Are sedatitive medication or drugs classed as "hypnotics" a problem when taken with ethanol?

Interact. Alcohol and sedative hypnotics can have additive effects. This can increase the risk of respiratory depression, motor abnormalities, poor judgement, low blood pressure, balance problems, etc ... And, oh yeah, risk of death. They are not to be mixed.
Both. Neither should be taken at the same time you are drinking alcohol. The consequences can be severe, up to and including death.