In vitro and in vivo antimicrobial action of fluphenazine.

The antipsychotic drug fluphenazine was obtained in a dry powder form and was screened with respect to 482 strains of bacteria, which included 170 Gram-positive and 326 Gram-negative strains. Nutrient agar plates containing increasing concentrations of fluphenazine (0-200 micrograms/ml) were used for the determination of the minimum inhibitory concentration (MIC) which was demonstrated by inoculating a loopful of an overnight peptone water culture of the organism on nutrient agar plates and determining the MIC against a control. Fluphenazine was detected to possess pronounced action against both Gram-positive and Gram-negative bacteria at 20-100 micrograms/ml. In the in vivo studies it was seen that when fluphenazine was used at a concentration of 1.5 micrograms/g and 3 micrograms/g mouse body weight both the levels offered significant protection to Swiss strain of white mice when challenged with 50 minimum lethal dose (MLD) of a virulent strain of Salmonella typhimurium 74. The in vivo data with fluphenazine were highly significant (p < 0.001) according to the chi-square test.