One of my patients developed a "locked jaw" 10 minutes after I gave him IV benadryl. He wrote down, as he could not talk, that he needed more IV benadryl to fix the problem. I stated, "if I call the doctor to ask for more IV benadryl for an adverse reaction to IV benadryl he is most likely going to discontinue the medication completely, not order more of it." He begged for me to not call the doctor. I called the doctor, he discontinued the medication. The patient threatened to leave AMA and called the nursing supervisor.
Moral of the story: If you want more of a medication, don't fake a reaction to it.