Pain
-
In order to assess the analgesia obtained from single oral doses of paracetamol alone and in combination with codeine in postoperative pain, we conducted a systematic review of randomised controlled trials. We found 31 trials of paracetamol against placebo with 2515 patients, 19 trials of paracetamol plus codeine against placebo with 1204 patients and 13 trials of paracetamol plus codeine against the same dose of paracetamol with 874 patients. Pain relief information was extracted, and converted into dichotomous information (number of patients with at least 50% pain relief). ⋯ In indirect comparisons of each with placebo it was 14 extra patients per 100. This was an NNT for adding codeine 60 mg of 9.1 (5.8-24). The results confirm that paracetamol is an effective analgesic, and that codeine 60 mg added to paracetamol produces worthwhile additional pain relief even in single oral doses.
-
Methadone is a synthetic opioid agonist considered a second choice drug in the management of cancer pain. Methadone has a number of unique characteristics including excellent oral and rectal absorption, no known active metabolites, high potency, low cost, and longer administration intervals, as well as an incomplete cross-tolerance with respect to other mu-opioid receptor agonist drugs. ⋯ Recent findings suggest that standard equianalgesic tables are unreliable for methadone titration in patients tolerant to high doses of opioid agonists and that switchovers should take place slowly and should be personalized. Future research has to better define the variation in both bioavailability and elimination of methadone in different patient populations, the interaction between methadone and the most commonly used drugs in cancer patients, the type and activity of potential methadone metabolites, and the equianalgesic doses between methadone and the most commonly used opioids.
-
Dynorphin A (DYN) peptides, administered into the central nervous system, have produced inconsistent analgesic actions in tests using thermal stimuli. This study examined antinociceptive effects of intravenous and intraplantar DYN-(2-17) against noxious pressure in rats with Freund's adjuvant-induced unilateral hindpaw inflammation. The effects of DYN-(2-17) were compared to those of the opioid agonists morphine. (D-Ala2,N-Methyl-Phe4,Gly-ol5)-enkephalin (DAMGO) and DYN-(1-17). ⋯ These findings suggest that intravenous DYN-(2-17) produces possibly centrally mediated, non-opioid antinociceptive effects against noxious pressure. At certain doses these effects are more potent in inflamed than in non-inflamed paws. In contrast to the opioid peptides DYN-(1-17) and DAMGO, DYN-(2-17) does not appear to have no peripheral antinociceptive actions.
-
Review Randomized Controlled Trial Clinical Trial
Experimental evaluation of the analgesic effect of ibuprofen on primary and secondary hyperalgesia.
The analgesic effect of systemic ibuprofen was investigated with two human experimental pain models: (i) static mechanical stimulation of the inter digital web between the 2nd and 3rd finger and (ii) primary and secondary hyperalgesia induced by a 7-min burn injury on the calf. In each double-blind, randomized, two-way cross-over study 20 healthy male volunteers received either ibuprofen 600 mg or placebo tablets. ⋯ Previous human experimental studies concerning the analgesic effect of NSAIDs are reviewed. Based on the previous literature and the present results we suggest that NSAIDs inhibit progressive tactile hypersensitivity but not the central sensitization itself.
-
Randomized Controlled Trial Clinical Trial
Blockade of peripheral neuronal barrage reduces postoperative pain.
Peripheral afferent neuronal barrage from tissue injury produces central nervous system hyperexcitability which may contribute to increased postoperative pain. Blockade of afferent neuronal barrage has been reported to reduce pain following some, but not all, types of surgery. This study evaluated whether blockade of sensory input with a long-acting local anesthetic reduces postoperative pain after the anesthetic effects have dissipated. ⋯ Additionally, subjects in the bupivacaine group self-administered fewer codeine tablets for unrelieved pain over 24-48 h postoperatively (P < 0.05). These data support previous animal studies demonstrating that blockade of peripheral nociceptive barrage during and immediately after tissue injury results in decreased pain at later time points. The results suggest that blockade of nociceptive input by administration of a long-acting local anesthetic decreases the development of central hyperexcitability, resulting in less pain and analgesic intake.