| Farmacología de la oxicodona: ¿Explica por qué la oxicodona se ha convertido en un opioide con fuerte éxito de venta? |
Pharmacology of oxycodone: does it explain why oxycodone has become a bestselling strong opioid?
Kim K. Lemberga, Tarja E. Heiskanenb, Vesa K. Kontinena, Eija A. Kalsoa,
Scandinavian Journal of Pain 1, S1 (2009) S18 S23
As morphine, oxycodone is a m-opioid receptor agonist with a significantly different pharmacokinetic profile compared with morphine. It seems that oxycodone is able to compensate its lower binding affinity for the m-opioid receptor compared with that of morphine by active transport to the central nervous system. Although the analgesic properties of oxycodone are mainly due to its own activity, cytochrome (CYP) inhibitors and inductors may change oxycodone-induced analgesia as a result of higher or lower, respectively, oxycodone concentrations.
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| Nuevos principios terapéuticos de los efectos adversos sobre el tracto gastrointestinal alto y bajo en lo pacientes tratados con analgésicos opioides |
New therapeutic principles for adverse effects on upper and lower gastrointestinal tract in patients treated with opioid analgesics
Torill Kaasa, Luis Romundstad, Harald Breivik
University of Oslo and Rikshospitalet, Department of Anaesthesiology and Intensive Care, 0027 Oslo, Norway
Scandinavian Journal of Pain 1, S1 (2009) S12 S17
Recent large scale surveys document that patients on opioid analgesics suffer adverse effects from increased tone in sphincters of both the upper and lower part of the gastrointestinal tract, decreased secretions into and increased absorption of fluids out of the bowel. These adverse effects often cause patients to discontinue opioid analgesics. Also patients treated with opioids for acute pain after surgery and in the intensive care units suffer gastrointestinal adverse effects. Constipation is the most common adverse effect of opioids. Most patients self-medicate with over-the-counter laxatives but suffer unpredictable responses and bothersome adverse effects of laxatives. Potent prescription laxatives may further adversely impact quality of life of chronic pain patients. Opioid-induced dysfunctions of the upper gastrointestinal tract are often misinterpreted by health care providers, and they are not relieved by laxatives. Two therapeutic developments make specific and effective prophylaxis and treatment possible: (1) Peripherally acting opioid antagonists that do not cross the blood brain barrier (methylnaltrexone and alvimopan), and (2) the opioid antagonist naloxone added to an opioid agonist in prolonged-release oral formulations (tilidin or oxycodone). Orally administered prolonged-release naloxone is almost completely eliminated during the first-pass through the liver and will therefore not reach opioid receptors in the central nervous system. These drugs relieve both upper and lower gastrointestinal adverse effects of opioid agonists, although their effects on constipation have been the focus of most clinical studies. These new pharmacological principles promise improved management of pain with opioids both for acute and chronic pain conditions.
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| Papel de la oxicodona y de oxicodona/naloxona en al tratamiento del dolor por cáncer |
Role of oxycodone and oxycodone/naloxone in cancer pain management.
Leppert W.
Department of Palliative Medicine, Poznań University of Medical Sciences, Osiedle Rusa 25 A, PL 61-245 Poznań, Poland. wojciechleppert@wp.pl
Pharmacol Rep. 2010;62(4):578-91. Abstract
Oxycodone is a valued opioid analgesic, which may be administered either as the first strong opioid or when other strong opioids are ineffective. In case of insufficient analgesia and/or intense adverse effects such as sedation, hallucinations and nausea/vomiting a switch from another opioid to oxycodone might be beneficial. Oxycodone is administered to opioid-naive patients with severe pain and to patients who were unsuccessfully treated with weak opioids, namely tramadol, codeine and dihydrocodeine. Oxycodone effective analgesia may be attributed to its affinity to μ and possibly κ opioid receptors, rapid penetration through the blood-brain barrier and higher concentrations in brain than in plasma. Oxycodone displays high bioavailability after oral administration and may be better than morphine in patients with renal impairment due to the decreased production of active metabolites. Recently an oral controlled-release oxycodone formulation was introduced in Poland. Another new product that was launched recently is a combination of prolonged-release oxycodone with prolonged-release naloxone (oxycodone/naloxone tablets). The aim of this review is to outline the pharmacodynamic and pharmacokinetic properties, drug interactions, dosing rules, adverse effects, equianalgesic dose ratio with other opioids and clinical studies of oxycodone in patients with cancer pain. The potential role of oxycodone/naloxone in chronic pain management and its impact on the bowel function is also discussed.
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