Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from drug tolerance which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.
Having a (often acquired) resistance against a drug, by developing modified targets, increasing the degradation of an active compound or by exporting it out of a cell.
The capacity of disease-causing pathogens to withstand drugs previously toxic to them. Over time, multiple generations of disease-causing bacteria and viruses mutate to compensate for the threat posed to them by drugs. Drug resistance is a serious threat to medical progress against infectious diseases such as tuberculosis, malaria, diarrhea, sexually transmitted diseases (STDs), and various tropical diseases. The effectiveness of drugs intended to fight these infections is diminishing as drug-resistant microbes develop and spread.
The ability to withstand drug treatment.