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Background: This is the first study to compare plasma and cerebrospinal fluid (CSF) pharmacokinetics of intravenous (IV), oral (PO), or rectal (PR) formulations of acetaminophen. Methods: Healthy male subjects (N = 6) were randomized to receive a single dose of IV (OFIRMEV Ò ; Cadence) 1,000 mg (15 minute infusion), PO (2 Tylenol Ò 500 mg caplets; McNeil Consumer Healthcare), or PR acetaminophen (2 Feverall Ò 650 mg suppositories; Actavis) with a 1-day washout period between doses. The 1,300 mg PR concentrations were standardized to 1,000 mg. Acetaminophen plasma and CSF levels were obtained at T0, 0.25, 0.5, 0.75, 1, 2, 3, 4, and 6 hours.Results: IV acetaminophen showed earlier and higher plasma and CSF levels compared with PO or PR administration. CSF bioavailability over 6 hours (AUC 0-6 ) for IV, PO, and PR 1 g was 24.9, 14.2, and 10.3 lgAEh/mL, respectively. No treatment-related adverse events were reported. One subject was replaced because of premature failure of his lumbar spinal catheter. The mean CSF level in the IV group was similar to plasma from 3 to 4 hours and higher from 4 hours on. Absorption phase, variability in plasma, and CSF were greater in PO and PR groups than variability with IV administration.Conclusions: These results demonstrate that earlier and greater CSF penetration occurs as a result of the earlier and higher plasma peak with IV administration compared with PO or PR. n

& AbstractObjectives: The clinical utility of conventional IV opioids is limited by the occurrence of opioid-related adverse events. Oliceridine is a novel G protein-biased l-opioid receptor agonist designed to provide analgesia with an improved safety and tolerability profile. This phase III, double-blind, randomized trial (APOLLO-2 [NCT02820324]) evaluated the efficacy and safety of oliceridine for acute pain following abdominoplasty. Methods: Patients received a loading dose of either placebo, oliceridine (1.5 mg), or morphine (4 mg), followed by demand doses via patient-controlled analgesia (0.1, 0.35, or 0.5 mg oliceridine; 1 mg morphine; or placebo) with a 6minute lockout interval. The primary endpoint was the proportion of treatment responders over 24 hours for oliceridine regimens compared to placebo. Secondary outcomes included a predefined composite measure of respiratory safety burden (RSB, representing the cumulative duration of respiratory safety events) and the proportion of treatment responders vs. morphine. Results: A total of 401 patients were treated with study medication. Effective analgesia was observed for all oliceridine regimens, with responder rates of 61.0%, 76.3%, and 70.0% for the 0.1-, 0.35-, and 0.5-mg regimens, respectively, compared with 45.7% for placebo (all P < 0.05) and 78.3% for morphine. Oliceridine 0.35-and 0.5-mg demand dose regimens were equi-analgesic to morphine using a noninferiority analysis. RSB showed a dose-dependent increase across oliceridine regimens (mean hours [standard deviation],

Purpose: Oliceridine is a novel G protein-biased µ-opioid receptor agonist designed to provide intravenous (IV) analgesia with a lower risk of opioid-related adverse events (ORAEs) than conventional opioids. Patients and methods: APOLLO-1 (NCT02815709) was a phase III, double-blind, randomized trial in patients with moderate-to-severe pain following bunionectomy. Patients received a loading dose of either placebo, oliceridine (1.5 mg), or morphine (4 mg), followed by demand doses via patient-controlled analgesia (0.1, 0.35, or 0.5 mg oliceridine, 1 mg morphine, or placebo). The primary endpoint compared the proportion of treatment responders through 48 hours for oliceridine regimens and placebo. Secondary outcomes included a composite measure of respiratory safety burden (RSB, representing the cumulative duration of respiratory safety events) and the proportion of treatment responders vs morphine. Results: Effective analgesia was observed for all oliceridine regimens, with responder rates of 50%, 62%, and 65.8% in the 0.1 mg, 0.35 mg, and 0.5 mg regimens, respectively (all P<0.0001 vs placebo [15.2%]; 0.35 mg and 0.5 mg non-inferior to morphine). RSB showed a dose-dependent increase across oliceridine regimens (mean hours [