Undesired side effects of tapentadol in comparison to oxycodone. A meta-analysis of randomized controlled comparative studies]

Tapentadol is a new centrally acting analgesic with a dual mode of action as an agonist of the A mu-opioid receptor and as a norepinephrine reuptake inhibitor. The aim of the present study was to evaluate the results from randomized controlled trials investigating the relative amount of adverse effects using tapentadol or oxycodone for the treatment of pain. A quantitative systematic review was carried out according to the PRISMA recommendations on randomized controlled trials comparing tapentadol and oxycodone in pain treatment. The incidences of typical adverse side effects of opioid-based analgesic therapy (e.g. nausea, vomiting, obstipation or pruritus) were extracted and the pooled relative risks (RR) with corresponding 95% confidence intervals (CI) were calculated. A total of 9 trials involving 7,948 patients were included and of these 2,810 patients were treated with oxycodone and 5,138 were treated with tapentadol in equivalent analgesic dosages as documented by an equivalent analgesic effect. The risk of typical opioid-based adverse effects, such as nausea (RR 0.61; 95% CI 0.57-0.66), vomiting (RR 0.50, 95% CI: 0.41-0.60), obstipation (RR 0.47, 95%-CI 0.40-0.56), dizziness (RR 0.86, 95% CI 0.78-0.95), somnolence (RR 0.76, 95% CI 0.67-0.86) and pruritus (RR 0.46, 95% CI 0.37-0.58) was reduced when tapentadol was used for analgesic treatment. These adverse effects were investigated in all nine trials. The risk for dryness of the mouth (6 trials, 6,218 patients, RR 1.79, 95% CI 1.40-2.29) and dyspepsia (1 trial, 646 patients, RR 2.75, 95% CI 1.09-6.94) was increased when tapentadol was used instead of oxycodone. There were no significant differences in the relative risk for any other investigated adverse effect such as dysentery, headache or fatigue. The results show that using tapentadol significantly reduces the risk of the typical opioid-based adverse effects compared with oxycodone while providing equivalent analgesic treatment.