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Updated: Jan 6, 2026

Intracranial Pharmacotherapy and Pain Assays in Rodents
Published on: April 9, 2019
A Multicenter, Randomized, Open-Label, Active-Controlled, Parallel-Group Study Evaluating the Pharmacokinetics of
Zhiqin Hu1, Tenghua Wang1, Xiaoqiang Li2
1Phase I Clinical Research Center, Guangdong Engineering Research Center of Early Clinical Trials of Biotechnology Drugs, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
Background And Objectives:
Tapentadol is a novel, centrally acting, potent analgesic with a dual mechanism of action on µ-opioid receptors and noradrenaline reuptake in the central nervous system. This study was conducted to compare the pharmacokinetics, preliminary pharmacodynamics, and safety of single-dose tapentadol hydrochloride intravenous infusion (IV) with tapentadol hydrochloride oral immediate-release (IR) and tapentadol hydrochloride oral extended-release (ER).
Methods:
In this randomized, open-label, multicenter, active-controlled, parallel-group phase 1 trial, 28 Chinese patients with moderate noncancer pain were randomly assigned in a 1:1:1 ratio to receive a single dose of either tapentadol IV (0.5 mg/kg), tapentadol IR (100 mg), or tapentadol ER (100 mg). Adverse events were monitored, serum samples were collected for pharmacokinetic analysis, and 11-point numeric rating scale (NRS) scores were recorded for preliminary pharmacodynamic evaluation during the study.
Results:
The geometric mean (geomean) absolute bioavailability of tapentadol IR and ER after a single-dose administration under fasting conditions was 44.3% (90% confidence interval [CI] 37.5-52.3) and 34.0% (90% CI 27.1-52.3), respectively. The NRS scores demonstrated a decreasing trend across all three groups. Treatment-related adverse event (TRAE) occurred in 50.0% (tapentadol IV), 70% (tapentadol IR), and 50.0% (tapentadol ER) of patients. No events led to dose adjustment or interruption or necessitated additional concomitant medication, and there were no serious adverse events (SAEs), withdrawals, or deaths.
Conclusions:
Tapentadol IV exhibits precise pharmacokinetics, promising pharmacodynamic properties, and a favorable safety profile compared with IR and ER routes for patients with moderate noncancer pain, supporting further clinical research and development of tapentadol injection.
Trial Registration:
http://www.chinadrugtrials.org.cn/ ; CTR20212327 2021-09-27.
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