Pharmacology of opioids
Pamela E. Macintyre, Stephan A. Schug in Acute Pain Management, 2014
Structurally similar to methadone, only the dextrorotatory (R isomer) form has any analgesic activity (dextropropoxyphene). Often administered in an oral formulation in combination with paracetamol or aspirin, these preparations may be no more effective than paracetamol or aspirin alone (ANZCA and FPM, 2010). Toxicity, with hallucinations, delusions, and confusion, may occur with accumulation of the renally excreted active metabolite norpropoxyphene, particularly in the older patient or in patients with renal impairment (Barkin et al., 2006; Smith, 2011). Cardiotoxicity has also been reported, with prolongation of the QT interval and the risk of torsades des pointes and death. In view of these significant disadvantages and risks, and limited analgesic efficacy, the use of dextropropoxyphene should be discouraged (Barkin et al., 2006). It has been or is being withdrawn from the market in many countries.
Pharmacology of Opioids
Pamela E. Macintyre, Stephan A. Schug in Acute Pain Management, 2021
Structurally similar to methadone, only the dextrorotatory (R isomer) form has any analgesic activity (dextropropoxyphene). Often administered in an oral formulation in combination with paracetamol or aspirin, these preparations may be no more effective than paracetamol or aspirin alone (Schug et al, 2020). Toxicity, with hallucinations, delusions, and confusion, may occur with accumulation of the renally excreted active metabolite norpropoxyphene, particularly in the older patient or in patients with renal impairment. Cardiotoxicity has also been reported, with prolongation of the QT interval and the risk of torsades des pointes and death. In view of these significant disadvantages and risks, and limited analgesic efficacy, the use of dextropropoxyphene should be discouraged (Schug et al, 2020). It has been or is being withdrawn from the market in many countries.
Cancer pain in older people
Nigel Sykes, Michael I Bennett, Chun-Su Yuan in Clinical Pain Management, 2008
Drug combinations should, on the whole, be avoided in elderly patients. Although codeine causes confusion and constipation in older subjects,136 Moore et al.137[I] found that the combination of codeine 60 mg and acetaminophen 600/650 mg is a more effective analgesic than acetaminophen 600/650 mg alone. The addition of codeine to paracetamol increased the number of patients achieving at least 50 percent pain relief by 12 percent. The Cochrane Systematic Review concluded that paracetamol is an effective analgesic, associated with a low incidence of side effects. The addition of codeine 60 mg to paracetamol produces additional pain relief even in single oral doses but may be accompanied by an increase in drowsiness and dizziness.138[I] Coproxamol, once the drug of choice combining paracetamol and dextropropoxyphene, became unpopular after a large number of successful suicide attempts and may cause confusion and drowsiness in older people because of its long elimination half-life.139 The Cochrane Systematic Review of dextropropoxyphene alone and in combination with paracetamol focused on the effectiveness of the combination in relieving postoperative pain. It found that single-dose dextropropoxyphene and paracetamol were as effective as tramadol in postoperative pain and were associated with a lower incidence of adverse effects. Although it concluded that the same dose of paracetamol combined with codeine appeared to be more effective than paracetamol alone, there was an overlap in the 95 percent confidence intervals, allowing room for this conclusion to be challenged. This review also found that the number needed to treat was lower for ibuprofen than for either the combination of dextropropoxyphene plus paracetamol or tramadol.140
The pharmacological interactions between direct-acting antivirals for the treatment of chronic hepatitis c and psychotropic drugs
Published in Expert Review of Clinical Pharmacology, 2018
Carlos Roncero, Jose Luis Villegas, Maria Martínez-Rebollar, Maria Buti
As a summary of the interactions between this combination regimen and the agents active over the nervous system, it should not be coadministered with the following drugs (see Table 3): Analgesics: dextropropoxypheneAnxiolytics: oral midazolam or triazolam.Antipsychotics: pimozide, quetiapine.Anticonvulsants: carbamazepine, eslicarbazepine, oxcarbazepine, phenobarbital, phenytoin, and primidone.Other: St John’s wort.
Comparative risk-benefit profiles of weak opioids in the treatment of osteoarthritis: a network meta-analysis of randomized controlled trials
Published in Postgraduate Medicine, 2022
Wei Li, Hongyi He, Zidan Yang, Ziying Wu, Dongxing Xie
Our findings indicated that tramadol and codeine were effective drugs for the treatment of OA, but involved considerable safety issues. Dextropropoxyphene was a relatively safe option among weak opioids but only showing limited benefits in pain relief. Dihydrocodeine exhibited a relatively good safety profile but its efficacy still warrants further investigation. Increasing the doses of tramadol may offer little added clinical benefit, but more harms.
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