Comparison of the analgesic efficacy of lysine acetylsalicylate and paracetamol in ENT pain: a randomized double-blind study in adults

OBJECTIVE: Unlike paracetamol, aspirin has anti-inflammatory properties whi ch may be helpful in relieving pain associated with inflammation. To confir m this hypothesis, we performed a randomized, double-blind, double-dummy st udy to compare the relative analgesic efficacy of lysine acetylsalicylate ( LAS) and paracetamol (PAR) in ENT pain in adults. PATIENTS AND METHODS: After initiation oi the treatment by a placebo (PCA), both drugs were given at the same dose (1 g twice daily on D1 and 1 g thre e times daily on D2) for two days. From the third day to the seventh day, t he patients could freely take the same drug ii necessary. The analgesic eff ect was assessed by measuring the area under the curve (AUC) of pain severi ty as scored by patients on a visual analogue scale. The secondary efficacy criteria were the difference relative to the basal pain score of the score s at each evaluation rime (PID), the sum of these differences (SPID), and t he proportion oi: patients responding to the treatment (i.e. experiencing a decrease of at least 50% in the pain score). RESULTS: A total of 312 patients, included by 30 French centres, were treat ed by LAS (n = 156) or PAR (n = 156). Pain was related to an infection in 9 8% oi the cases. Nine percent of patients in each treatment group were resp onders to the PLA and were consequently not included in the per protocol (P P) analysis but in the intent-to-treat (ITT) analysis. During days 1 and 2, patients in the LAS group had less pain than those of the PAR group, the d ifference becoming significant at Day 2 whatever the population analysed, P P (p = 0.01) or ITT (p = 0.01). LAS also showed better analgesic efficacy t han PAR as assessed by measures of PID and SPID, the difference being signi ficant at several times of evaluation for PID, and on Day 2 for SPID evalua tion in the PP (p = 0.01) and ITT analysis (p = 0.007). The proportion of r esponders was significantly higher in the LAS group than in the PAR group ( 70% Versus 56%, p = 0.01). Safety was comparable between the treatment grou ps. The overall efficacy judgement of investigators and patients was signif icantly better for LAS than for PAR (p = 0.01 and p = 0.006 respectively at the Day 2 evaluation). CONCLUSION: In this study, LAS proved to be more effective than PAR in the treatment of ENT-associated pain iii adults. This is probably related to th e anti-inflammatory activity of LAS.