Brimonidine eye drops (Alphagan P and others)

How Medicare covers it

Part D (eye drops and skin gel used at home taken/used at home). Part A during a covered inpatient stay. No Part B clinician-administered form in the CMS Part B spending file.

What it treats

Lowers raised pressure inside the eye (elevated intraocular pressure, or IOP) in people with open-angle glaucoma or ocular hypertension (high eye pressure without glaucoma damage yet). This entry is based on the eye-drop label.

What it is for, in depth

Brimonidine eye drops are a daily treatment for raised pressure inside the eye, prescribed for people with open-angle glaucoma — the common form of glaucoma, in which high pressure can slowly damage the optic nerve and vision — and for ocular hypertension, where pressure is high but damage has not yet occurred. Lowering pressure is the goal of treatment, and brimonidine is one of the eye-drop options used every day to do that; the label allows it to be used together with other pressure-lowering eye products when one drop alone is not enough. It controls pressure but does not cure glaucoma, so it is used on an ongoing schedule, three times a day. This label covers ophthalmic solution in 0.1% (1 mg/mL) and 0.15% (1.5 mg/mL) strengths, in 5 mL, 10 mL, and 15 mL bottles.

How it works

Brimonidine is a relatively selective alpha-2 adrenergic agonist for the eye. It lowers eye pressure in two ways: it reduces the amount of fluid (aqueous humor) the eye makes, and it increases fluid drainage out of the eye through the uveoscleral pathway. Its peak pressure-lowering effect occurs about 2 hours after a dose.

How it is taken

Eye drops: one drop of the 0.1% or 0.15% solution in the affected eye or eyes three times a day, about 8 hours apart. It may be used together with other eye-drop products that lower eye pressure; if you use more than one eye product, put them in at least 5 minutes apart. Do not touch the dropper tip to your eye or anything else, to keep the bottle clean.

Common side effects

The most common side effects, reported in about 5% to 20% of patients using brimonidine eye solution (0.1% to 0.2%), were allergic conjunctivitis (an eye allergy reaction), a burning feeling, conjunctival folliculosis (small bumps on the inner eyelid surface), eye redness, eye itching, raised blood pressure, eye allergic reaction, dry mouth, and disturbed vision. Allergic conjunctivitis, eye redness, and eye itching were the most frequent, at about 10% to 20%.

Serious warnings

Brimonidine may make conditions linked to poor blood circulation (vascular insufficiency) worse, and it should be used with caution in severe heart or blood-vessel disease even though it had little effect on blood pressure in studies. Using a contaminated eye-drop bottle can cause a serious bacterial eye infection (keratitis) and loss of vision. Effects reported after marketing include slow heart rate, fainting, depression, and eye inflammation.

Who should be careful

Do not use it in babies and infants younger than 2 years old — serious effects including slowed breathing, coma, low body temperature, and extreme sleepiness have been reported in infants — and do not use it if you have had an allergic reaction to any part of the product. Use with caution if you have depression, poor circulation to the brain or heart, Raynaud's phenomenon, low blood pressure on standing, or thromboangiitis obliterans, or severe cardiovascular disease.

Major interactions

Blood-pressure medicines and cardiac glycosides may add to a blood-pressure-lowering effect, so caution is advised. Sedating central nervous system depressants — alcohol, barbiturates, opioids, sedatives, or anesthetics — may have an added effect. Tricyclic antidepressants can affect how the body handles this type of drug and need caution, and monoamine oxidase (MAO) inhibitors may add to the risk of low blood pressure.

Cost and saving notes

Brimonidine eye drops are generic, so many people pay a low Tier 1 copay. If your plan charges more than you can afford, you or your prescriber can ask the Part D plan for a tiering exception to move a covered drug to a lower cost-sharing tier when your prescriber supports it. Extra Help, the Part D Low-Income Subsidy, lowers premiums, deductibles, and copays for people with limited income and resources. In 2027, what you pay out of pocket for covered Part D drugs is capped at $2,400 for the year, and after you reach that cap you pay $0 for covered Part D drugs for the rest of the year. The Medicare Prescription Payment Plan is a separate option that spreads your covered drug costs into monthly payments over the rest of the plan year instead of paying large amounts at the pharmacy counter.

Why it is in its tier

Brimonidine is most often placed on Tier 1 in 2027 Part D formularies — the modal tier for about 69% of listing plans — and every plan in the data (100%) lists it. Tier 1 is the preferred generic tier in most plans, with the lowest copays. That fits the data: the generic brimonidine tartrate row in the CMS Part D dashboard averaged $147.88 per beneficiary for 2024, while the brand Alphagan P row under the same generic name averaged $1,336.67 per beneficiary — a clear generic-versus-brand cost gap. Those dashboard figures are program averages, not your copay. The tier shown is the most common one, and individual plans vary, so check your own plan's drug list.

Sources

• BRIMONIDINE TARTRATE SOLUTION/ DROPS [PACIFIC PHARMA, INC.] — DailyMed
• MedlinePlus — National Library of Medicine
• MedlinePlus — Brimonidine Ophthalmic

What official patient guides say

Brimonidine ophthalmic comes as a solution (liquid) to instill in the eyes, usually in the affected eye or eyes 3 times a day. Use the drops at around the same times every day and try to space the 3 daily doses about 8 hours apart, continuing even if you feel well and not stopping without talking to your doctor. To use them, wash your hands, keep the dropper tip clean and do not touch it to your eye or anything else, and if you need more than one drop in the same eye wait at least 5 minutes before the next drop. If you forget a dose, instill it as soon as you remember unless it is almost time for the next dose, in which case skip it and do not instill a double dose. Keep it in its tightly closed container at room temperature, away from excess heat and moisture, and out of reach of children.

Source: MedlinePlus — Brimonidine Ophthalmic

Part D formulary coverage

Source: CMS Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files — Monthly file 2026-10-15 (plan year 2027), file 2027_20261008.zip (data.cms.gov dataset ed1496ea-23e7-41f1-9292-172fa842ccfb): basic drugs formulary file + plan information file, both dated 20261031 inside the zip; downloaded and aggregated 2026-10-30. Medication RxCUI sets resolved through the NLM RxNav (RxNorm) API.

What you pay

Without insurance, the cash benchmark is 37.34018 per unit (ALPHAGAN P 0.1% DROPS) — about nan for 30 units. NADAC benchmark — the average price pharmacies pay (CMS, as of 2026-11-04). Pharmacy shelf prices vary.

A tier is not a price; what you pay depends on your plan, pharmacy, and benefit stage; Extra Help or Medicaid can lower it further.

Sources: CMS Plan Benefit Package + formulary data; CMS NADAC · Checked 2026-11-07

Coverage by plan and tier

Of the 5,495 Medicare drug plans we track for 2027, 5,495 list Brimonidine eye drops (Alphagan P and others) — 100% of plans. Most of those plans put it on Tier 1: 3,797 plans, 69.1% of the plans that list it. Other plans place it on Tier 2 (915 plans), Tier 3 (597 plans) or Tier 4 (186 plans). For example: Aetna Medicare Dual Extra (HMO D-SNP) puts it on Tier 1; Aetna Medicare Dual Extra Care (PPO D-SNP) puts it on Tier 1; Aetna Medicare Value Plus (PPO) puts it on Tier 1. You can compare these plans side by side on our Medicare Advantage hub. A tier is not a price. What you pay also depends on whether you have met your plan';s deductible, whether the drug costs a flat copay or a share of the price, and whether you get Extra Help or Medicaid.

Read next

• Part D in 2027: The $700 Deductible, the $2,400 Cap, and the $35 Insulin Rule
• Extra Help in 2027: Lower Drug Copays and Who Qualifies
• Checking Medicare Savings Programs and Extra Help

Part D spending averages (2024)

Source: CMS Medicare Part D Spending by Drug (Drug Spending Dashboard), release RY26 P04 V10, data through 2024 (DSD_PTD_RY26_P04_V10_DY24_BGM.csv), downloaded 2026-10-30

Companies covering this drug

Part D and Medicare Advantage plan sponsors that list this drug on a formulary, 50 at a time.