Clonidine
Drug | Clonidine |
Brand names | Catapresan ®, Catapres ®, Dixarit ®, Catapres-TTS ®, Catapres-TTS-1 ®, Duraclon ®, Kapvay ® |
Indications | • Agitated delirium • Analgesia • Hypertension, hypertensive crisis/emergency |
Mechanism of action | Clonidine is primarily a centrally acting alpha-2 agonist. Stimulation of alpha-2 adrenoceptors in the ventromedial and rostral-ventrolateral areas of the medulla result in the blood pressure lowering effect. |
Effects | Potent blood pressure lowering effect. Pain relief. |
Delivery | IV, IM, PO, transdermal |
Dose | Injection IV: • 150 μg in 1 ml vial. Dilute with 10 ml of normal saline and give by slow injection over 5-10 minutes. Dilute immediately before use. PO: Alternatives: Dixarit 25 μg tablets. Catapress 150 μg tablets. Dose: 75 μg daily increased as required to up to 900 μg/day. Transdermal (one patch lasts for a week): • Catapress TTS-1 (0.1 mg/24hrs). • Catapress TTS-2 (0.2 mg/24hrs) • Catapress TTS-3 (0.3 mg/24hrs) Dosage in renal failure and renal replacement therapy: Dose as in normal renal function |
Adverse effects | Excessive sedation. Confusion. Hallucinations. Hypotension. Bradycardia. AV-block. Constipation |
Contra indications | Bradycardia. |
Caution | • Clonidine may induce severe hypotension. • Clonidine is not recommended in most patients with severe cardiovascular disease or in those who are otherwise haemodynamically unstable. The benefit of its administration in these patients should be carefully balanced against the potential risks resulting from hypotension. • Withdrawal of clonidine may lead to rebound hypertension. Withdraw slowly. • Simultaneous use of tricyclic antidepressants reduces the effect of clonidine. • Clonidine increases the CNS-depressive effects of alcohol and sedatives. |