Psychopharmacology
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It has been known that anesthetic adjuvants such as dexamethasone or ketamine might change mood. This study aimed to investigate the effects of a single dose of each drug individually along with their combined usage on postoperative mood changes in patients undergoing gynecologic surgery. ⋯ A single dose of ketamine (0.5 mg/kg) with or without combination with dexamethasone (0.1 mg/kg) give iv 5 min after induction of general anesthetic produced significant improvement in the postoperative mood scores. A single intravenous dose of dexamethasone (0.1 mg/kg) alone did not change postoperative mood scores. The VAS for pain 24 h after surgery and the PCA consumption was significantly lower in patients who received combination of both drugs.
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Cannabinoid receptor agonists such as delta-9-tetrahydrocannabinol (Δ9-THC) enhance the antinociceptive potency of mu opioid receptor agonists such as morphine, indicating that opioid/cannabinoid mixtures might be effective for treating pain. However, such enhancement will be beneficial only if cannabinoids do not also enhance adverse effects of opioids, including those related to abuse. In rhesus monkeys, cannabinoids fail to enhance and often decrease self-administration of the mu opioid receptor agonist heroin, suggesting that opioid/cannabinoid mixtures do not have greater reinforcing effects (abuse potential) compared with opioids alone. Previous studies on the self-administration of opioid/cannabinoid mixtures used single-response procedures, which do not easily differentiate changes in reinforcing effects from other effects (e.g., rate decreasing). ⋯ Overall, these results extend previous studies to include choice behavior and show that cannabinoids do not substantially enhance the reinforcing effects of mu opioid receptor agonists.