The effects of cytochrome P450 2D6 inhibitors on a high-dose tramadol taper for medically supervised opioid withdrawal: a retrospective chart review.

Background: Tramadol is used off-label for medically supervised opioid withdrawal. Tramadol is metabolized by CYP2D6 to an active metabolite with significantly more pharmacologic activity compared to the parent compound. Objectives: The objective of this study is to evaluate the effects of CYP2D6 inhibitors on patient response to a tramadol taper for medically supervised opioid withdrawal. Methods: A retrospective chart review of patients who received a tramadol taper for medically supervised opioid withdrawal was conducted comparing patients who received concomitant moderate-to-strong CYP2D6 inhibitors to patients without concomitant therapy. The primary outcome was the change in Clinical Institute Narcotic Assessment (CINA) scores from baseline to discharge. Secondary outcomes included area under the curve of CINA scores over time, additional CINA outcomes, length of stay, and readmissions. Results: Of 100 charts reviewed, 30 patients received a concomitant moderate-to-strong CYP2D6 inhibitor. There were no statistically significant differences between the baseline demographics of the two groups. Change from baseline CINA to discharge did not differ significantly between the Non-2D6 group and the 2D6 group (-4.0 ± 3.83 and -4.5 ± 4.48 respectively; p = 0.606). The average CINA score for nausea and vomiting was significantly higher in the Non-2D6 group compared to the 2D6 group (0.34 ± 0.35 and 0.18 ± 0.33 respectively; p = 0.019). Otherwise there were no significant differences found in any secondary outcomes. Conclusions: Based on these results, moderate-to-strong CYP2D6 inhibitors do not appear to have a significant impact on the withdrawal course for patients treated with a high-dose tramadol taper.