Final answer:
Dantrium, or dantrolene, commonly causes diarrhea as a side effect due to its muscle relaxant properties, affecting the muscles in the digestive system.
Step-by-step explanation:
Dantrium, known generically as dantrolene, is a muscle relaxant used to treat muscle spasms and other conditions related to abnormal muscle contractions. When considering the side effects of Dantrium, it's important to note that one of the common gastrointestinal side effects is diarrhea. Contrary to causing constipation, Dantrium can lead to an increase in bowel movements, which can be attributed to its effects on muscle relaxation, including those muscles within the digestive system. Therefore, the answer to the question is 'b) Diarrhea.' It isn’t related to water following K+ to make urine or osmotic balance between waste matter and bodily fluids as those are generally connected to the functions of the kidneys and body fluids respectively.