Fundamental and clinical studies on doxycycline (DOTC) in the field of pediatrics were performed and results were summarized as follows:
1) The MICs of DOTC against coagu lase-positive staphylococci isolated from acute respiratory tract infections, were lower than those of other tetracyclines (TC). But it was assumed that the highly resistant strains to other TC had also cross-resistance to DOTC, and the highly resistant strains were observed very frequently.
2) Single o ral dose of 5 and 2 mg/kg produced a maximum level of 8. 5 and 2. 3 mcg/ml on the average 2 hours later, respectively. The blood level after 24 hours was still maintained at the level of 0. 34 and 0. 2 mcg/ml, respectively. By the single oral administration of 2 mg/kg on the first day, followed by 1 mg/kg/day for three successive days, the accumulation of the drug was not observed on and after the next administration. The urinary recovery rate reached to about 30% within 24 hours.
3) The efficacy of DOTC for acute respiratory tract infections in the field of pediatrics, espe cially to mycoplasma infections has well been demonstrated. Its effect was as good as other TC and it was deemed that DOTC was not effective to the infections of highly resistant strains to other TC.
4) The administration of 5-10 mg/kg b. i. d. to children will easily cause the side effe ct as diarrhoea, and the dose should be decreased lower than this dose. Optimal dose was assumed to be between 1 and 2 mg/kg/day, while the study would be pursued furthermore. Disturbance of liver function by the administration of 5-10 mg/kg/day of DOTC has not been observed.
