antagonist drug definition
antagonist-a drug that neutralizes or counteracts the effects of another drug. drug-a substance that is used as a medicine or narcotic. estrogen antagonist, tamoxifen-an antagonist for estrogen that is used in the treatment of breast cancer.narcotic antagonist-an antagonist used to counteract the effects of narcotics (especially to counteract the depression of respiration).strogen antagonist, tamoxifen-an antagonist for estrogen that is used in the treatment of breast cancer. narcotic antagonist-an antagonist used to counteract the effects of narcotics (especially to counteract the depression of respiration).