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Alphagan P Side Effects

Generic name: brimonidine ophthalmic

Medically reviewed by Last updated on May 14, 2023.

Note: This document contains side effect information about brimonidine ophthalmic. Some dosage forms listed on this page may not apply to the brand name Alphagan P.


Common side effects of Alphagan P include: blurred vision, burning sensation of eyes, drowsiness, eye pruritus, follicular conjunctivitis, headache, local ocular hypersensitivity reaction, ocular hyperemia, stinging of eyes, foreign body sensation, and xerostomia. Continue reading for a comprehensive list of adverse effects.

Applies to brimonidine ophthalmic: ophthalmic solution.

Serious side effects of Alphagan P

Along with its needed effects, brimonidine ophthalmic (the active ingredient contained in Alphagan P) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking brimonidine ophthalmic:

More common

  • Blurred or loss of vision
  • burning, dry, or itching eyes
  • discharge or excessive tearing
  • disturbed color perception
  • double vision
  • halos around lights
  • headache
  • itching of the eye
  • night blindness
  • overbright appearance of lights
  • redness of the eye or inner lining of the eyelid
  • swelling of the eyelid
  • tearing of the eye
  • tunnel vision

Less common

  • Ache or pain in the eye
  • blindness
  • bloody eye
  • blurred vision or other change in vision
  • change in color vision
  • confusion
  • decreased vision
  • difficult or labored breathing
  • difficulty seeing at night
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • drainage from the eye
  • fainting
  • fast heartbeat
  • feeling of something in the eye
  • gradual blurring or loss of vision
  • increased blood pressure
  • increased sensitivity of the eye to light
  • mental depression
  • muscle pain
  • nausea
  • oozing in the eye
  • redness, swelling, or itching of the eye or eyelid
  • runny or stuffy nose
  • seeing flashes or sparks of light
  • seeing floating dark spots or material before eyes
  • seeing floating spots before the eyes or a veil or curtain appearing across part of vision
  • skin rash
  • sneezing
  • sweating
  • swelling of the eye
  • tightness in the chest
  • unusual tiredness or weakness
  • vomiting
  • watery eyes

Incidence not known

  • Bluish lips or skin
  • chest pain or discomfort
  • confusion
  • fast, pounding, or irregular heartbeat or pulse
  • feeling of warmth or heat
  • flushing or redness of the skin, especially on the face and neck
  • irregular, fast, slow, or shallow breathing
  • low body temperature
  • muscle aches or weakness
  • shivering
  • slow or irregular heartbeat
  • weak or feeble pulse
  • weight gain

Other side effects of Alphagan P

Some side effects of brimonidine ophthalmic may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Burning, stinging, or tearing of the eye
  • drowsiness or tiredness
  • dryness of the mouth

Less common

  • Anxiety
  • bad, unusual, or unpleasant (after) taste
  • belching
  • body aches or pain
  • change in taste
  • chills
  • congestion
  • cough
  • cough producing mucus
  • crusting on the eyelid or on the corner of the eye
  • diarrhea
  • difficulty breathing
  • discoloration of the white part of the eye
  • dryness of the eye
  • dryness or soreness of the throat
  • fever
  • general feeling of discomfort or illness
  • hoarseness
  • indigestion
  • joint pain
  • lack or loss of strength
  • large amounts of cholesterol in the blood
  • lid disorder
  • loss of appetite
  • muscle aches and pains
  • pain or tenderness around the eyes and cheekbones
  • paleness of the eye or inner lining of the eyelid
  • passing of gas
  • pounding heartbeat
  • rash
  • shivering
  • sleepiness or unusual drowsiness
  • sneezing
  • sore throat
  • stomach discomfort, fullness, upset, or pain
  • tender, swollen glands in the neck
  • trouble with sleeping
  • trouble with swallowing
  • troubled breathing
  • unable to sleep
  • voice changes

Incidence not known

  • Constricted, pinpoint, or small pupils (black part of the eye)
  • redness of the skin
  • sensitivity to light
  • throbbing pain
  • unusual drowsiness, dullness, or feeling of sluggishness
  • unusual weak feeling
  • unusually warm skin

For Healthcare Professionals

Applies to brimonidine ophthalmic: ophthalmic solution, topical gel.


The most commonly reported side effects were oral dryness, ocular hyperemia, burning/stinging, headache, blurring, and foreign body sensation.[Ref]


Very common (10% or more): Ocular hyperemia (20%), burning/stinging (19%), foreign body sensation (12%), ocular pruritus, blurred vision (12%), allergic blepharitis, allergic blepharoconjunctivitis, allergic conjunctivitis, ocular allergic reaction, follicular conjunctivitis

Common (1% to 10%): Local irritation (eyelid hyperemia/edema, blepharitis, conjunctival edema/discharge, ocular pain /tearing), photophobia, corneal erosion/staining, ocular dryness, conjunctival blanching, abnormal vision, conjunctivitis, epiphora, superficial punctate keratitis, visual disturbance, worsening of visual acuity, cataract, vitreous detachment, vitreous disorder, vitreous floaters

Uncommon (0.1% to 1%): Conjunctival papilla, papillary hypertrophy, iritis, hordeolum

Very rare (less than 0.01%): Miosis

Frequency not reported: Lid crusting

Postmarketing reports: Iridocyclitis (anterior uveitis), eyelid pruritus, keratoconjunctivitis sicca[Ref]


Very common (10% or more): Oral dryness

Common (1% to 10%): Gastrointestinal symptoms[Ref]


Uncommon (0.1% to 1%): Palpitations/arrhythmias (including bradycardia and tachycardia)

Very rare (less than 0.01%): Hypertension, hypotension

Postmarketing reports: Pallor[Ref]

Nervous system

Very common (10% or more): Headache, drowsiness

Common (1% to 10%): Dizziness, abnormal taste

Uncommon (0.1% to 1%): Somnolence

Very rare (less than 0.01%): Syncope

Postmarketing reports: Coma, lethargy[Ref]


Common (1% to 10%): Upper respiratory symptoms, rhinitis, bronchitis, cough, flu syndrome

Uncommon (0.1% to 1%): Nasal dryness, pharyngitis

Rare (less than 0.1%): Dyspnea

Postmarketing reports: Respiratory depression[Ref]


Common (1% to 10%): Depression

Very rare (less than 0.01%): Insomnia

Frequency not reported: Anxiety[Ref]


Common (1% to 10%): Muscular pain[Ref]


Postmarketing reports: Skin reactions including erythema, pruritus, rash, vasodilatation[Ref]


Uncommon (0.1% to 1%): Systemic allergic reactions[Ref]


Common (1% to 10%): Hypercholesterolemia[Ref]


Very common (10% or more): Fatigue[Ref]

Frequently asked questions


1. "Product Information. Alphagan (brimonidine ophthalmic)." Allergan Inc (2001):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.