Apraclonidine (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

), also known under the brand name Iopidine, is a

sympathomimetic Sympathomimetic drugs (also known as adrenergic drugs and adrenergic amines) are stimulant compounds which mimic the effects of endogenous agonists of the sympathetic nervous system. Examples of sympathomimetic effects include increases in heart ...

used in

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye re ...

therapy. It is an α₂ adrenergic receptor

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

and a weak α₁ adrenergic receptor agonist. Topical apraclonidine is administered at a concentration of 1% for the prevention and treatment of post-surgical

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response fu ...

(IOP) elevation and 0.5% for short-term adjunctive therapy in patients on maximally tolerated medical therapy who require additional reduction of IOP. One drop is usually added one hour prior to laser

eye surgery Eye surgery, also known as ophthalmic or ocular surgery, is surgery performed on the eye or its adnexa, by an ophthalmologist or sometimes, an optometrist. Eye surgery is synonymous with ophthalmology. The eye is a very fragile organ, and requ ...

and another drop is given after the procedure is complete.

Clinical uses

Apraclonidine is indicated for the short-term adjunctive treatment of glaucoma for patients on maximally tolerated medical therapy who require additional reduction of IOP. These patients, who are treated with apraclonidine to delay surgery, should have frequent follow-up examinations and treatment should be discontinued if the intraocular pressure rises significantly. Apraclonidine may be useful in the diagnosis of

Horner's syndrome Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...

. In Horner's syndrome, the sympathetic innervation to the pupillary dilator muscle is lost. The affected pupil is thus miotic and the pupillary dilator responds to denervation by increasing α₁ receptors. Apraclonidine is useful in this case due to its weak α₁-adrenergic properties. When applied to the denervated (and thus hyper-sensitive) pupillary dilator muscle, a super-normal dilatory response is generated in which the pupil dilates to a degree greater than that which would be seen in a non-denervated muscle. This causes the reversal of

anisocoria Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting up to 20% of the population, anisocoria is often entirely harmless, but can be a sign of more serious medical problems. Causes Anisocoria is a common condit ...

that is characteristic of Horner's. Topical apraclonidine can also decrease IOP in glaucoma patients by increasing trabecular outflow, in a similar way to

clonidine Clonidine, sold under the brand name Catapres among others, is an α2-adrenergic agonist medication used to treat high blood pressure, ADHD, drug withdrawal ( alcohol, opioids, or nicotine), menopausal flushing, diarrhea, spasticity, an ...

, but without the cardiovascular side effects. Apraclonidine has been compared with other treatments such as

brimonidine Brimonidine is a medication used to treat open-angle glaucoma, ocular hypertension, and rosacea. In rosacea it improves the redness. It is used as eye drops or applied to the skin. Common side effects when used in the eyes include itchiness, ...

and

pilocarpine Pilocarpine is a medication used to reduce pressure inside the eye and treat dry mouth. As eye drops it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to bring ab ...

in preventing IOP spikes after laser trabeculoplasty. The results did not show significant differences in the reduction of IOP for apraclonidine, when compared to brimonidine or pilocarpine.

References

External links

Iopidine prescribing information
(from the FDA website) {{Imidazoline receptor modulators Alpha-1 adrenergic receptor agonists Alpha-2 adrenergic receptor agonists Chloroarenes Guanidines Imidazolines Sympathomimetic amines Ophthalmology drugs

Clinical uses

References

Further reading

External links