LC-MS/MS METHOD FOR THE ADHERENCE MONITORING AND DRUG SURVEILLANCE IN CHRONIC OPIOID THERAPY

Opioid analgesics are the most potent pain medications available, therefore they are often used for the treatment of chronic malignant and non‐malignant pain. Among them oxycodone, a semi-synthetic narcotic analgesic, is one of the most prescribed. Though oxycodone is approximately equivalent to morphine in its potency, it provides a longer analgesic action and causes less hallucinations than morphine. It has pharmacological and side effects such as analgesia, euphoria, sedation and relaxation, which are similar to effects from other opiate receptor agonists such as morphine and codeine, and the potential for addiction is similar to morphine. Monitoring adherence with chronic opioid therapy is a critical yet difficult task because this approach is often fraught with complex pharmacological, psychological, social and legal issues. The strong addictive potential of opioid analgesics requires close monitoring of patients on pain management therapy for possible non‐compliance with prescriptions, use for recreational purposes, and for testing the intake of non‐prescribed or illicit opioids. Natural, semi‐synthetic and synthetic opioids have dissimilar chemical structures and they undergo extensive metabolism: phase one metabolic reactions of opioids can produce compounds with structures similar to other, non‐prescribed medications. Thus, only detailed and concurrent analysis of parent drugs and metabolites can provide accurate clinical information regarding patient compliance. This study, as a part of a broader research project on abuse and misuse of opioid drugs, is aimed at the development of an analytical approach suitable for the drug monitoring and surveillance of opioid drugs used for chronic pain management treatments, focusing in particular on oxycodone, oxymorphone and fentanyl. Thus, an analytical method, based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for the identification and quantitation of those compounds and their metabolites in plasma was developed. Preliminary results are promising in terms of extraction yields and sensitivity for all the analytes. The method is currently undergoing validation and seems suitable for the adherence monitoring and drug surveillance of patients undergoing chronic pain management therapy with opioid drugs.