Bimatoprost

How it works

It increases aqueous humour outflow, predominantly through the uveoscleral pathway, thereby reducing intraocular pressure.

Prescribing in practice

• Warn patients that it can cause permanent darkening of the iris and eyelid skin and increased growth and pigmentation of eyelashes, with iris colour change being irreversible.
• It can cause conjunctival hyperaemia and may reactivate or worsen ocular inflammation, so use with caution in active uveitis or a history of macular oedema.
• Wipe away any excess to reduce darkening of periocular skin.

Monitoring

Monitor intraocular pressure for response and observe for iris and periocular pigmentation changes, eyelash changes and conjunctival hyperaemia.

Counselling the patient

• Be aware that eye colour, eyelid skin and eyelash appearance can change, and iris colour change may be permanent.
• If treating one eye, this can cause a difference in appearance between the eyes.
• Remove contact lenses before instillation and wait before reinserting.

Evidence & guidelines

Bimatoprost is an established first-line prostaglandin analogue for open-angle glaucoma and ocular hypertension, with NICE recommending this class as initial therapy.