What is the medical term meaning illness that unfavorable response to a prescribed treatment?

The medical term meaning illness that unfavorable response to a prescribed treatment is "refractory disease." When a disease or medical condition does not respond as expected to the usual treatment, it is referred to as refractory.

Refractory diseases can be challenging for healthcare providers to manage as they may require alternative treatment strategies or changes in the treatment plan. In some cases, refractory diseases may indicate the need for additional diagnostic tests to identify underlying factors contributing to the lack of response to treatment.