2871 Clonidine Clonidine, an imidazoline-derivative hypotensive agent is a centrally-acting &alpha;₂-adrenergic agonist. It crosses the blood-brain barrier and acts in the hypothalamus to induce a decrease in blood pressure. It may also be administered as an epidural infusion as an adjunct treatment in the management of severe cancer pain that is not relieved by opiate analgesics alone. Clonidine may be used for differential diagnosis of pheochromocytoma in hypertensive patients. Other uses for clonidine include 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). Clonidine also exhibits some peripheral activity. 4205-90-7 2803 C9H9Cl2N3 229.017350 White powder. 305°C Appreciable Well absorbed following oral administration. Bioavailability following chronic administration is approximately 65%. Clonidine acts as an agonist at presynaptic alpha(2)-receptors in the nucleus tractus solitarius of the medulla oblongata. Stimulation of these receptors results in the supression of efferent sympathetic pathways and the subsequent decrease in blood pressure and vascular tone in the heart, kidneys, and peripheral vasculature. Clonidine is also a partial agonist at presynaptic alpha(2)-adrenergic receptors of peripheral nerves in vascular smooth muscle. Hepatic. Metabolized via minor pathways. The major metabolite, <i>p</i>-hydroxyclonidine, is present in concentrations less than 10% of those of unchanged clonidine in urine. Four metabolites have been detected, but only <i>p</i>-hydroxyclonidine has been identified. Half Life: 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. LD50: 150 mg/kg (oral, rat) LD50: 30 mg/kg (oral, dog) No indication of carcinogenicity to humans (not listed by IARC). 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). 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. There is no specific antidote for clonidine overdosage. Clonidine overdosage may result in the rapid development of CNS depression; therefore, induction of vomiting with ipecac syrup is not recommended. Gastric lavage may be indicated following recent and/or large ingestions. Administration of activated charcoal and/or a cathartic may be beneficial. Supportive care may include atropine sulfate for bradycardia, intravenous fluids and/or vasopressor agents for hypotension and vasodilators for hypertension. Naloxone may be a useful adjunct for the management of clonidine-induced respiratory depression, hypotension and/or coma; blood pressure should be monitored since the administration of naloxone has occasionally resulted in paradoxical hypertension. Tolazoline administration has yielded inconsistent results and is not recommended as first-line therapy. (L1712) 2009-07-21T20:27:11Z 2014-12-24T20:25:52Z Clonidine C07668 46631 Clonidine DB00575 CLU true ClC1=CC=CC(Cl)=C1NC1=NCCN1 C9H9Cl2N3 InChI=1S/C9H9Cl2N3/c10-6-2-1-3-7(11)8(6)14-9-12-4-5-13-9/h1-3H,4-5H2,(H2,12,13,14) InChIKey=GJSURZIOUXUGAL-UHFFFAOYSA-N 230.094 229.017352717 Exogenous Solid 1.59 HMDB14714 CHEMBL134 2701 <p>David R. Pierce, William D. Dean, Michael E. Deason, &#8220;Process for preparation of clonidine derivatives.&#8221; U.S. Patent US5684156, issued October, 1968.</p>