Abstract: Objective To compare the efficacy and side effect between Paracetamol and Tramadol Hydrochloride Tablet and Paracetamol and Dihydrocodeine Tartrate Tablet on chronic pain. Methods From October, 2013 to October, 2015, 84 patients with chronic pain were divided into group A (n=42) and group B (n=42), who took two Tramadol tablets or Dihydrocodeine Tartrate tablets, three times a day orally for five days. They were assessed with Numerical Rating Scale (NRS), and the incidence of satisfaction and side effect were investigated. Results The score of NRS decreased in both groups after treatment (t>9.402, P<0.001), and there was no significantly difference between them (t=0.461, P=0.941). No significant difference was observed in incidence of pain relief and satisfaction between two groups (χ2=0.979, P=0.323). The incidence of constipation (χ2=5.864, P=0.006) and abdominal distention (χ2=9.946, P=0.002) were less in group A than in group B, but the incidence of nausea was more (χ2=4.934, P=0.026), while the incidence of dizziness, vomiting and tiredness was no significantly different between two groups (χ2<1.451, P>0.061). Conclusion The analgesic efficacy is similar of both drugs, but different in side effects of gastrointestine.

Key words: chronic pain, Tramadol, Dihydrocodeine, analgesia, side effect