Opioids fentanyl

Case Definition Opioids (Fentanyl, Etorphine, or Others)." March 11,2005. 

Tertiary arylacetamides appear to undergo hydrolysis to a very limited extent only. Hydrolysis of the synthetic opioid fentanyl (4.117) to despropa-noylfentanyl (4.118) was a very minor pathway in humans [76], No metabolites resulting from amide hydrolysis were detected for the fentanil analogues alfentanil (4.119) and sufentanil (4.120) [77], for which oxidative N-dealkylation was the main metabolic pathway. 

Phenothiazines with shorter side chains have considerable H -receptor-blocking action and have been used for relief of pruritus or, in the case of promethazine, as preoperative sedatives. The butyrophenone droperidol is used in combination with an opioid, fentanyl, in neuroleptanesthesia. The use of these drugs in anesthesia practice is described in Chapter 25. 

Clinical use The indications for levobupivacaine include wound infiltration (0.25 % solution), nerve conduction block (0.25 - 0.5 %), spinal analgesia (0.5 %) and epidural anesthesia (0.5 to 0.75 %). For labour analgesia, lower concentrations of levobupivacaine are recommended when administered as epidural injection (0.125 to 0.25 % up to 25 mg) or infusion (0.25 %). The maximum dose for ilioinguinal or iliohypogastric block in children is 1.25 mg/kg/side (0.25 to 0.5 % solutions). For postoperative pain management, levobupivacaine can be applied epidurally in combination with the opioids fentanyl or morphine or with the a2-agonist clonidine. 

Omeprazole, like cimetidine, can impair benzodiazepine metabolism and lead to adverse effects (SEDA-18, 43). Other drugs, including antibiotics (erythromycin, chloramphenicol, isoniazid), antifungal drugs (ketoconazole, itraconazole, and analogues), some SSRIs (fluoxetine, paroxetine), other antidepressants (nefazodone), protease inhibitors (saquinavir), opioids (fentanyl), calcium channel blockers (diltiazem, verapamil), and disulfiram also compete for hepatic oxidative pathways that metabolize most benzodiazepines, as well as zolpidem, zopiclone, and buspirone (SEDA-22,39) (SEDA-22,41). 

A self-adhesive skin patch formulation which releases the opioid fentanyl (25 mg/h for 72 h) transdermally is also available for pain relief in palliative care. 

Like other opioids, fentanyl can cause pruritus. Prophylactic intravenous ondansetron 8 mg with hyperbaric bupivacaine 7-10 mg and fentanyl 25 pg significantly reduced the incidence of intrathecal fentanyl-induced pruritus in 125 patients undergoing knee arthroscopy or urological surgery in a randomized, double-blind, placebo-controlled trial (17). The incidence of pruritus was 39% with ondansetron and 68% with placebo. 

The minimum alveolar concentrations of sevoflurane required to suppress movements and adrenergic responses to surgery in the presence of the potent opioid fentanyl have been quantified in 226 adults (59). Fentanyl 3 ng/ml and 6 ng/ml reduced sevoflurane requirements to suppress movement to pain by 61% and 74%, respectively, and requirements to suppress the adrenergic responses to pain by 83% and 91%, respectively. There was no further reduction in sevoflurane requirements at concentrations of fentanyl above 6 ng/ml. The degree of interaction was similar to that seen in previous studies of other volatile anesthetic + opioid combinations. 

Opioids Fentanyl, sufentanil, and alfentanil are frequently used prior to anesthesia and surgery as a sedative and analgesic, as well as a continuous infusion for primary anesthesia. Because opioids rarely affect the cardiovascular system, they are particularly useful for cardiac surgery and other high-risk cases. Opioids act directly on spinal cord receptors, and are frequently used in epidurals for spinal anesthesia. Side effects may include nausea and vomiting, itching, and respiratory depression. 

Consider also Opioids Fentanyl and related drugs + Azoles , below. 

Scheme 33 A Structures of the synthetic opioids fentanyl (165), carfentanil (166) and sufentanil (167), B Synthesis of the synthetic opioid alfentanil (172) [128]...

In a multicenter, double-blind, placebo-controlled study of the effects of intravenous flumazenil 0.7 mg in reversing the effects of midazolam, 82% of 131 flumazenil-treated patients had complete reversal of sedation, compared with 15% of 65 placebo-treated patients. However, flumazenil reversed midazolam-induced amnesia in only 60% of patients. Dizziness (10%) and nausea (9%) were the most common adverse effects [96 ]. Similar results were obtained in a double-blind, placebo-controlled study in patients who had been given midazolam plus an opioid (fentanyl, pethidine, or morphine) [97 ], intravenous diazepam [98 "], or diazepam plus an opioid [99 ]. 

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