Psychosomatics
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Earlier reviews have covered pharmacokinetic drug interactions of natural and semi-synthetic opioid analgesics. This review will focus on the pharmacokinetic drug-drug interactions of methadone, propoxyphene, levomethadyl, meperidine, other phenylpiperidines (such as fentanyl), pentazocine, diphenoxylate, loperimide, and tramadol. ⋯ Therefore, these drugs are likely to produce drug-drug interactions when the CYP3A4 system is inhibited or induced. Knowledge of these drug-drug interactions is important because such interactions may decrease drug efficacy or result in adverse effects.