METHOD: α-tocopherol monoester of MFA (TMMA) and α-tocopherol di-ester of MFA (TDMA) were synthesized by esterification reaction and were subjected to various in vivo characterizations.
RESULTS: Masking of the carboxylate group of MFA with the proposed pro-moieties significantly (p<0.05) delayed the onset of tonic-clonic seizure in mice. Besides, the intraperitoneal administration of TMMA and TDMA in mice produced significantly (p<0.05) stronger anti-inflammatory effects in the carrageenan-induced paw edema test and greater anti-nociceptive effect in the acetic acid-induced writhing test than MFA at an equimolar dose of 20 mg/kg. Treatment with TMMA and TDMA caused a significant (p<0.05) inhibition of pain at 1st and 2nd phases of formalin-induced licking test in mice, whereas treatment with MFA inhibited the 2nd phase only. Pretreatment with naloxone and flumazenil significantly (p<0.05) reversed the anti-nociceptive effect of MFA, TMMA and TDMA in the acetic acid-induced writhing test. In addition, treatment with TMMA and TDMA caused significantly (p<0.05) a higher inhibition of pain in the glutamate-induced licking response in mice than MFA.
CONCLUSION: Masking the carboxylate moiety of MFA by α-tocopherol and α-tocopherol acetate has a great potential for reducing CNS toxicity, enhancing the therapeutic efficacy and altering the mode of anti-nociceptive action.
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].