an agonist at a receptor that engages several post receptor biochemical processes to transduce its response

an agonist at a receptor that engages several post receptor biochemical processes to transduce its response. After some weeks of continued daily use of drug M, some of these "downstream" processes become less efficient, not responding as well as when she initiated therapy, resulting in reduced receptor responsiveness. You need to increase the dose to restore the therapeutic response she had been achieving. This is an example of _______.
Drug disposition tolerance
Drug resistance Pharmacodynamic tolerance
Tachyphylaxis