Latanoprost is a prescription medication delivered through eye drops, designed to manage conditions characterized by elevated pressure inside the eye. As a member of the prostaglandin analog class of drugs, it works locally within the eye to help regulate the pressure of the internal fluid. It is typically administered as a single daily drop to provide a sustained reduction in intraocular pressure.
Therapeutic Conditions Latanoprost Addresses
The primary purpose of latanoprost is to reduce elevated intraocular pressure (IOP) in patients diagnosed with two specific conditions. These conditions are open-angle glaucoma and ocular hypertension. Ocular hypertension describes a state where the pressure within the eye is higher than considered normal, but without observable damage to the optic nerve.
Open-angle glaucoma is a more advanced disease where the elevated pressure has already begun to cause progressive damage to the optic nerve. This nerve damage can lead to irreversible loss of peripheral vision and, if left untreated, eventual blindness. By consistently lowering IOP, latanoprost helps to reduce the mechanical stress on the optic nerve fibers.
The goal of treatment is to prevent further deterioration of the optic nerve and preserve the patient’s remaining visual field. Because elevated IOP is a major risk factor for vision loss, controlling it is a continuous and long-term necessity. Therefore, this medication is intended to control the condition rather than provide a cure.
How Latanoprost Reduces Intraocular Pressure
Latanoprost is initially absorbed into the cornea as an inactive chemical compound known as an isopropyl ester prodrug. Once inside the eye’s tissues, specific enzymes hydrolyze it, converting it into the biologically active latanoprost acid. This active form then acts as a selective agonist, meaning it binds to and stimulates specific receptors known as prostaglandin FP receptors.
Stimulation of these receptors initiates a cascade of molecular events in the eye’s internal structures. The primary result is an increase in the outflow of aqueous humor, the clear fluid that fills the space between the lens and the cornea. This fluid drains mainly through the uveoscleral outflow pathway, which is distinct from the conventional drainage route.
The drug increases the permeability of the uveoscleral tissues by triggering the remodeling of the extracellular matrix. This restructuring creates wider spaces, allowing the aqueous humor to pass through the tissues more easily and exit the eye. Pressure reduction typically begins within three to four hours after application, reaching its maximum effect approximately eight to twelve hours later, and the reduction is maintained for a full 24-hour period.
Correct Administration and Handling of Eye Drops
Proper application and handling of latanoprost drops are important for ensuring effectiveness and preventing potential infection. Before beginning the process, the patient must wash their hands thoroughly with soap and water. The medicine is typically dosed as one drop in the affected eye or eyes once daily, usually in the evening, as this aligns with the natural circadian rhythm of intraocular pressure.
To apply the drop, the patient should tilt their head backward and gently pull down the lower eyelid to create a small pocket. The dropper tip must be held directly over the eye without touching the eye, eyelid, or any other surface to avoid contamination. After the drop is released into the pocket, the patient should close their eye and immediately press a finger gently over the inner corner of the eyelid near the nose for about one minute. This step, known as punctal occlusion, minimizes the amount of medication that drains into the nasal passages, reducing the risk of systemic absorption and enhancing the local effect.
If a patient uses other topical eye medications, they should wait at least five minutes between applications to prevent the wash-out of the latanoprost. Unopened bottles of latanoprost must be stored in a refrigerator to maintain the drug’s stability. Once a bottle is opened, it can generally be kept at room temperature, but it must be discarded after four to six weeks, even if there is medication remaining.
Managing Common and Distinct Adverse Reactions
Patients using latanoprost may experience common side effects that are confined to the eye. These reactions include stinging, burning, or irritation following application. Some individuals may notice temporary redness of the conjunctiva. Dry eye and temporary blurred vision are also occasionally reported.
More distinct and long-term adverse reactions are associated with the drug’s classification as a prostaglandin analog, and patients should be aware of these potential cosmetic changes. The most notable effect is the potential for a gradual, permanent change in iris color, typically resulting in an increase in brown pigmentation. This change is more frequently observed in individuals with mixed-color irises, such as blue-brown or hazel eyes.
Latanoprost also commonly causes changes to the eyelashes of the treated eye. These changes include increased length, thickness, and number of lashes, along with a potential darkening of their color. Patients should consult their eye care specialist if they notice these changes, especially if the medication is being used in only one eye, as this can lead to a noticeable difference in color between the two eyes.