Drug interactions between opioids and antiretroviral medications: interaction between methadone, LAAM, and delavirdine
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Study Design
The authors report the results of a clinical pharmacology study designed to determine whether significant pharmacokinetic and/or pharmacodynamic interactions occur between the non‐nucleoside reverse transcriptase inhibitor, delavirdine (DLV), and either methadone or levoalpha acetyl methadol (LAAM) (n = 40).
Study Results
DLV significantly decreased methadone clearance (p = .018) and increased the methadone elimination half‐life (p < .001) with a resultant increase in AUC of 19% and Cminof 29%. The combined effect of DLV on the total concentration of LAAM and its active metabolites, nor LAAM and dinor LAAM, was to significantly increase AUC by 43% (p < .001), Cmax by 30% (p = .013), and Cmin by 59% (p = .004) while decreasing Tmax (p = .05). Cognitive deficits over the seven‐day study period as measured by the Mini‐Mental State Examination, opioid withdrawal symptoms as measured by the Objective Opioid Withdrawal Scale, or complaints of adverse symptoms were not observed. Methadone and LAAM did not affect DLV concentrations.
Study Conclusions
The findings from this study show that DLV treatment in methadone‐ or LAAM‐maintained individuals results in altered opioid pharmacokinetics with an increased exposure and potential risk for opioid toxicity with methadone or LAAM treatment and an increased risk of cardiac toxicity with concomitant LAAM and DLV administration.
References
McCance-Katz EF, Smith PM, Rainey PM, Morse GD, Friedland G, Boyarsky B, Jatlow P. Drug interactions between opioids and antiretroviral medications: interaction between methadone, laam, and delavirdine. American Journal On Addictions. 2006; 1: 23-34.
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