Ketamine Opiates

Wu YH, Lin KL, Chen SC, Chang YZ (2008) Simultaneous quantitative determination of amphetamines, ketamine, opiates and metabolites in human hair by gas chromatography/mass spectrometry. Rapid Commun Mass Spectrom 22(6) 887-897... 

Prior use of benzodiazepines or opiates limits the psychotomimetic effects of ketamine. There has been a double-blind, placebo-controlled study of the role of lorazepam in reducing these effects after subanesthetic doses of ketamine in 23 volunteers who received lorazepam 2 mg or placebo, 2 hours before either a bolus dose of ketamine 0.26 mg/kg followed by an infusion of 0.65 mg/kg/hour or a placebo infusion (438). The ability of lorazepam to block the undesirable effects of ketamine was limited to just some effects. It reduced the ketamine-associated emotional distress and perceptual alterations, but exacerbated the sedative, attention-impairing, and amnesic effects of ketamine. However, it failed to reduce many of the cognitive and behavioral effects of ketamine. There were no pharmacokinetic interactions between subanesthetic doses of ketamine and lorazepam. 

Phencyclidine (PCP) and the related compound ketamine have a mixture of clinical effects that reflects their complex pharmacology. Although acting on a specific subset of serotonin-type (HT-2) receptors in the forebrain,22 PCP also has affinity for cholinergic, opiate, and dopamine receptors. This may explain PCP s ability to produce subjec-... 

Wu Y-H, Lin K-L, Chen S-C, Chang Y-Z (2008) Integration of GC/EI-MS and GC/NCI-MS for simultaneous quantitative determination of opiates, amphetamines, MDMA, ketamine, and metabolites in human hair. J Chromatogr B 870 192-202... 

The addition of ketamine as an opiate sparer, 1.5 or 5 mg per bolus morphine dose, has been studied in 58 patients undergoing transthoracic heart and lung surgery, a procedure that is associated with severe pain [122 ]. Those who took ketamine used 50% less morphine and required less rescue diclofenac for pain control. Pain scores were consistently lower with ketamine, despite reduced amounts of morphine administered. Respiratory parameters were much better with ketamine none compared with seven patients requiring oxygen for hypoxia. The... 

Ketamine has also been studied as an adjuvant to lidocaine intravenous regional anesthesia for hand surgery in 40 patients who received ketamine 0.1 mg/kg either as an adjuvant to the lidocaine or as an intravenous injection [26 ]. There were no significant differences in tourniquet pain or opiate requirements, either intraoperatively or during the recovery period. There were no difference in the incidence of psychotomimetic effects and satisfaction was high in both groups. The authors felt that it would be unethical to include a control group, as ketamine has already been shown to be superior to placebo. However, this makes the conclusions hard to interpret. 

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