Absorption of effervescent paracetamol tablets relative to ordinary paracetamol tablets in healthy volunteers

The aim of this study was to compare the rate of absorption between ordinary paracetamol tablets and effervescent paracetamol tablets.

Twenty healthy volunteers participated in an open randomised crossover study and were given a 1000-mg dose of either ordinary paracetamol tablets (2 x 500 mg Panodil tablets, SmithKline Beecham) or effervescent paracetamol tablets (2 x 500 mg Pinex Brusetablett, Alpharma AS) with a 3-week washout period in between. Blood samples were collected for 3 h. Maximum serum concentration (Cmax) and the time to maximum serum concentration (tmax) were recorded and the area under the concentration versus time curve (AUC) was calculated.

The mean tmax was significantly shorter when paracetamol effervescent tablets were taken (27 min) rather than ordinary paracetamol tablets (45 min) (P = 0.004). There was no significant difference between the mean Cmax of 143 micromol/l with effervescent tablets and that of 131 micromol/l with ordinary tablets. The mean AUC(0-3 h) was significantly higher with paracetamol effervescent tablets (223.8 micromol x h x l(-1)) than with ordinary tablets (198.2 micromol x h x l(-1); P = 0.003). After 15 min, 17 (85%) subjects in the effervescent group had a serum concentration of 70 micromol/l (lower therapeutic serum concentration) or higher relative to only 2 (10%) subjects in the ordinary tablet group (P = 0.001).

Paracetamol effervescent tablets are absorbed significantly faster than ordinary paracetamol. Thus, effervescent tablets might offer significantly faster pain relief when paracetamol is used.