Tell your doctor or pharmacist if these effects occur.

 

Alphagan Interactions

Although specific drug interaction studies have not been conducted with ALPHAGAN P, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics) should be considered. Alpha-agonists, as a class, may reduce pulse and blood pressure. Caution in using concomitant drugs such as beta-blockers (ophthalmic and systemic), anti-hypertensives and/or cardiac glycosides is advised.

Tricyclic antidepressants have been reported to blunt the hypotensive effect of systemic clonidine.It is not known whether the concurrent use of these agents with ALPHAGAN P in humans can lead to resulting interference with the IOP lowering effect. No data on the level of circulating catecholamines after ALPHAGAN P administration are available. Caution, however, is advised in patients taking tricyclic antidepressants which can affect the metabolism and uptake of circulating amines.

 

Alphagan Contraindications

ALPHAGAN P is contraindicated in patients with hypersensitivity to brimonidine tartrate or any component of this medication. It is also contraindicated in patients receiving monoamine oxidase (MAO) inhibitor therapy.

 

Additional information about Alphagan

Alphagan Indication

For the lowering of intraocular pressure in patients with open-angle glaucoma or ocular hypertension.

Mechanism Of Action
Alphagan is an alpha adrenergic receptor agonist. It has a peak ocular hypotensive effect occurring at two hours post-dosing. Fluorophotometric studies in animals and humans suggest that Alphagan has a dual mechanism of action by reducing aqueous humor production and increasing uveoscleral outflow.
Generic Name
Brimonidine
Synonyms
Brimonidine tartrate; Bromoxidine
Drug Category
Antihypertensive Agents; EENT Drugs
Drug Type
Small Molecule; Approved
Other Brand Names containing Brimonidine
Alphagan; Alphagan P;
Absorption
Minimal systemic absorption occurs after ocular insertion.
Toxicity (Overdose)
Oral LD50 is 50 mg/kg in mice and 100 mg/kg in rats.
Biotransformation
Metabolized primarily by the liver.
Half Life
2 hours
Dosage Forms of Alphagan
Solution Ophthalmic
Chemical IUPAC Name
5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)quinoxalin-6-amine
Chemical Formula
C11H10BrN5
Organisms Affected
Humans and other mammals