Agitation ketamine

Phencyclidine (l-[l-phenylcyclohexyl] piperidine, PCP) was originally developed as an intravenous anesthetic in the 1950s. Used for this indication, it causes a trance-like state without loss of consciousness and was hence classified as a dissociative anesthetic. However, it was soon withdrawn from human use because it produced unpleasant hallucinations, agitation, and delirium. The product was later used in veterinary medicine. Ketamine, a chemically closely related substance, was developed to replace PCP and is stiU in use as a dissociative anesthetic in children. Ketamine is less potent than PCP, and its effects are of shorter duration. However, it may also cause hallucinations (see the section on ketamine in Chapter 7, Club Drugs ). Much of the ketamine sold on the street (special K, cat Valium) has been diverted from veterinarians offices. 

White et al. 1982). Benzodiazepines may be useful, particularly if agitation is present, although clinicians must be mindful of a possible interaction leading to a prolonged half-life for ketamine (Lahti et al. 1995 Lo and Gumming 1975). In general, because of the short half-life of ketamine, patients usually require observation only for several hours and can then be released home (Koesters et al. 2002). 

Obviously, we do not know what, if any, psychedelic experiences an animal may have in response to a ketamine dart. (Perhaps they experience K-Land and K-Hole just like humans.) Animals rarely become violent or agitated after being injected with ketamine, so it is unlikely to produce the psychotic symptoms observed in some human users. 

The most serious disadvantage to the use of ketamine is its propensity to evoke excitatory and hallucinatory phenomena as the patient emerges from anesthesia. Patients in the recovery period may be agitated, scream and cry, hallucinate, or experience vivid dreams. These episodes may be controlled to some extent by maintaining a quiet reassuring atmosphere in which the patient can awaken or if necessary by administering tran-quilizing doses of diazepam. 

The duration of the drug s action depends on the method of administration. Upon recovery from ketamine, the patient or user may be agitated, disoriented, restless, and tearful. This is called emergence delirium. Patients may continue to experience unpleasant dreams up to 24 hours after the drug has been taken. Flashbacks have been reported, and their incidence may be higher than with many hallucinogens.55... 

Sherwin TS, Green SM, Khan A, Chapman DS, Dannenberg B. Does adjunctive midazolam reduce recovery agitation after ketamine sedation for pediatric procedures A randomized, double-bhnd, placebo-controlled trial. Ann Emerg Med 2000 35(3) 229-38. 

Comparative studies Propofol and ketamine have been compared in procedural sedation in the Emergency Department [34. Patients were randomized to propofol 1+0.5 mg/kg every 3 minutes if needed ( =50) or the same doses of ketamine ( =47). There was a higher rate of subclinical respiratory depression with ketamine, but the number of clinical interventions in the two groups was the same. Recovery agitation was more common with the ketamine group than propofol (17% versus 4%), but procedural pain was less common (2.1% versus 6.0%). Recall and patient satisfaction were similar (13% versus 12% and 100% versus 100%). 

Propofol In a randomized study in 60 children who underwent interventional radiology and were allocated to propofol 0.5 mg/kg - -fentanyl 1 microgram/kg + ketamine 0.5 mg/kg ( = 30) or propofol 0.5 mg/kg - - fentanyl 1 microgram/kg + saline 0.9% ( = 30) intravenously, there was oxygen desaturation in three of those who received ketamine and nine of those who did not [80 ]. Those who received ketamine also had agitation n = 2) and tachycardia ( = 1), which did not occur in the other group. Nystagmus was also a common adverse reaction (19 cases versus... 

Ketamine Euphoria, stimulation, anxiety Agitation, anxiety Chronic use ... 

A further study reviewed 18 patients over a 3 year period with acute agitation and psychiatric illness requiring aero medical retrieval imder the mental health act [5(T]. Intravenous ketamine for sedation of patients was used as an alternative to a general anaesthetic and intubation. Patients were given up to two bolus doses of 0.5-1 mg/kg followed by an infusion of 1-1.5 mg/kg/hr. Only mild adverse events occurred with four patients having hypertension and tachycardia all of which spontaneously resolved. One patient vomited but there were no incidences of aspiration and no airway intervention was required. Thus ketamine could be considered as a safe alternative to general anaesthetic in this study population. 

Sondekoppam VR, Gandhi K, Batra YK. Etomidate induced agitation during intraoperative sedation. Saudi J Anaesth 2012 6 303-4. Lopez-Alvarez S, Mayo-Moldes M, Zaballos M, Iglesias BG, Blanco-Davila R. Esmolol versus ketamine-remifentanil combination for early postoperative analgesia after laparoscopic cholecystectomy a randomized controlled trial. Can J Anaesth 2012 59 442-8. 

Le Cong M, Gynther B, Hunter E, Schuller P. Ketamine sedation for patients with acute agitation and psychiatric illness requiring aeromedi-cal retrieval. Emerg Med J 2012 29 335-7. 

---