A drug with a 1:10 ED to LD ratio is _______________________ safe than a drug with a 1:100 ED to LD ration.

A drug with a 1:10 ED to LD ratio is _______________________ safe than a drug with a 1:100 ED to LD ration.

• A. A More
• B. B Less
• C. C Roughly the same
• D. D Much less

Answer: (B)

Safety margin is about how much larger the lethal dose is compared with the dose that produces the desired effect. If the ratio is 1:10, the lethal dose is only ten times the effective dose, giving a relatively small safety cushion. If the ratio is 1:100, the lethal dose is one hundred times the effective dose, providing a much bigger safety cushion. So the drug with a 1:10 ED to LD ratio has a smaller safety margin and is less safe than the one with a 1:100 ratio.

Safety margin is about how much larger the lethal dose is compared with the dose that produces the desired effect. If the ratio is 1:10, the lethal dose is only ten times the effective dose, giving a relatively small safety cushion. If the ratio is 1:100, the lethal dose is one hundred times the effective dose, providing a much bigger safety cushion. So the drug with a 1:10 ED to LD ratio has a smaller safety margin and is less safe than the one with a 1:100 ratio.