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Drug Update Tapentadol Sujatha MB1 www.kjoonline.org Govt. Medical College Thrissur,Kerala, India 1 Assoc. Professor of Pharmacology Correspondence should be sent to: [email protected] Introduction Tapentadol is a novel centrally acting synthetic analgesic with mu-opioid receptor agonism and norepinephrine reuptake inhibition in a single molecule. It is approved for the treatment of moderate to severe pain in adults, 18 years of age or older. It is well known that mu-opioid receptor agonists and norepinephrine reuptake inhibitors have analgesic effects, although the pain conditions in which these two drug classes are most efficacious may be different. It appears that, overall, mu-opioid agonists are predominantly effective against acute, moderate to severe pain, whereas, norepinephrine reuptake inhibitors are particularly effective against chronic pain.This implies that a compound that combines both mechanism of action holds the promise of being effective against a large spectrum of pain conditions,ranging from acute to chronic pain. Chemical structure Chemically, Tapentadol is 3-3(dimethylamino)-1(ethyl-2-methylpropyl) phenol monohydrochloride.(Figure. 1) Mechanism of action Available online at www.kjoonline.org Quick response code It is structurally and mechanistically similar to Tramadol .It displays a dual mode of action, has mild opioid activity and possesses monoamine reuptake inhibitor activity also. (Figure. 2) Combining mu-opioid receptor agonism with monoamine reuptake inhibition is an approach to improve the therapeutic range of opioids. The different complementary mechanism of action may additively or even synergistically enhance the analgesic efficacy and or attenuate the side effect of mu-opioid receptor agonists by reducing the requirement for mu-opioid receptor activation.(Opioid sparing effect). The facilitation of mono aminergic transmission in descending pain inhibitory pathways in the spinal cord seems to be an important mechanism because compounds that block the reuptake of norepinephrine and/or serotonin are efficacious in the treatment of chronic painful conditions and can enhance the analgesic effect of morphine. This is of particular relevance because neuropathic pain is generally considered to be unresponsive to opiates and or difficult to treat effectively because of mu- opioid receptor related side effects. Attempts to circumvent this problem initially led to the development of Tramadol. Tramadol is an atypical, racemic opioid that combines weak mu-opioid receptor(MOR) activation with inhibition of norepinephrine and serotonin reuptake. This combination of complementary mechanisms of action results in potent analgesic activity. Thus the broad analgesic profile of Tapentadol and its relative resistance to tolerance development may be due to a dual mode of action consisting of both Mu-opioid receptor activation and Nor epinephrine reuptake inhibition. Kinetics Kerala Journal of Orthopaedics 2012;25:119-122 © Kerala Journal of Orthopaedics Figure. 1. Chemical structure of Tapentadalol Kerala Journal Of Orthopaedics Volume 25 | Issue 2 | July 2012 Tapentadol is administered orally. It is metabolised predominantly by glucuronidation. The metabolite is devoid of any analgesic activity and is mainly excreted in urine in the conjugated form. The plasma half life is approximately 4 hrs after oral administration. 119 Drug Update Sujatha et.al: Tapentadol Figure. 2. Mechanism of action of Tapentadalol Therapeutic use Tapentadol immediate release tablets have been approved by the FDA in 2008 for the relief of moderate to severe acute pain in adults and in 2011, for chronic pain in an extended release form. The approval was based on data from clinical studies involving more than 2,100 patients. This showed that Tapentadol provided significant relief of moderate to severe acute pain compared to a placebo and that the medicine was generally well tolerated. The studies were conducted in different patient groups, including those who had a bunionectomy, a standard foot surgery associated with predictable levels of moderate to severe pain, and in those with pain from end-stage joint disease. 120 (Figure courtesy: Medscape.com) A Phase 3 safety study of Tapentadol immediate-release tablets evaluated Tapentadol in patients with low back pain or pain from osteoarthritis of the hip or knee. It demonstrated that Tapentadol offers pain relief and is generally well tolerated. All trials utilised a 0-10 point scale for pain intensity (none to worst) and 0-5 point scale for pain relief (none to complete). Patients were assessed at time intervals and the sum of numerical values for these pain scales were the basis of evaluating efficacy. Secondary endpoints of total pain relief from baseline, time to pain relief, time to first rescue medication and the need for rescue medication were important clinically relevant endpoints. These published phase II and phase III studies used active control medications including Oxycodone, morphine or NSAIDs. Kerala Journal of Orthopaedics Volume 25 | Issue 2 | July 2012 Drug Update Sujatha et.al: Tapentadol Adverse effects The most common side effects reported with Tapentadol are nausea, vomiting, dizziness, headache & somnolence. In clinical trials, Tapentadol has been shown to provide equianalgesic effect with a lower incidence of side effects compared to Oxycodone and morphine. Precautions & contraindications Tapentadol is contraindicated in any situation where muopioid receptors are contraindicated. ie. in significant respiratory depression, acute or severe bronchial asthma, in patients with paralytic ileus or in patients concurrently using or within 14 days of using monoamine oxidase inhibitors. every 4-6 hrs depending upon pain intensity. Extended release tablets – 100-250 mg twice daily. Conclusion Tapentadol is a new analgesic drug with a dual mode of action and is effective in the treatment of both acute and chronic moderate to severe pain in adults. Its dual mode of action provides analgesia at similar levels of more potent narcotic analgesics with more tolerable side effect profile. Patients receiving other opioid analgesics, general anaestetics, Phenothiazines, Tranquilizers or other CNS depressants concomitantly with Tapentadol may exhibit an additive CNS depression. When such combined therapy is contemplated, a dose reduction of one or both agents should be considered. Like other drugs with mu-opioid agonist activity, Tapentadol should not be used in patients with head injury, increased intracranial tension etc. Tapentadol should be used with caution in patients with pancreatic or biliary tract disease and moderate hepatic impairment. Tapentadol should be prescribed with care in patients with a history of seizure disorder or any condition that would put the patient at risk of seizure. The development of a potentially life threatening serotonin syndrome may occur with the concurrent use of serotonergic drugs like Selective serotonin reuptake inhibitors(SSRI), Serotonin-norepinephrine reuptake inhibitors(SNRI), Triptans etc. Because elderly patients are more likely to have decreased renal and hepatic function, consideration should be given to start elderly patients with the lower range of recommended doses. Tapentadol can be abused in a manner similar to other opioid agonists. This risk is increased with concurrent abuse of Tapentadol with alcohol and other substances. Monitor patients closely for signs of abuse and addiction. Tapentadol may impair the mental or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. Dosage and administration Tapentadol immediate release tablets - 50mg- 100mg orally Kerala Journal Of Orthopaedics Volume 25 | Issue 2 | July 2012 References 1. Ballantyne JC and Mao J (2003) Opioid therapy for chronic pain. N Engl J Med 349: 1943–1953. 2. Kalso E, Edwards JE, Moore RA, and McQuay HJ (2004) Opioids in chronic noncancer pain: systematic review of efficacy and safety. Pain 112: 372–380.Thomas M. Tzschentke. 3. Thomas Christoph, Babette Kögel, Tapentadol HCl: a Novel ì-Opioid Receptor Agonist/Nor epinephrine Reuptake Inhibitor with Broad-Spectrum Analgesic Properties, Journal of Pharmacology & Experimental Therapeutics , vol.323,no.1265-276,2007. 4. Stephen E. Daniels, and Michael Golf, Clinical Efficacy and Safety of Tapentadol Immediate Release in the Postoperative Setting, in The Journal of American Podiatric Medical Association 102(2):139148, 2012. 5. FDA Approves Tapentadol Immediate-Release Tablets for Relief of Moderate to Severe Acute Pain, November 21, 2008. Retrieved on November 24, 2008. 6. Two New Analgesics May Help Patients After Bunionectomy”. Journal of Anaesthesiology Clinical Pharmacology. September 26, 2006. 7. Kleinert, R; Lange, C; Steup, A; Black, P; Goldberg, J; Dejardins, P. “Single Dose Analgesic Efficacy of Tapentadol in Postsurgical Dental Pain: The Results of a Randomized, Double-Blind, 121 Drug Update Sujatha et.al: Tapentadol Placebo-Controlled Study”. International Anesthesia Research Society Vol. 107, No. 6, December 2008. 8. Regina Kleinert, , Claudia Lange, , Achim Steup, Single Dose Analgesic Efficacy of Tapentadol in Postsurgical Dental Pain: The Results of a Randomized, Double-Blind, Placebo-Controlled Study, Journal of Anesthesia & Analgesia, December 2008 vol. 107 no. 6 20482055. 9. 11. Deidre M.Pierce, Emmanuel Shipstone, Pharmacology update: Tapentadol for Neuropathic pain In American Journal of Hospice & Palliative Medicine,Feb.5,2012. 12. Cepeda, M. Soledad MD, PhD * ; Sutton, Alex PhD † ; Weinstein, Rachel PhD * ; Kim, Myoung PhD, Effect of Tapentadol Extended Release on Productivity: Results From an Analysis Combining Evidence From Multiple Sources-In Clinical Journal of Pain: January 2012 - Volume 28 - Issue 1 - p 8–13. doi: 10.1097/AJP.0b013e3182201983. An update on analgesics Br J Anaesth July 1, 2011 107:19- 24 10. Tschentke, T.M. et al. “Tapentadol Hydrochloride.” Drugs of the Future. 2006, Vol. 31, Issue 12, p. 1053. DOI: 10.1358/ dof.2006.031.12.1047744 Source of funding: Nil; Conflict of interest: Nil Cite this article as: Sujatha MB. Tapentadol.Kerala Journal of Orthopaedics 2012;25:119-122 122 Kerala Journal of Orthopaedics Volume 25 | Issue 2 | July 2012