Palexia (tapentadol): Novel opioid analgesic

Tapentadol (Palexia) is a new analgesic available as standard-release tablets for moderate to severe acute pain and as prolonged-release tablets for severe chronic pain.

Two formulations of Palexia for pain relief
Two formulations of Palexia for pain relief


Palexia (tapentadol) is a centrally acting analgesic with a dual mechanism of action as both a μ-opioid receptor agonist and a noradrenaline reuptake inhibitor. Maximum serum concentrations are typically observed around 1.25 hours after administration of the standard-release preparation and 3–6 hours after administration of the sustained-release preparation.1,2


A pooled analysis of data from 3 double-blind phase III safety and efficacy studies compared sustained-release tapentadol with oxycodone and placebo in patients with chronic low back pain or osteoarthritis pain. Following a 3-week titration period, patients were randomised to receive either twice-daily doses of sustained-release tapentadol 100–250mg, sustained-release oxycodone hydrochloride 20–50mg or placebo for a 12-week maintenance period. In the efficacy analysis (n=2968), tapentadol produced significantly greater reductions in pain intensity from baseline than placebo, when assessed both at week 12 and over the whole maintenance period (p<0.001 for both). For both of these endpoints, the efficacy of tapentadol was non-inferior to that of oxycodone (p<0.001). In the safety analysis (n=2974), tapentadol had superior gastrointestinal tolerability to oxycodone (p<0.001) and fewer patients discontinued tapentadol than oxycodone (43.5% vs 61.7%).3

The long-term safety and tolerability of sustained-release tapentadol was assessed in a randomised open-label phase III trial. Patients with chronic low back pain or osteoarthritis pain (n=1117) received twice-daily doses of 100–250mg tapentadol or 20–50mg sustained-release oxycodone hydrochloride for up to 1 year. Treatment-emergent adverse events occurred in 85.7% of the tapentadol group and 90.6% of the oxycodone group, with 22.1% and 36.8% of patients in each group, respectively, discontinuing treatment as a result.4

A phase III study evaluated the efficacy and tolerability of immediate-release tapentadol for moderate to severe acute pain following orthopaedic surgery. Patients (n=901) were randomised to receive either 50mg or 75mg tapentadol, 10mg immediate-release oxycodone hydrochloride or placebo every 4–6 hours for 72 hours after bunionectomy. The mean sum of pain intensity differences (SPID) between baseline and the first 48 hours of treatment was significantly higher for tapentadol than for placebo (p<0.001 for both doses) and both doses of tapentadol showed non-inferior efficacy to oxycodone. Nausea and vomiting were significantly less common with tapentadol 50mg than with oxycodone (p<0.001).5

Immediate-release tapentadol was also found to be non-inferior to immediate-release oxycodone in patients with uncontrolled osteoarthritis pain awaiting joint replacement surgery. In a randomised, double-blind phase III trial, 666 patients received either 50mg or 75mg tapentadol, 10mg oxycodone hydrochloride or placebo every 4–6 hours during waking hours for 10 days. The SPID between baseline and day 5 was significantly lower in patients receiving tapentadol 50mg or 75mg than in those on placebo (p<0.001). The incidence of nausea, vomiting and constipation was significantly lower for both tapentadol doses than for oxycodone (nominal p<0.001).6


  1. Palexia Summary of Product Characteristics, February 2011.
  2. Palexia SR Summary of Product Characteristics, February 2011.
  3. Lange B et al. Adv Ther 2010; 27: 381–99.
  4. Wild J et al. Pain Pract 2010; 10: 416–27.
  5. Daniels S et al. Curr Med Res Opin 2009; 25: 1551–61.  
  6. Hartrick C et al. Clin Ther 2009; 31: 260–71.

View Palexia drug record

Further information: Grunenthal

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