Taking a drug as the active enantiomer instead of the racemic mixture can be advantageous because the active enantiomer is usually responsible for the desired therapeutic effects, while the inactive enantiomer can contribute to unwanted side effects or have no therapeutic value. By using the active enantiomer, the drug's efficacy can be maximized, potentially reducing side effects and improving patient outcomes. Additionally, testing and developing a single enantiomer may be more cost-effective and efficient compared to handling and studying a racemic mixture.