Evaluation of the role of calcium channel blockers on treating the cardiac toxicity induced by theophylline overdose in albino rats

ABSTRACT

Theophylline is currently used to treat various illnesses [asthma, syndromes of airway obstructurion, bronchioliolitis in infants, etc]. It has a narrow therapeutic index with resulting higher incidence of toxicity and death. Central nervous system effects and cardiac toxicity manifestations are the main cause of death especially in elderly patients and neonates. Four major theories have been proposed to explain theophylline's harmacologic effects. The most recent one suggested that the drug's action may result direct from chanes in intracellular calcium transport. LSo the aim of our study is to evaluate the role of calcium channel blockers [CCBs] on treating the cardiac toxicity induced by theophylline overdose in albino rats. 35 mature albino rats of both ses were divided to 5 groups [n=7]. The first was injected with saline. Groups 2,3,4 and 5 were injected by 150mg/kg [LD95] of theophyline intraperitoneal. Then groups 3,4 and 5 were injected by therapeutic doses of CCBs [verapamil, diltiazem and nifedipine], respectively. The electgrocardiogram was recorded for all groups, serum creatine phosphokinase [CK], lactate dehydrogenase [LDH], K+ and Na+ were measured and hisopathological examination of the heart had been performed. Results indicate that groups 3,4 [treated with veraamil and deltiazem] shows improvement of the cardiac toxicity induced by theophylline overdose in the form of decrease S-T segment level, decrease of serum CK and LDH [P<0.001] and improvement of histopathological ischemic manifestations of the heart. Group 5 [treated with nifidepine] shows nonsignifidant changes