For prevention or reduction of intraoperative and postoperative increases in intraocular pressure (IOP) before and after ocular laser surgery when used prophylactically. Also used as a short-term adjunctive therapy in patients with open-angle glaucoma who are on maximally tolerated medical therapy requiring additional IOP reduction.
Apraclonidine is a relatively selective alpha2 adrenergic receptor agonist that stimulates alpha1 receptors to a lesser extent. It has a peak ocular hypotensive effect occurring at two hours post-dosing. The exact mechanism of action is unknown, but fluorophotometric studies in animals and humans suggest that Apraclonidine has a dual mechanism of action by reducing aqueous humor production through the constriction of afferent ciliary process vessels, and increasing uveoscleral outflow.
Accidental or intentional ingestion of oral apraclonidine has been reported to cause apnea, arrhythmias, asthenia, bradycardia, conduction defects, diminished or absent reflexes, dryness of the mouth, hypotension, hypothermia, hypoventilation, irritability, lethargy, miosis, pallor, respiratory depression, sedation or coma, seizure, somnolence, transient hypertension, and vomiting.
Topical use of apraclonidine ophthalmic solution leads to systemic absorption. Studies of apraclonidine (0.5% ophthalmic solution) dosed one drop three times a day in both eyes for 10 days in normal volunteers yielded mean peak and trough concentrations of 0.9 ng/mL and 0.5 ng/mL, respectively.
8 hours
May be used as an adjunct in the treatment of hypertension, as an epidural infusion as an adjunct treatment in the management of severe cancer pain that is not relieved by opiate analgesics alone, for differential diagnosis of pheochromocytoma in hypertensive patients, prophylaxis of vascular migraine headaches, treatment of severe dysmenorrhea, management of vasomotor symptoms associated with menopause, rapid detoxification in the management of opiate withdrawal, treatment of alcohol withdrawal used in conjunction with benzodiazepines, management of nicotine dependence, topical use to reduce intraocular pressure in the treatment of open-angle and secondary glaucoma and hemorrhagic glaucoma associated with hypertension, and in the treatment of attention-deficit hyperactivity disorder (ADHD).
See Pharmacology section above.
Oral LD<sub>50</sub> is 150 mg/kg in rat and 30 mg/kg in dog. Symptoms of overdose include constriction of pupils of the eye, drowsiness, high blood pressure followed by a drop in pressure, irritability, low body temperature, slowed breathing, slowed heartbeat, slowed reflexes, and weakness.
Well absorbed following oral administration. Bioavailability following chronic administration is approximately 65%.
6-20 hours; 40-60% is excreted in urine unchanged, 20% is excreted in feces. Less than 10% is excreted by <i>p</i>-hydroxyclonidine.