In large multicenter trials, few (if any) side effects have been noted in patients taking Saccharomyces boulardii for up to 15 months. Regardless of diarrhea type, Saccharomyces boulardii is often taken in doses of 500-2,000 milligrams in divided daily doses (three or four times daily). The brand name product, Ultra-Levure®, has been studied in doses of 2-4 capsules daily for up to eight months. For antibiotic-associated diarrhea, 1 gram daily for three days following completion of antibiotics has been used. Two sachets per day containing 5x109 colony forming units (CFU) per sachet has also been used for four weeks. One capsule twice daily has been used; duration was not noted. 250-500mg twice daily for up to two weeks following antibiotics has been used. Four capsules Ultra-Levure® daily for eight months has been used.
The most commonly used dose for Saccharomyces boulardii in children for the treatment of diarrhea is 250-600 milligrams daily for up to five days. This has been given alone and in combination with antibiotics.
Avoid in individuals with a known allergy or hypersensitivity to yeast, Saccharomyces boulardii, Saccharomyces cerevisiae, or other species in the Saccharomycetaceae family. Saccharomyces boulardii use may be associated with itching, urticaria ("hives"), and generalized skin eruptions.
Saccharomyces boulardii has been generally well tolerated in human studies for treatment of various diarrheal disorders. Symptoms of Saccharomyces cerevisiae infection included septic shock in more than one patient and fever in another. Symptoms of sepsis (infection) included increased white blood cell count, abdominal meteorism (swelling from gas), and respiratory insufficiency. In general, contamination occurred in patients with an indwelling vascular catheter.
Constipation, increased thirst, flatulence (gas), and bloating have been associated with Saccharomyces boulardii use. Use cautiously in patients with constipation.
Saccharomyces boulardii fungemia (fungal infection) has occurred. Avoid in patients with a yeast infection. Symptoms included septic shock in more than one patient and fever in another. Symptoms of sepsis include white blood cell count increase, abdominal meteorism, and respiratory insufficiency. In general, contamination occurred in patients with an indwelling vascular catheter.
Saccharomyces boulardii use may also cause Quincke's edema (swelling) or increases or decreases in blood pressure when used with MAOIs.
Saccharomyces boulardii is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence.