[Changes in creatine kinase activity in serum following intramuscular injection]

The effect of intramuscular injections of two multivitamin preparations, two excipient preparations without vitamins, and a placebo preparation (glycine 2.5%) on serum creatine kinase activity (S-CK) in ten healthy volunteers (three female, seven male) aged between 23 and 25 years was investigated. One of the multivitamin preparations contained no lidocaine, the other 1% lidocaine. The one excipient formulation was isoosmotic, while the other contained added saline to bring it to the same degree of hyperosomolarity as the multivitamin formulation without lidocaine. The formulations were administered by deep ventrogluteal injection by means of a standardized injection technique. Blood samples were taken before and 6, 12, 24 and 48 h after injection. Following the administration of all the formulations except that of the glycine 2.5%, a marked increase in S-CK activity (1260 I.U./l) was observed 12 h after injection (normal range: male: 47-243 I.U./l, female: 39-226 I.U./l). The relative standard deviation for the 12 h S-CK value was 66.4-97.3%. On applying a threeway analysis of variance to the parameter S-CKmax, no significant differences (alpha = 5%) were found between the effects of the multivitamin and excipient formulations. There was a difference between these and glycine 2.5%, however. There were significant differences between individual volunteers but no significant differences based on the sequence in which the injections were given. With regard to the parameter S-CK AUC (area under the curve, trapezoidal rule), a significant difference (alpha = 5%) was observed only between glycine 2.5% and the multivitamin formulation containing 1% lidocaine.(ABSTRACT TRUNCATED AT 250 WORDS)