The protective and therapeutic effect of H1-antihistamine diphenhydramine was compared with the standard antidote
atropine on acute model of organophosphate insecticide dichlorvos poisoning in 7-14 days old chicks. The 24 h oral median
lethal dose (LD50) of dichlorvos was determined to be 15.2 mg/kg body weight in the chicks. Intramuscular (i.m.) injection of
diphenhydramine at 10 mg/kg 15 minutes before oral dichlorvos dosing increased the oral LD50 value to reach 26.2 mg/kg with
protection ratio of 72%. The oral dosing of dichlorvos at 18 mg/kg caused acute signs of poisoning which were salivation,
lacrimation, gasping, tremor, frequent defecation, recumbancy, convulsions and death in 100% of the chicks during the first 4
h of dosing. Diphenhydramine injection (10 mg/kg, i.m.) 15 minutes before or immediately after oral dichlorvos dosing (18
mg/kg) significantly increased the onset of acute signs of poisoning, time of death and prevented 4 h and 24 h death by 87.5
and 75%, respectively. Atropine injection at 2 mg/kg, i.m. 15 minutes before or immediately after oral dichlorvos dosing (18
mg/kg) causes significant decrease in the onset of acute signs of poisoning, time of death in comparison to diphenhydramine
group and significantly prevented 4 h and 24 h death by 87.5 and 75%, respectively in comparison to control group.
Diphenhydramine and atropine decreased the percentages occurrence of acute signs of poisoning and decreased the toxicity
score significantly in comparison to control group. The data of this study suggest that diphenhydramine have a protective and
therapeutic effects on acute dichlorvos poisoning in chicks which resembled that of atropine.
يعرب جعفر موسى | Yaareb Jaafar Mousa | 5562