One way to deal with the wrong drug problem is to use different colors and shapes of bottles to represent different categories and dangerousness of drugs. Coloring can be added to the drug itself, such as using a red for more toxic medications, and green for more benign ones. A deeper shade of the color can represent an increased concentration.

Just like different shapes and colors of wine bottles are used for different wine categories.

I saw a show once which traced a medicine overdose to the bottles for the different strengths of the same drug being identical. The doctor just picked up the wrong one.