Final answer:
Clostridium Difficile Associated Diarrhea is the most life-threatening adverse reaction to Omeprazole, leading to severe symptoms and potentially serious complications.
Step-by-step explanation:
The most life-threatening adverse reaction while taking Omeprazole is c. Clostridium Difficile Associated Diarrhea. While common side effects can include aches, headaches, nausea, and changes in bowel habits (diarrhea or constipation), the risk of developing C. difficile-associated diarrhea is considered serious. This infection can cause severe stomach cramps, diarrhea that can be bloody, and vomiting. In some cases, approximately 5-10% of infected individuals, it can lead to life-threatening complications, such as toxic megacolon or sepsis. This is particularly concerning because the use of antibiotics and proton pump inhibitors like Omeprazole can disrupt the natural gut flora, creating an environment conducive for C. difficile overgrowth.