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Antidiarrhea Medications


Diarrhea is something that everyone has experienced before. Not only is it uncomfortable, but it can create an awkward situation when it occurs at the wrong time. In the case of severe diarrhea, extra care needs to be taken as well.


Currently, there are 2 types of over-the-counter (OTC) medications available in Canada:


Loperamide (Imodium®)

Loperamide slows down the peristalsis of the intestines, allowing more time for water absorption from the stool in the intestines. It can also reduce the efficiency of the muscle reflex response in the intestines, creating a rapid response to the drug. Although Loperamide belongs to the opioid drug family, little amounts of the drug are able to reach systemic circulation, therefore, it will have no side effects that exist in other opioids. Taking it according to the labelled instructions will not lead to opioid dependence.




Bismuth Salicylate (Pepto Bismol®, Kaopectate®)

Bismuth Salicylate is derived from salicylic acid (also known as Aspirin) through a chemical process. In addition to slight anti-inflammatory effects, it also has anti-diarrheal effects due to the promotion of water and electrolyte absorption in the intestine that slow down peristalsis strength. Bismuth Salicylate is also known to have antiemetic, slight antimicrobial, and antacid properties. It is recommended for travel as it can help with traveler's diarrhea caused by consumption of unsanitary food. After administration, the tongue and stool can turn black, however, it is a normal occurrence related to the drug. As Bismuth Salicylate is a derivative of salicylic acid/aspirin, individuals allergic to aspirin, pregnant women, and breast-feeding mothers should seek professional advice before taking this drug.

Like all diseases, if the cause of the disease is found, then the right treatment for you can be better determined. Most causes of diarrhea are usually not difficult to determine.

Based on the following symptoms, the recommended choice of treatment is listed below:


Only diarrhea (no vomiting or fever):

In this situation, it is possible that the consumption of food that one has trouble digesting occurred, such as people with lactose intolerance consuming dairy products. Consumption of too much oil can also lead to such symptoms. Immediate administration of Loperamide would be the recommended treatment method in this case. Adults can take 2 tablets initially, with additional doses later if needed at a maximum of 8 tablets per day.



Diarrhea with Vomiting (no fever):

It is possible that bacteria or viruses have entered your gastrointestinal system through ingestion, such as consumption of unsanitary food or handling food with unclean hands. If the vomiting and diarrhea are mild, it is not recommended to start anti-diarrheal medications yet as diarrhea can expel the bacteria/viruses in the gastrointestinal system as soon as possible (antiemetic medicine can be taken as soon as possible however). When the diarrhea has an appearance close to clear water, you can then take anti-diarrheal medication to stop the diarrhea. In this situation, Bismuth Salicylate is the recommended treatment option as it has a slight bactericidal effect and also protects the inner wall of the stomach, reducing the chance of bacteria/viruses being absorbed into the body. Children 3+ to adults can take appropriate doses according to their age every half to one hour, up to 8 doses daily. Additionally, consumption of electrolyte-containing beverages (Gatorade..


etc) is recommended as well to avoid dehydration and electrolyte loss caused by vomiting or diarrhea.


Diarrhea with Vomiting and Fever:

In this situation, it is possible that bacteria or viruses have reached other body systems from the gastrointestinal system. It is recommended for you to seek medical attention as soon as possible, and consult the doctor to diagnose whether antibiotics should be taken.


Diarrhea and/or Severe bowel pain and/or alkaline discharge and/or bloody or black stool:

Seek medical attention as soon as possible for diagnosis of possible intestinal ulcers, Irritable Bowel Syndrome or other unknown causes


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