In the present work, a voltammetric method using differential pulse voltammetric technique for the assessment of antipyretic and analgesic drug, acetaminophen was developed. The CuO nanoparticles were prepared and characterized. A glassy carbon electrode (GCE) fabricated with the suspension of CuO nanoparticles (CuONPs) and multi-walled carbon nanotubes (MWCNTs) were used. The modified electrode showed improved anodic peak current by introducing an anionic surfactant sodium dodecyl sulphate in phosphate buffer solution. The consequence of pH of supporting electrolyte, amount of nanoparticles suspension and surfactant concentration was investigated at a physiological pH of 7.4. Using differential pulse voltammetry, the fabricated electrode showed linear dynamic range from 9 to 160 nM of acetaminophen concentration. From the calibration plot, the computed detection limit was 5.06 nM and quantification limit was 16.88 nM. The developed method was checked for its reproducibility and assay during a day and intraday as well. The developed process was fruitfully applied to detect acetaminophen in pediatric oral suspensions administered to infants.