Methadone drug interactions

As with any other medication prescribing there must be awareness of drug interactions, with important ones for methadone relating to antivirals, psychotropics, anticonvulsants and antibiotics. 

Davis MP, Walsh D Methadone for relief of cancer pain A review of pharmacokinetics, pharmacodynamics, drug interactions and protocols of administration. Support Care Cancer 2001 9 73. [PMID 11305074]... 

Contraindications to interferon alfa therapy include hepatic decompensation, autoimmune disease, and history of cardiac arrhythmia. Caution is advised in the setting of psychiatric disease, epilepsy, thyroid disease, ischemic cardiac disease, severe renal insufficiency, and cytopenia. Alfa interferons are abortifacient in primates and should not be administered in pregnancy. Potential drug-drug interactions include increased theophylline levels and increased methadone levels. Co-administration with didanosine is not recommended because of a risk of hepatic failure, and co-administration with zidovudine may exacerbate cytopenias. 

Tarumi Y, Pereira J, Watanabe S. Methadone and fluconazole respiratory depression by drug interaction. J Pain Symptom Manage 2002 23(2) 148-53. 

In vitro inhibition of CYP2D6 activity by methadone (K = 3 M) predicted drug interactions in vivo. This finding was confirmed in 42 abusers of oral opiates undergoing treatment with methadone (Wu et al. 1993a). 

DeMaria PA, Serota RD. A therq>eutic use of the methadone fluvoxamine drug interaction. JAMctDis( 9 ) 18, 5-12. 

Drug-drug interactions Cannabis Cannabis is commonly used by individuals taking methadone maintenance treatment. In a study of the effects of cannabis on methadone pharmacokinetics in 151 patients taking methadone maintenance, cannabis use and higher methadone doses were associated with a lower trough methadone concentration, believed to reflect rapid methadone clearance [122 ]. 

Lemesle F, Lemesle F, Nicola W, Pierre Jonville-Bera A. First case of stress cardiomyopathy as a result of methadone withdrawal secondary to drug-drug interaction. Am J Emerg Med 2010 28 387. e5-6. 

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