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 accomm ...

), also known under the brand name Iopidine, is a sympathomimetic used in

glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

therapy. It is an α₂ adrenergic receptor

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

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. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated t ...

(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 surgery or ocular surgery, is surgery performed on the eye or its adnexa. Eye surgery is part of ophthalmology and is performed by an ophthalmologist or eye surgeon. The eye is a fragile organ, and require ...

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 cond ...

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 α2A-adrenergic receptor agonist medication used to treat high blood pressure, attention deficit hyperactivity disorder (ADHD), drug withdrawal (e.g., alcohol, opioids, or nic ...

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

pilocarpine Pilocarpine, sold under the brand name Pilopine HS among others, is a lactone alkaloid originally extracted from plants of the Pilocarpus genus. It is used as a medication to reduce pressure inside the eye and treat dry mouth. As an eye drop ...

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 Imidazoline receptor modulators Imidazolines Ophthalmology drugs Sympathomimetic amines

Clinical uses

References

Further reading

External links