Alterations in the biochemical indices in Wistar rats exposed to an overdose of codeine and dextromethorphan

OBJECTIVE: This study investigates the impact of repeated oral exposure to two cough syrups containing codeine and dextromethorphan (DXM) on male Wistar rats. METHODS: We divided 35 rats into seven groups of five rats each. Group A was given 0.5 mL of distilled water, Groups B, C, and D were given 0.1, 0.2 and 0.4 mL/kg body weight (b. w) of cough syrup containing codeine (CSC), respectively, and Groups E, F, and G were administered 0.1, 0.2 and 0.4 mL/kg b. w of cough syrup containing DXM, respectively. The treatment was continued for 28 days. The rats were euthanised under mild diethyl ether anaesthesia. The kidney, liver, and blood of the rats were examined for further analyses. RESULTS: Significant (p < 0.05) alterations were observed in the liver function tests: ALT, AST, ALP, albumin, and total bilirubin. All doses of CSC and DXM significantly increased the ALT levels (p < 0.05). Furthermore, similar significant alterations were observed for the kidney function parameters such as creatinine, urea, and uric acid (p < 0.05). All doses of DXM caused significant elevations in the levels of urea (p < 0.05). The histopathological evaluations also showed slight changes in the architecture of the liver, kidney, and brain tissues. CONCLUSION: The findings of this study suggest that overdose of these cough syrups may predispose the consumer to hepatic and renal injuries.