CHRONOTOXICOLOGY OF FLORFENICOL

• Published in: Chronobiology international Vol. 18; no. 3; pp. 567 - 572
• Main Authors: Picco, E. J., Díaz, D. C., Valtorta, S. E., Boggio, J. C.
• Format: Journal Article
• Language: English
• Published: Monticello, NY Informa UK Ltd 01.01.2001; Taylor & Francis; Dekker
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Chronotoxicity; Circadian Rhythm; Circadian rhythms; Dose-Response Relationship, Drug; Drug Overdose; florfenicol; Florfenicol toxicity; Homozygote; Light; Male; Medical sciences; Mice; Pharmacology. Drug treatments; Rodents; Thiamphenicol - analogs & derivatives; Thiamphenicol - pharmacology; Time Factors; Toxicity; Rodentia; Daily variation; Biological rhythm; Circadian rhythm; Vertebrata; Antibiotic; Mammalia; Lethal dose 50; Chronobiology; Mouse; Animal; Florfenicol; Antibacterial agent
• ISSN: 0742-0528; 1525-6073
• DOI: 10.1081/CBI-100103977

Sixty 3-month-old homozygote male mice were studied for circadian rhythmicity in the toxicity of florfenicol overdose. Animals were kept under a regimen of 12h light, 12h darkness (12:12 LD) with food and water available ad libitum. The LD50 (median lethal) dose was determined in a preliminary experiment and was administered to groups of 10 mice at six different clock times (hours) after light onset (HALO): 0, 4, 8, 12, 16, and 20 HALO. Cosinor analysis verified a statistically significant (P <. 04) circadian rhythm in the toxic effect (mortality) of florfenicol. Mortality was greatest when the drug was injected 4h after the commencement of the activity span (16 HALO) and least when injected 4h after the start of the diurnal rest span (4 HALO). Mortality was 2.5 times greater when drug injection was given at 16 HALO than at 4 HALO. (Chronobiology International, 18(3), 567-572, 2001)