Dissociative anesthetic agent?
Correct Answer: Ketamine
Description: Ans. b (Ketamine) (Ref: KD Tripathi, Pharmacology 6th, ed., 376; 344)Ketamine and tiletamine are the two dissociative anesthetics currently available.Ketamine is pharmacologically related to the hallucinogen phencyclidine; induces a so called 'dissociative anaesthesia' characterized by profound analgesia, immobility, amnesia with endoscopic, light sleep and feeling of dissociation from ones own body and the surroundings. The primary site of action is in the cortex and subcortical areas; not in the reticular activating system (unlike barbiturates). Respiration is not depressed, airway reflexes are maintained.KETAMINE (dissociative anaesthesia)# Phencyclidine (PCP) derivative.2# Primary site of action is thalamoneocortical projection.# Fast onset.# Dose-related unconsciousness and dissociative state analgesia.# Strong analgesic.2# Not as amnestic as benzodiazepines.# No suppression of the CVS and RS.# May cause hallucinations and disturbing dreams, especially in adults and is its most common side-effect.# Intracranial tension is highly increased. 0# Potent bronchodilator.0# Dilates pupils and triggers nystagmus.# Increased salivation.# Increased muscle tone and purposeless movements of the extremities# Increased cerebral blood flow and intracranial pressure.# Dose:- IV: 2 mg/kg- IM:5-10 mg/kg0# Induction of choice for:- Asthmatics- Shock- Children (by intramuscular route) as an alternative to inhalational induction (inhalational is the method of choice for induction in children).- Constrictive pericarditis, cardiac tamponade, and right-to-left shunts.- Can be used as a sole agent for minor procedures (like I and D), burn dressings.- Preferred agent for patients with full stomach (pharyngeal and laryngeal reflexes are preserved).- Poor risk patients (ASA IV) (because of safety).- Depressed patients (they have better recovery after ketamine).PROPOFOL# Propofol preparation is derived from egg- extract.# It can induce nausea & vomiting# PROPOFOL should not be used as induction agent in the following situations:- Allergies: Patients with a history of previous allergic reaction to propofol or allergies to soybeans and eggs.- Pregnancy.- Hypercholesterolemia.- Muscle relaxants: There have been reports of severe bronchospasm in patients receiving atracurium after propofol. It is best to administer nonhistamine-releasing muscle relaxants.- Cardiovascular-challenged patients: Patients who are hypovolemic (i.e., trauma, dialysis) or who have cardiovascular disease may not tolerate the decrease in MAP and myocardial depression associated with propofol.# It is not contraindicated in porphyria.
Category:
Anaesthesia
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