A drug that counteracts the effects of other drugs is called an:

A drug that counteracts the effects of other drugs is referred to as an antagonist. Antagonists work by binding to specific receptors in the body without activating them, effectively blocking or inhibiting the action of other substances that would normally bind to those receptors. This property makes antagonists essential in medical treatments where it’s necessary to negate the effects of drugs that may be causing adverse reactions or to block excessive physiological responses.

For example, in the case of opioid overdoses, antagonists like naloxone are used to reverse the effects of opioids by displacing them from their receptors, thus restoring normal respiratory function. This action highlights the significant role antagonists play in pharmacology, where controlling or opposing the effects of certain drugs is crucial for patient safety and therapeutic efficacy.