[Comparative trial of lysine acetylsalicylate and paracetamol on pain in daily medical practice]

Abstract

We performed a randomized double-blind controlled study in community medical practice comparing lysine acetylsalicylate (LAS) and paracetamol (PAR). Both drugs were given at the same dose (1 g, thrice daily) during two days; from the third to the seventh day, the patients could freely take the same drug if necessary. The analgesic effect of drugs was measured by two means: an analog scale of pain during day 1 & 2 and the count of drugs units taken during days 3 to 7. The side effects were reported. We included 473 patients (167 men, 306 women) by means of a group of 54 general practitioners. 470 patients were stratified according to the site of pain: head (n = 113), joints (n = 80), back (n = 193), thorax (n = 11), teeth (n = 48), ENT (n = 25). The pain was either acute (73%) or chronic (27%) and scored an average +/- SD of 76 +/- 12 mm on an analog visual scale from 0 to 100 mm. Response was defined as a decrease of at least 50% of the pain score. Before intake of active drugs, all patients were given placebo. Only 14% responded. Under LAS or PAR, although the difference is not statistically significant, the number of responders was slightly higher with LAS than with PAR. Moreover, the study yields some interesting differences. During day 1 and day 2, the patients of the LAS group had less pain than those of the PAR group. This difference became statistically significant at D2 H12 (p < 0.05). LAS was significantly more effective than PAR in patients with back pain (p < 0.01), and there was a trend in favor of LAS in dental and ENT pain, and for intense pain. PAR never yielded better response levels than LAS. Among the placebo-unresponsive patients, the amount of drug taken from day 3 to day 7 was significantly lower in the LAS group than in the PAR group (p < 0.05). The side effects were comparable in both groups. According to the investigators' point of view both drugs were similarly well accepted by the patients (89.3% in LAS group, 94% in PAR group). The fact that LAS seems more effective than PAR in some kinds of pain is to bring near to the anti-inflammatory action of LAS and to its better bioavailability.