Acute toxicity of tramadol in African catfish <i>Clarias gariepinus</i> (Burchell, 1822)

Abstract

Tramadol is among the most famous analgesic drugs used for the management, treatment and relief of moderate to severe pain condition. The present study investigated the effect of acute toxicity (LC₅₀) of tramadol on juvenile Clarias gariepinus. A total number of one hundred and eighty healthy juveniles of freshwater catfish C. gariepinus with total mean weight and length of (455.3 ± 50 g and 163.9 ± 18.2 cm) were used for the study. The 24, 48, 72 and 96 hour LC₅₀ of C. gariepinus exposed to tramadol were 213.01(151.94 – 613.23), 109.86 (66.36 – 936.04), 74.02(4.51 – 205.10) and 63.34(29.50 – 95.83) mg/L respectively. The safe levels of tramadol in C. gariepinus varied from 6.33x10-1 to 6.33x10^-4mg/L. The toxic unit of tramadol is 0.63 indicating that the drug is toxic to C. gariepinus. Fish exposed to tramadol showed some significance abnormal behavioural responses such as, reduced agility, abnormal mucus secretion, skin coloration, opercula movement and air gulping, very poor swimming rate and mortality increased with increase in the exposure duration and concentrations except for the control. The results of the present study demonstrated that tramadol is toxic to fish and its use should be monitored in the aquatic biota to safeguard non-target organisms.