bimatoprost

Action and Spectrum

Actions and Spectrum:  

bimatoprost acts primarily on the trabecular meshwork, a network of tissue located near the base of the cornea, which plays a key role in regulating the drainage of aqueous humor from the eye.

By enhancing the outflow of aqueous humor through the trabecular meshwork and possibly other pathways, bimatoprost helps to lower IOP and alleviate the risk of optic nerve damage associated with glaucoma. 

The spectrum of activity of bimatoprost is primarily limited to its effects on the eye, specifically in reducing IOP and enhancing eyelash growth.

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Adults: 

Growth of eyelashes (15-45%) 

Ocular pruritus (15-45%) 

Conjunctival hyperemia (25-45%) 

Adults 

1-10% 

Asthenopia (1-3%) 

Increases in iris pigmentation (1-3%) 

Superficial punctate keratitis (3-10%) 

Conjunctival edema (1-3%) 

Eyelid erythema (3-10%) 

Visual disturbance (3-10%) 

Ocular irritation (3-10%) 

Ocular burning (3-10%) 

Foreign body sensation (3-10%) 

Ocular pain (3-10%) 

Ocular irritation (3-10%) 

Conjunctival edema (1-3%)  

Frequency not defined  

Iris hyperpigmentation 

Lacrimation increased. 

Madarosis and trichorrhexis 

Skin discoloration (periorbital) 

Blurred vision 

Black Box Warning

Black Box Warning:  

WARNING: IRIS PIGMENT CHANGES AND EYELID SKIN DARKENING 

bimatoprost, a prostaglandin analog, is indicated for the treating elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension. However, treatment with bimatoprost has been associated with the following serious adverse effects:  

Iris Pigment Changes: bimatoprost may cause increased pigmentation of the iris, resulting in permanent changes to the color of the eye. These changes may be noticed as increased brown pigmentation of the iris, which may be more pronounced in patients with mixed-color irides.   

Eyelid Skin Darkening: bimatoprost may cause increased pigmentation of the skin of the eyelids. This can result in darkening of the skin of the eyelids, which may be reversible upon discontinuation of the medication. 

Contraindication / Caution

Contraindication/Caution:   

Hypersensitivity: bimatoprost is contraindicated in patients with known hypersensitivity or allergy to bimatoprost or any of the components of the formulation. Hypersensitivity reactions, including severe allergic reactions, have been reported using bimatoprost and may manifest as swelling, redness, itching, or rash.  

Pregnancy and Lactation: bimatoprost is contraindicated in pregnant and lactating women. Animal studies have shown adverse effects on fetal development, including teratogenicity and embryotoxicity, with systemic exposure to bimatoprost.  

Ophthalmic Conditions: bimatoprost is contraindicated in patients with certain ophthalmic conditions, including active intraocular inflammation (e.g., iritis, uveitis), neovascular glaucoma, and angle-closure glaucoma.  

Children: bimatoprost is contraindicated in children below the age of 16 years, as safety and efficacy have not been established in this population.  

Contact Lens Use: bimatoprost is contraindicated in patients wearing contact lenses, as soft contact lenses may absorb the preservatives in the formulation and may cause eye irritation or discoloration of the lenses. 

Pregnancy / Lactation

Pregnancy warnings:     

Pregnancy category: N/A 

Lactation: Excreted into human milk is unknown 

Pregnancy Categories:         

Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester. 

Category B: There were a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.   

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.   

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology: 

It is a selective agonist for the prostaglandin FP receptor. It is primarily used as a medication to lower intraocular pressure (IOP) in glaucoma and ocular hypertension. 

Pharmacodynamics: 

bimatoprost exerts its pharmacodynamic effects through selective activation of the prostaglandin FP receptor. Upon binding to the FP receptor, bimatoprost triggers a series of intracellular events that ultimately lead to modulation of intraocular pressure (IOP) and reduction of IOP in glaucoma and ocular hypertension. 

MOA: 

bimatoprost lowers IOP by increasing the outflow of aqueous humor, the fluid inside the eye, through trabecular meshwork and uveoscleral routes. This results in reduced resistance to the outflow of aqueous humor, leading to a decrease in IOP.  

Pharmacokinetics:  

Absorption 

When applied to the eye, bimatoprost is readily absorbed through the cornea and conjunctiva into the eye’s anterior chamber . The absorption of bimatoprost is rapid, with peak plasma concentrations achieved within 10 minutes to 1 hour after ocular administration. 

Distribution 

The drug is primarily distributed to ocular tissues, including the uvea, iris, and ciliary body, where it exerts its pharmacological effects 

Metabolism 

bimatoprost undergoes metabolism primarily in the liver via oxidation, hydrolysis, and conjugation. The major metabolic pathway involves oxidation of the isopropyl ester moiety of bimatoprost to form the biologically active acid metabolite, which is responsible for the pharmacological effects of the drug. 

Excretion and Elimination 

bimatoprost and its metabolites are primarily excreted in the urine and feces. The elimination half-life of bimatoprost is estimated to be approximately 45 minutes to 1.5 hours, indicating rapid clearance from the systemic circulation. Most of the drug is eliminated as metabolites in the urine, with only a tiny portion excreted unchanged. 

Adminstartion

Administration:  

bimatoprost is intended for ophthalmic use only and should be administered according to the following instructions: 

Hand Hygiene: Wash hands thoroughly while using.  

Eye Preparation: If wearing contact lenses, remove them before applying bimatoprost. Wait at least 15 minutes after administration before reinserting contact lenses. 

Cleanse the eyelids and lashes of any debris or makeup using a mild cleanser or sterile saline solution.  

Dosage and Frequency: The recommended dosage of bimatoprost is one drop in the affected eye(s) once daily in the evening. The concentration and frequency of bimatoprost may vary depending on the formulation and indication and should be prescribed and adjusted by a qualified healthcare professional. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: bimatoprost 

Why do we use bimatoprost ?  

Glaucoma: bimatoprost is indicated for the treatment of all the severe form of glaucoma. 

Ocular Hypertension: bimatoprost is indicated for the management of ocular hypertension, which is characterized by elevated intraocular pressure without optic nerve damage or visual field loss.

ocular hypertension is considered a significant risk factor for the development of glaucoma, and lowering intraocular pressure with medications like bimatoprost can help prevent or delay the onset of glaucoma.