Investigation of bioequivalence and tolerability of intramuscular ceftriaxone injections by using 1% lidocaine, buffered lidocaine, and sterile water diluents

The pharmacokinetics and tolerability of 1-g doses of ceftriaxone diluted in sterile water, 1% lidocaine, or buffered lidocaine were investigated. No difference in bioequivalence was noted between the three treatments. No difference in peak creatine kinase values was seen. By use of a quantitative pain scale, injection of ceftriaxone with the water diluent was significantly more painful than that with either of the other two diluents. No difference in injection pain was noted for lidocaine or buffered lidocaine.