Final answer:
The term for when one drug's effect is increased when taken with another drug is called a synergistic interaction. This can lead to a greater combined effect, which is beneficial in medical treatments like using trimethoprim and sulfamethoxazole together for a bactericidal effect.
Step-by-step explanation:
The term that describes the process when the effect of one drug is increased or potentiated when given with another drug is known as a synergistic interaction. This can result in a greater combined effect than when either drug is given alone. An example of this is the use of the drugs trimethoprim and sulfamethoxazole (Bactrim), which, when used together, yield a bactericidal effect, whereas individually, they are only bacteriostatic. The ability of drugs to act as synergists or antagonists in the body illustrates their complex interactions with the endogenous neurotransmitter systems. Drug synergy is important in the context of prescribing medications, as it may result in the need for lower dosages of each drug, reducing potential side effects or toxicity.