1 / 16

CLONIDINE

CLONIDINE. www.anaesthesia.co.in. email: anaesthesia.co.in@gmail.com. * centrally acting selective, partial alpha adrenergic agonist (220:1 alpha 2 to alpha 1 ) * Stimulates inhibitory alpha 2 adrenoceptors to reduce central neural transmission in spinal neurons.

lamont
Download Presentation

CLONIDINE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CLONIDINE www.anaesthesia.co.in email: anaesthesia.co.in@gmail.com

  2. * centrally acting selective, partial alpha adrenergic agonist (220:1 alpha2 to alpha1) * Stimulates inhibitory alpha2 adrenoceptors to reduce central neural transmission in spinal neurons

  3. Commercial Availability- as preservative- free ClonidineHCl 150µg/ml solution single dose ampoules Storage-below 25°C Mechanism of action • produce clinical effects by binding to alpha2 receptors. • 3 subtypes • alpha2A- mediate sedation, analgesia, sympatholysis. • alpha2B- vasoconstriction and possibly antishivering effects. • alpha2C- may be responsible for startle response.

  4. PHARMACODYNAMICS • Cardiovascular effects • decreased BP ( greater fall in systolic) • decreased HR • In chronically treated patients – - SVR little affected - CO initially decreased, returns toward pre-drug levels with time. 2. Respiratory effects • minimal depressant effect on ventilation • do not potentiate depressant effects of opioids

  5. Pharmacokinetics • Oral • rapidly absorbed • peak plasma conc.=60-90min • Et1/2 = 9-12 hrs 2. Intravenous– highly lipid soluble & readily distributes into extra vascular sites including CNS

  6. Pontine locus ceruleus – sedation • Medullary vasomotor response – peripheral vasodilation, decreased BP, HR and CO. • Modification of K+ channels in CNS: (hyperpolarization of cell membranes) - profound decreases in anaesthetic requirements. • Neuraxial administration- inhibits spinal substance P release & nociceptive neuron firing due to noxious stimulation.

  7. USES 1. Preanaesthetic medication: Oral clonidine in preoperative period- a) blunts reflex tachycardia associated with direct laryngoscopy & intubation b) decreases intraoperative lability of BP & HR c) decreases plasma catecholamine concentrations d) dramatically decrease anaesthetic requirement for inhaled (MAC) & injected drugs

  8. 2. Analgesia: • Preservative- free clonidine administration into the epidural or subarachnoid space produces dose-dependent analgesia (avoiding side effects of opioids) - due to activation of postsynaptic alpha2 receptors in substantia gelatinosa of spinal cord - Side Effect: hypotension, sedation, dryness of mouth • Addition of clonidine 1µ/kg to lidocaine in Bier’s Block enhances post-operative analgesia • Intra- articular administration of clonidine produces analgesia after knee arthroscopies.

  9. 3. Chronic pain: - transdermal clonidine shown to decrease pain in diabetic neuropathy • intractable pain following spinal cord injury • reported to possess peripheral analgesic properties

  10. 4. Prolonging the effects of regional anaesthesia: • Prolonged duration of sensory & motor blockade in subarachnoid block. • oral clonidine 150-200µg admn. 1-1.5 hrs before institution of S.A.B has same effect Increased intensity of Peripheral Nerve Blocks * addition of clonidine to local anaesthetic

  11. 5. Protection against peri-operative Myocardial ischaemia: • Decrease in overall mortality (superior to beta-blockers) • 0.2mg oral or transdermal patch in evening before or on morning of surgery in patients at risk for CAD and continued for 4 days post-operatively

  12. 6. Diagnosis of pheochromocytoma: • oral 0.3mg decreases plasma conc. in normal patients but not in presence of pheochromocytoma 7. Treatment of shivering: • 75µg i.v. clonidine stops shivering (reflects ability to inhibit central thermoregulatory control) • 150µg i.v. effective in preventing shivering in patients receiving epidural anaesthesia

  13. 8. Opioid & alcohol withdrawal syndrome: • Clonidine 10µg/kg i.v. decreases sympathetic NS activity associated with cardiovascular stimulation & attenuates increase in plasma catecholamine concentrations when naloxone is administered during G.A. to pt. addicted to opioids • Effective in T/t of Alcohol withdrawal syndrome in pt. not responding to high doses of BZDs or opioids

  14. SIDE- EFFECTS 1) Sedation 2) Xerostomia 3) Bradycardia (often requires treatment with anticholinergic) 4) Retention of sodium and water 5) Skin rashes 6) Impotence 7) Orthostatic hypotension (rare)

  15. DOSAGE GUIDELINES (healthy adults) 1. ORAL- 30µg/kg 2. INTRATHECAL- 15-30µg added to local anaesthetic agents (max. 1µg/kg) 3. EPIDURAL-50µg or 1µg/kg, whichever is lower (max. 2µg/kg) 4. INTRA-ARTICULAR- 150µg or 2µg/kg 5. INTRAVENOUS *50-75µg or 1µg/kg, whichever is lower slowly 15 minutes prior to surgery *Post operative/ epidural shivering- 30µg slow i.v. * H.T. Crisis-150-300µg slow i.v. over 10 min (max. 3µg/kg) 6. CONTINUOUS EPIDURAL INFUSION: starting dose-30µg/h, titrated according to response

  16. CONTRAINDICATIONS • Known hypersensitivity • Brady-arrythmias or heart block • Cardiovascular/ haemodynamic instability • Patients on anticoagulant therapy or with bleeding diathesis • Local infection at site of epidural injection • Obstetric patients (category C) • Lactating patients

More Related