BASIC AND CLINICAL STUDIES ON DOXYCYCLINE

Abstract

It is well known that the tetracycline (TC) and TC-derivatives accumulate in the mineralizing bone tissue. This effect has been utilized as TC labelling of the osseous tissue. However, this may cause the disagreeable yellow pigmentation of the bone and teeth after administrating clinically the antibiotics. Doxycycline offered from Pfizer Taito Co., is a new tetracycline derivative. In the present study, we examined experimentally the binding of doxycycline to bone, and studied clinically the effect of the drug in the infectious diseases of bone and joint. Less staining ability was confirmed in young rats administered intra peritoneally doxycycline than those receiving an equivalent dosage of oxytetracycline and demethylchlortetracycline. To check if there might be the difference also in vitro, af ter shaking each TC with tribasic calcium phosphate and the human cortical bone powder, the residual supernatant TC and the adsorbed TC in precipitate were measured by ultraviolet resorption at 380-370 mg and fluorometry at 510 mp. The percentage of TC fixed to calcium phosphate and the powdered bone were lower in doxycycline than others. Clinical use: Our cases administered doxycycline were 17; subacute or chronic pyogenic osteomyelitis 5, secondary osteomyelitis after open fracture 4, purulent arthritis 2, and the infection of the soft tissue 6. All p atients were administered orally 200 mg of the drug on the first day, followed by 100 mg daily, and some were given the combined surgical treatment. It is concluded from our results that doxycy cline is a satisfactory effective antibiotic to the infectious bone and joint diseases, moreover that it may be safe TC-derivative in a viewpoint of less staining of bone and teeth.