Effect of Chronic Oral Exposure to Overdose of Cough Syrups on Rate of DNA Fragmentation in Liver and Brain of Wistar Rats

This study was designed to determine the effect of chronic oral exposure of overdose of cough syrups containing codeine (CSC) and dextromethorphan (DXM) on the rate of deoxyribonucleic acid (DNA) fragmentation in the liver and brain of Wistar rats. Forty-five rats divided into 9 groups of 5 rats were used. Groups 1, 2, 3, and 4 were treated with 0.1, 0.2, 0.4, and 0.6 mg/kg b/w of CSC, and Groups 5, 6, 7, and 8 were treated with the same doses of DXM, respectively for 21 days. Group 9 (control) received distilled water once daily and all the rats were sacrificed 24 hours after the last treatment. DNA analysis was done on the harvested liver and brain. Significant reductions (p < 0.05) in the rate of DNA fragmentation of the liver tissues were observed in all the groups treated with the overdose of cough syrups when compared to the control. However, there was no significant difference in the rate of DNA fragmentation of the brain in all the groups treated with cough syrup as compared to the control. The result indicated that overdose of cough syrup may cause suppressed DNA fragmentation of the liver thereby predisposing the organ to dysfunctions and untimely aging.