Clonidine
OUH PAIN TEAM or ICU PRESCRIPTION ONLY
Mechanism of action: Clonidine is a centrally acting alpha2-adrenergic agonist. It has been used to treat hypertension but is now more commonly used for sedation or analgesia.
Presentation: tablet, solution for injection
Suggested initial dose: 25mcg three times a day for adults over 50kg with normal hepatic and renal function. Maximum dose 100mcg tds. Dose often limited by hypotension or sedation.
Higher doses must be weaned and not stopped abruptly before patient discharge. Clonidine must NOT be given as a TTO.
Oral absorption: Bioavailability of 75-88%, with peak plasma levels attained at 60-90 mins
Protein binding: 20%
Metabolism: Only 40% of a dose is metabolised, with the rest renally excreted. Inactive metabolites are produced mainly by CYP2D6 with contributions from CYP1A2 and CYP3A4
Elimination: 60% is excreted in urine unchanged (so caution needed in renal failure)
Half-life: 12-16 hours (reduced in pregnancy)
Further prescribing information (side effects, contraindications, interactions):