Bimatoprost

Bimatoprost is available in several products approved for different uses — not every form treats every condition.

• Lumigan (eye drops): reduces elevated intraocular pressure in open-angle glaucoma or ocular hypertension
• Zolymbus (eye ointment): reduces elevated intraocular pressure in open-angle glaucoma or ocular hypertension
• Durysta (intracameral implant): reduces intraocular pressure in open-angle glaucoma or ocular hypertension — given as a one-time implant inside the eye by a clinician
• Latisse (eye drops applied topically): treats hypotrichosis of the eyelashes — sparse, thin, or short lashes — by increasing their length, thickness, and darkness
• Bimatoprost ophthalmic solution 0.03%: also approved to treat hypotrichosis of the eyelashes

Bimatoprost is a synthetic prostaglandin analog — meaning it's built to mimic natural substances in the body called prostamides. For glaucoma and high eye pressure, it works by opening up the eye's drainage channels (called the trabecular meshwork and uveoscleral routes), letting excess fluid called aqueous humor drain out more easily. Less fluid inside the eye means lower pressure, which protects the optic nerve from damage and helps preserve vision.

The right way to take bimatoprost depends on which product your doctor prescribes — do not mix up instructions between products.

• Lumigan eye drops: one drop in the affected eye(s) once each evening — never more than once daily
• Zolymbus eye ointment: one drop from a single-dose container in the affected eye(s) once each evening; open and use immediately, then discard the container
• Latisse / bimatoprost 0.03% for lashes: applied once nightly to the upper eyelid skin at the lash base using a sterile applicator; use a fresh applicator for each eye and discard after use
• Durysta implant: a one-time procedure performed by a healthcare provider; the implant should not be repeated in the same eye

If you miss a dose of an eye drop or ointment, just continue with your next scheduled dose — don't double up. Always follow your prescriber's specific directions.

The most common side effects affect the eyes and are often mild, but some changes can be permanent.

• Eye redness (the most common side effect, seen in up to 45% of users)
• Increased eyelash growth or darkening
• Eye itching
• Eye dryness, burning, or foreign body sensation
• Darkening of the skin around the eye or eyelids (usually reversible when stopped)
• Darkening or color change of the iris — this may be permanent
• Eye pain or visual disturbance
• Colds or upper respiratory infections (about 10% of users)

Seek medical attention if you notice sudden vision changes, signs of eye inflammation (pain, redness, light sensitivity), swelling around the eye, or signs of an allergic reaction such as severe redness or skin rash.

• Permanent iris color change: Bimatoprost can cause the iris to become more brown over time. This can affect one or both eyes and may take months to years to appear. It is likely irreversible — meaning it stays even after you stop the medication. If you use it in only one eye, that eye may permanently end up a different color than the other.
• Eyelid and skin darkening: The skin around the eye and the eyelashes can darken with use. Unlike iris changes, this darkening of the eyelid skin is usually reversible when treatment stops.
• Unwanted hair growth: If the solution regularly contacts skin outside the upper eyelid (like the cheek), hair may grow in those areas. Careful application and blotting of any excess is important.
• Eye inflammation: Use with caution if you have active uveitis (inflammation inside the eye) — bimatoprost may worsen it.
• Macular edema: Swelling at the center of the retina has been reported, especially in people who've had certain eye surgeries or have risk factors. Tell your doctor your full eye history.
• Interaction with other prostaglandin eye drops: Using bimatoprost alongside another prostaglandin analog can reduce the eye pressure-lowering effect of both.

Bimatoprost has a few important interactions to be aware of, mostly involving other eye medications.

• Other prostaglandin analog eye drops (e.g., Lumigan, Travatan, Xalatan): Using bimatoprost alongside another drug in this class can reduce how well either one lowers eye pressure — your doctor needs to know about all eye drops you use.
• Other topical eye drops in general: If you use more than one eye drop, wait at least 5 minutes between each to avoid washing one out before it works.
• Soft contact lenses: Some bimatoprost eye drop products contain benzalkonium chloride, a preservative that can be absorbed by soft contact lenses and cause discoloration. Remove lenses before applying drops and wait 15 minutes before putting them back in.

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Allergy: Do not use bimatoprost if you are allergic to it or to any ingredient in the product.
• Eye inflammation: Tell your doctor if you have uveitis or other active eye inflammation — bimatoprost may make it worse.
• Recent eye surgery or lens issues: If you've had lens surgery (aphakia or pseudophakia with a torn capsule) or are at risk for macular edema, discuss this with your doctor first.
• Pregnancy: There are no adequate studies in pregnant people. Animal studies at high doses showed risks, but those doses were far higher than typical eye drop exposure. Use only if your prescriber decides the benefit justifies the risk.
• Breastfeeding: It's not known whether bimatoprost passes into human breast milk in significant amounts. Discuss with your doctor.
• Children: Bimatoprost ophthalmic solution 0.03% has been studied for eyelash growth in children ages 5–17 in certain conditions; discuss pediatric use with a prescriber.
• Older adults: No significant differences in safety or effectiveness have been seen between older and younger adults.

There is no information on what happens if a person takes too much bimatoprost. If an overdose occurs, treatment is focused on managing whatever symptoms appear — there is no specific antidote. In animal studies, very high oral doses did not cause toxicity, and the amount in one bottle is well below concerning levels even for a child. If you're worried about accidental exposure, contact Poison Control or seek medical advice.

Bimatoprost lowers intraocular pressure by increasing how much fluid drains out of the eye through two routes: the trabecular meshwork and the uveoscleral pathway. For eye drop products, pressure reduction begins about 4 hours after the first dose, with the maximum effect reached within 8 to 12 hours. Using more than one dose per day does not increase the benefit — in fact, it may actually reduce the pressure-lowering effect, which is why once-daily dosing is recommended.

When bimatoprost eye drops are applied to the eye, a small amount is absorbed into the bloodstream. Blood levels peak within about 10 minutes of dosing and fall below detectable levels within 1.5 hours in most people — meaning very little drug accumulates in the body over time. Once in the bloodstream, bimatoprost is broken down (metabolized) by the liver through oxidation and other processes. About 67% of the drug is eventually cleared through the urine and 25% through the feces. The elimination half-life (the time it takes for half the drug to leave the blood) is approximately 45 minutes.

Store at 2°C to 25°C (36°F to 77°F).