If two substances cancel each other out (1+1=0) in terms of drug interactions, this is called

If two substances cancel each other out (1+1=0) in terms of drug interactions, this is called

• A. Additive
• B. Synesthesia
• C. Antagonistic
• D. Eidetic

Answer: (C)

In drug interactions, how two substances influence each other can vary: they can add, boost beyond the sum, or dampen each other's effects. When two substances end up canceling each other out, that’s called antagonism. One drug blocks or reduces the effect of the other, so the overall response is smaller or even null. This differs from additive interactions, where the effects simply add up (1+1 equals 2), and from synergistic interactions, where the combined effect is greater than the sum. The other terms listed don’t fit this idea—synesthesia and eidetic refer to unrelated phenomena (sensory crossover and vivid memory). So the canceling-out scenario is best described as antagonistic.

In drug interactions, how two substances influence each other can vary: they can add, boost beyond the sum, or dampen each other's effects. When two substances end up canceling each other out, that’s called antagonism. One drug blocks or reduces the effect of the other, so the overall response is smaller or even null. This differs from additive interactions, where the effects simply add up (1+1 equals 2), and from synergistic interactions, where the combined effect is greater than the sum. The other terms listed don’t fit this idea—synesthesia and eidetic refer to unrelated phenomena (sensory crossover and vivid memory). So the canceling-out scenario is best described as antagonistic.