Nonsteroidal anti-inflammatory drugs causing local inflammation of tissue at the site of injection

Injections of drug solutions can be followed by the development of local complications such as phlebitis, cellulitis, phlegmon, and necrosis. The development of these complications is not precluded by medical personnel’s observing precisely the rules of aseptics and antisepsis as well as the instructions on applying drug solutions for injections. In this case, development of inflammation can be caused by the local irritant action of a solution due to high concentration of active drug substance. In a number of studies, it was found that irritant action on tissues can be characteristic of solutions not only with high (over 10%) but also with low indices of the concentration of active drug substance, for example, nonsteroidal anti-inflammatory drugs (NSAIDs). We suggested that irritant action of the latter could be caused by the high total concentration of active drug substance and adjuvants which render the solution high osmolality. As local inflammation in warm-blooded mammals is accompanied by local hyperthermia, the study of changes in local skin temperature at the site of injections of NSAIDs solutions can assist in preclinical evaluation of their local safety in vivo. Hence, we aimed to investigate changes in pigs local skin temperature at the site of intramuscular (IM) injections of NSAIDs solutions with different osmolality.