Multiple organ toxicity, including hypochromic anemia, following repeated dose oral administration of phenobarbital (PB) in rats.
A 4-week repeated dose oral toxicity study of phenobarbital (PB) sodium was conducted in F344 rats of both sexes at PB doses of 0.8, 8, and 80 mg/kg/day to fully elucidate its general toxicity including hematological changes. Both sexes in the 80 mg/kg/day group showed staggering gait, lacrimation, and/or sedation, which were more evident in the early stage of treatment. The body weight gain and food consumption were greater in these animals than in controls. Hematology revealed a significant reduction in the hematocrit (Ht), hemoglobin concentration (Hb), and erythrocyte count (RBC) in both sexes at 80 mg/kg/day, which was accompanied by a decrease in the cell mean Hb (CHCM) in mature erythrocytes with an increase in unsaturated iron binding capacity. Female rats also showed reduction in the CHCM in reticulocytes, content of hemoglobin per reticulocyte, and transferrin saturation. PB prolonged the activated partial thromboplastin time and inversely increased the platelet count with no evidence of platelet activation. Well-known toxic effects of PB on the liver and thyroid were observed in a dose-dependent manner, along with altered lipid, glucose, and electrolyte metabolism. The serum levels of PB increased dose-dependently, when examined in females received 8 and 80 mg/kg/day on day 1 and 28; there were no difference in C(max) and AUC(0-24) values between day 1 and day 28. These results indicated that PB has the potential to elicit multiple organ toxicity including an effect on the hematopoietic system. The hematological analysis provided evidence for hypochromic anemia, plausibly caused by the impairment of iron utility.
Kojima
Sayuri
S
The Institute of Environmental Toxicology, Joso-shi, Ibaraki, Japan. kojima@iet.or.jp
Sasaki
Junya
J
Tomita
Mariko
M
Saka
Machiko
M
Ishizuka
Katsumi
K
Kawakatsu
Hisao
H
Yoshida
Toshinori
T
Kosaka
Tadashi
T
Enomoto
Akiko
A
Nakashima
Nobuaki
N
Harada
Takanori
T
D000284:Administration, Oral; D000747:Anemia, Hypochromic / Q000139:chemically induced*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005260:Female; D005684:Gait / Q000187:drug effects; D007501:Iron / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D018675:Toxicity Tests; D016482:Urinalysis
D007501:Iron; D010634:Phenobarbital