Probiotics: What You Should Know

Bacilli Bacteria

What are Probiotics and how can they help me?

Probiotics are live, non-pathogenic, microbes, and some can be found growing and multiplying in our gastrointestinal tracts: to us, they are commonly known as gut microflora, but can exist in different locations. To some this sounds scary, gross, or both; but these microorganisms are our friends. Probiotics, Pro = for, bio = life, are live microbial cultures that are ingested to exert a beneficial effect. These live cultures have been found useful in the restoration and stabilization of our normal intestinal flora.

How do they work?

Human intestinal microflora compete for epithelial cell area (the cell tissue of the intestinal tract), and ferment carbohydrates. It's in these two actions that they provide us with a first line of defense against pathogens and aid in the digestive processes of nutrient absorption and metabolism.

Lactobacillus and Bifidobacterium species ferment carbohydrates to produce lactic acid, acetic acid, and propionic acid. These lower the pH of the intestines and suppress the growth of various pathogenic bacteria. There is also come clinical evidence (not conclusive) that probiotics can improve immune function, reduce inflammation, and help prevent urinary tract infections through their competition in growth with other pathogenic bacteria.

Why Would I Take These?

Issue Suggested Probiotics*
Antibiotic Associated Diarrhea (AAD) Lactobacillus GG (Culturelle®), Saccharomyces boulardii (Florastor®)
Constipation Bifidobacterium animalis (Activia®), Lactobacillus casei (Yakult®)
Clostridium Difficle Saccharomyces boulardii (Florastor®)
Irritable Bowel Syndrome (IBS) Bifidobacterium infantis (Align®), Lactobacillus acidophilus with Streptococcus thermophilus (most yogurts)
Rotavirus Lactobacillus GG (Culturelle®)
Ulcerative Colitis Lactobacillus, Bifidobacterium, and Streptococcus thermophilus (VSL3® containing many different species of each)

*these have clinically significant evidence that such "suggested probiotics" are helpful with each "issue", though most evidence is not conclusive at this time (June 2012).

Who should not use probiotics?

  • Patients who are immunocompromised and/or are taking immunosuppressants or chemotherapeutic agents (chance of pathogenic colonization);
  • Patients in the presence of a high fever; or
  • Patients with an impaired epithelial barrier, acute pancreatitis, cardiac calcular disease.

Probiotics should NOT be confused with Prebiotics, as these are not the same. Prebiotics are used to promote the growth of healthy bacteria in our intestines and usually contain various carbohydrates that promote the growth of favorable bacteria in the intestinal tract. Prebiotics can be used in combination with probiotics.

To optimize the results from taking such products, if taking antibiotics, they should not be taken at the same time. The probiotic should be taken 2 hours after each antibiotic dose. Also, as S. boulardii (the active microbe in Florastor®) is a yeast, it will be rendered inneffective with the cocommitent use of antifungals such as metronidazole. Most capsules may be opened and their contents sprinkled over cool food or mixed into cool liquids

Are There Side Effects?

As with any oral medication, there may be some side effects with taking these medications. In the probiotic fermentation process gas is created, thus you may experience flatulence and/or GI bloating. If these symptoms worsen while you are taking probiotics, it is advisable to stop probiotic therapy.

Bottom Line About Probiotics:

Though there is significant clinical evidence that good intestinal microflora are important to our first line of defense, there is still insufficient conclusive evidence that probiotics are the indeed 100% effective. There are many types of probiotics, and each have many different marketed claims about their effectiveness. If you are experiencing irregularity; are taking an antibiotic and experiencing GI issues; or just have some general questions about whether a probiotic might be a choice for you, then talk with your physician or pharmacist: a probiotic may be a simple and effective means of finding some relief.


Jeremy KW Spiewak, Pharmacy Intern, CPhT, MA RPhT, BA Chemistry, Doctor of Pharmacy Candidate at Massachusetts College of Pharmacy and Health Sciences


In The News

Levoxyl® Voluntarily Recalled at the Pharmacy Level

Pfizer has conducted a careful risk assessment and has determined that there is little to no risk of any adverse health events due to this packaging defect.  Regardless, Pfizer, King, and the FDA have worked together and decided to voluntarily recall at the pharmacy level, all Levoxyl strengths.

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Probiotics. Drug Facts and Comparisons® eAnswers [online]. 2012. Available through Wolters Kluwer Health, Inc. Accessed June 2012.

Probiotics. Detail Document 250908. Pharmacist’s Letter v 25(9). Stockton, CA: Therapeutic Research Company, 2009.

Wick, Jeannette Y. (2011) Move Over, Standard Drugs: Probiotics Are Coming. Pharmacy Times. Pharmacy and Healthcare Communications LLC, v7:11, pp 41-42.

Original Published:June 2012

Revised:June 2012