Taking two depressants such as a sleeping pill along with alcohol can result in:

drug antagonism
drug synergism
cancelling each other's effects
producing extreme drwosiness

drug synergism and producing extreme drowsiness. Mixing depressants can amplify the effects of each substance, leading to increased sedation and potential respiratory depression. This dangerous combination can also increase the risk of accidents, overdose, and other harmful consequences. It is important to always consult with a healthcare professional before mixing medications or alcohol.