METHODS: The three hundred participants comprised 152 opioid naive subjects and 148 opioid dependent patients. Opioid naive subjects had not taken any opioids including morphine and methadone to their best knowledge and were presumed so after two consecutive negative urine screenings for drugs. All opioid dependent patients were stabilized in treatment, defined as having been enrolled in the program for more than one month with no change of methadone dosage over the past one month. Excluded from the study were individuals with chronic or ongoing acute pain and individuals with a history of analgesics ingestion within 3 d before the cold pressor test (CPT). Pain tolerance to CPT was evaluated at 0 h, and at 2, 4, 8, 12, and 24 h post-methadone dose.
RESULTS: Patients exhibited a significantly shorter mean pain tolerance time of 34.17 s (95% CI 24.86, 43.49) versus 61.36 (52.23, 70.48) [p < 0.001] compared with opioid naive subjects. Time-dependent mean pain tolerance was also significantly different when naive subjects were compared to patients (p = 0.016).
CONCLUSIONS: This study revealed hyperalgesia amongst patients on MMT, as manifested by their quicker hand withdrawal. The complaints of pain in this population should not be underestimated and the pain should be evaluated seriously and managed aggressively.
DESIGN, METHODS AND RESULTS: A case series of seven patients from Malaysian private and public hospital settings who had an adverse reaction with methadone is discussed.
DISCUSSION AND CONCLUSION: Despite methadone being an effective therapy for opioid dependence, there is a need for other alternative effective therapies, such as naltrexone, buprenorphine and the co-formulation of buprenorphine-naloxone, to be made available to physicians in both public and private sectors. There is need for individual treatment consideration to avoid adverse effects, drug-drug interactions, overdosing and in the presence of co-morbidities. An emphasis on safe storage of takeaway methadone is also needed. [George P, Vicknasingam B, Thurairajasingam S, Ramasamy P, Mohd Yusof H, Yasin MABM, Shah ZUBS. Methadone complications amongst opioid-dependent patients in Malaysia: A case series. Drug Alcohol Rev 2018;37:147-151].