Experimental study on intraventricular and intrathecal administration of antibiotics (author's transl)

Abstract

Investigations was performed on effective and safe methods of the intraventricular and intrathecal administration of antibiotics. When antibiotics are administered intrathecally or intraventricularly, the main side effects are brainstem symptoms such as clouding of the consciousness, respiratory and circulatory disorders, and decerebration. In order to investigate the relation between the appearance of these brainstem symptoms and the concentration of the antibiotics in the basal cistern, different concentrations of various antibiotics including sulbenicillin (SBPC), gentamicin (GM) and cephaloridin (CER) were injected into the cisterna magna of rabbits and the respiratory rate, blood pressure, pulse rate, electroencephalograms, neurological findings and histological findings in the brain were observed. Five of six rabbits to which SBPC was injected into the cisterna magna showed tonic convulsions. The lowest concentration of SBPC injected among the five rabbits was 1, 500 mcg/ml. There was noted nystagmus, dilated pupil or upward conjugate deviation together with the tonic convulsions. Among the three rabbits to which CER was given, one was found to have a conjugate deviation and tremor at concentrations of 3, 000 mcg/ml or more. However, there were no neurological changes in the three rabbits to which GM was given, even at concentrations of 50, 000 mcg/ml. In all of the cases with neurological changes, there were noted increased blood pressure and changes in the electroencephalograms, but there were no fixed trends for the respiratory and pulse rates. Among 24 rabbits to which was given various antibiotics of 50-800 mcg/ml in concentration in the cisterna magna for seven consecutive days, there were histological changes in the seven rabbits. These changes consisted of congestion of the choroid plexus in seven, subarachnoidal hemorrhages in three and localized meningial thickening in four. The conclusion in regard to the safe dosage when administering antibiotics in the c.s.f. cavity is 50 mg or less for CER, CET and SBPC, and 12 mg or less for GM.