Subacute toxicity and recovery tests of Mequitazine, a new phenothiazine type anti-histamine agent, were carried out using each 20 male and female dogs. The drugs was administered orally in doses of 0, 1, 5 and 25 mg/kg day for 14 weeks. Recovery test was carried out for following 4 weeks. As a result, transient decrease of the body weights and somnolences were observed in both male and female dogs given 25 mg/kg. In a female dog given 25 mg/kg, extrapyramidal reaction accompained with tremors and muscle stiffenings was observed. But no dead animals were observed throughout experimental period. Vomitings, mydriasis and loss of appetite were observed with the dose-responsiveness, but these symptoms were reduced after 1-2 weeks administration. No abnormal changes were observed in hematological, serum biochemical, and other examinations. In histopathological examinations, slights changes were observed in liver, kidneys, mesenteric lymph nodes, palpebra and conjunctival membrane. But these changes were reversible in recovery period. From these results, it was suggested that the maximum non-effective and maximum safety dises were 1 mg/kg/day and 5 mg/kg/day, respectively.
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