Background and Objective Oral tramadol, an atypical opioid approved in the United States (US) since 1995 and a Schedule IV controlled substance, has less abuse liability compared to Schedule II conventional opioids. Intravenous (IV) tramadol is not available in the US, but has the potential to fill a gap between non-opioid medications and conventional opioids for treatment of acute pain. This study evaluates IV tramadol in the management of postoperative pain compared to placebo and standard-of-care active control. Methods A phase 3, multicenter, double-blind, three-arm, randomized, placebo-and active-controlled, multiple-dose, parallel-group study was conducted to evaluate the efficacy and safety of 50 mg IV tramadol versus placebo and 4 mg IV morphine over 48 h in patients with postoperative pain following abdominoplasty surgery. Results IV tramadol was statistically superior (p < 0.05) to placebo and comparable to IV morphine for the primary and all key secondary efficacy outcomes and demonstrated numerically lower rates for the incidence of most common treatmentemergent adverse events (TEAEs) compared to morphine. No unexpected findings were observed for TEAEs, laboratory tests, vital signs, or electrocardiograms (ECGs). Over 90% of patients completed the study. Conclusion The study demonstrated that IV tramadol 50 mg is highly effective in the management of postoperative pain following abdominoplasty. The consistency of effects between tramadol and morphine (as compared to placebo) for primary and key secondary endpoints validates the efficacy of tramadol observed. The study also provided direct evidence of improved tolerability of IV tramadol over a standard-of-care conventional Schedule II opioid. IV tramadol may become a useful option in patients where exposure to conventional opioids is not desired.

IntroductionSurgical site infiltration with bupivacaine hydrochloride (HCl) is a standard element of postoperative analgesia for soft tissue surgeries, but results in short-lived analgesia. A novel bupivacaine implant, XARACOLL (bupivacaine HCl), is Food and Drug Administration approved for treatment of acute postsurgical pain following adult inguinal herniorrhaphy. This study examined the efficacy and safety of the bupivacaine implant (300 mg) compared with placebo for postsurgical pain after abdominoplasty.MethodsIn this double-blind, placebo-controlled study, patients undergoing abdominoplasty were randomized to three 100 mg bupivacaine implants or three placebo collagen implants, in a 1:1 ratio, implanted intraoperatively. No other analgesics were administered into the surgical site. Patients were allowed opioids and acetaminophen for postoperative pain. Patients were followed for up to 30 days after treatment. Primary outcome: the analgesic effect of the bupivacaine implants through 24 hours postsurgery, measured by the sum of time-weighted pain intensity (SPI24). Prespecified key secondary outcomes included SPI48 and SPI72, percentage of opioid-free patients through 24, 48, and 72 hours, and adverse events, which were tested sequentially to control for multiplicity (ie, if the first variable failed to reach significance, no subsequent variables were declared statistically significant).ResultsThe bupivacaine implant patients (n=181) reported statistically significant lower SPI24 (mean (SD) SPI24=102 (43), 95% CI 95 to 109) compared with placebo patients (n=184; SPI24=117 (45), 95% CI 111 to 123, p=0.002). SPI48 was 190 (88, 95% CI 177 to 204) for INL-001 and 206 (96, 95% CI 192 to 219) for placebo, and not significantly different between groups. The subsequent secondary variables were therefore declared not statistically significant. SPI72 was 265 (131, 95% CI 244 to 285) for INL-001 and 281 (146, 95% CI 261 to 301) for placebo. The opioid-free percentage of patients at 24, 48, and 72 hours was 19%, 17%, and 17% for INL-001 and 6.5% for placebo patients (at all timepoints). The only adverse event occurring in ≥5% of patients and for which proportion INL-001 >placebo was back pain (7.7% vs 7.6%).ConclusionThe study design was limited by not containing an active comparator. Compared with placebo, INL-001 provides postoperative analgesia that is temporally aligned with the period of maximal postsurgical pain in abdominoplasty and offers a favorable safety profile.Trial registration numberNCT04785625.