Synergism in pharmacology is defined as?

• A. Immediate drug tolerance develops after first exposure.
• B. A combination of two drugs produces a greater effect than the sum of the individual effects.
• C. Two drugs cancel each other out.
• D. There is no interaction between drugs.

Answer: (B)

Synergism means two drugs interact to produce a larger effect than you’d predict by simply adding their separate effects. If Drug A gives a certain level of effect and Drug B adds another, their combined effect ends up greater than the sum of each alone. For example, if A provides 10 units of relief and B provides 15, an additive expectation would be 25, but a synergistic pair might yield something much higher, like 40. This amplified result happens because the drugs enhance each other’s actions or hit different steps in the same process.

This matters for driving safety because combining substances that act synergistically can greatly impair judgment, reaction time, and coordination beyond what you’d expect from either drug alone. Always follow medical guidance and avoid mixing medications or substances that could interact strongly.

Other options don’t fit because tolerance after first exposure describes a diminishing response rather than a greater combined effect; antagonism is when substances reduce each other’s effects; and no interaction would mean the drugs don’t affect each other at all.