ATC Class:G01AX14

AHFS Class:

• Antidiarrhea Agents 56:08

Generic Name(s):

• Lactobacillus Acidophilus

Lactobacillus acidophilus is a bacterium that produces lactic acid, thereby creating an environment unfavorable to the overgrowth of potentially pathogenic fungi and bacteria (including putrefactive bacteria) and favoring establishment of an aciduric flora.

Diarrhea

Lactobacillus acidophilus and L. bulgaricus have been used for more than 75 years in the treatment of uncomplicated diarrhea, particularly that caused by modification of the intestinal flora by antibiotics. Lactobacillus preparations may assist in reestablishing the normal physiologic and bacterial flora of the intestinal tract. Lactobacillus acidophilus has also been used in patients with infectious diarrhea, ulcerative colitis, irritable colon, diverticulitis, colostomies with either diarrhea or constipation, functional constipation, mucous or spastic diarrhea, and diarrhea following amebiasis. However, there currently is a lack of substantial evidence from well-designed, controlled studies to support claims of efficacy for Lactobacillus preparations in the treatment of diarrhea. Therefore, while these preparations may remain on the market in the US as foods or food (nutritional) supplements, the manufacturers can no longer claim usefulness in the treatment of diarrhea.

Other Uses

Limited studies have indicated that Lactobacillus acidophilus may offer relief to patients with hives, fever blisters, canker sores, and adolescent acne, but results in these largely self-limiting conditions have been equivocal.

Lactobacillus acidophilus is administered orally, preferably with milk, fruit juice, or water. The conventional capsules, tablets, and granules may be chewed or swallowed whole, and the granules or contents of Intestinex^® capsules may be added to or taken with cereal, food, milk, fruit juice, or water. The commercially available enteric-coated capsules should be swallowed whole. Dosage of the commercial preparation containing Lactobacillus acidophilus and sodium carboxymethylcellulose is 2 capsules 2-4 times daily. Dosage of the commercial preparations containing Lactobacillus acidophilus and L. bulgaricus is 2 capsules, 4 tablets, or 1 packet of granules 3 or 4 times daily. Dosage of the commercially available enteric-coated capsules containing Lactobacillus acidophilus and L. casei is 1 capsule daily for the first 2 weeks of therapy; dosage may then be increased up to a maximum of 3 capsules daily if necessary.

Lactobacillus acidophilus may produce an increase in intestinal flatus at the beginning of therapy, but this usually subsides with continued therapy. For self-medication of diarrhea, Lactobacillus acidophilus preparations should generally not be used for longer than 2 days or in the presence of a high fever unless otherwise directed by a physician. One manufacturer recommends that Lactobacillus acidophilus not be used for treatment of diarrhea in infants and children younger than 3 years of age unless under the direction and supervision of a physician. Individuals sensitive to milk products should not use the drug.

Pharmacology

Through the production of lactic acid, Lactobacillus acidophilus, a natural inhabitant of the GI tract, creates an environment unfavorable to the overgrowth of potentially pathogenic fungi and bacteria (including putrefactive bacteria) and favors establishment of an aciduric flora. Some commercially available preparations of Lactobacillus acidophilus also contain a standardized viable culture of Lactobacillus bulgaricus. Lactobacillus bulgaricus is not a normal inhabitant of the bowel but it provides a transient beneficial flora and enhances the growth of desirable bacteria by forming lactic acid on fermentation of carbohydrates.

Chemistry and Stability

Chemistry

Lactobacillus acidophilus is an acid-producing bacterium prepared in a concentrated, dried, and viable culture for oral administration. No methods of standardization of the cultures used in the commercial preparations have been published.

Stability

Commercial preparations should be stored at 2-8°C. The commercially available Lactinex^® tablets and granules carry an 18-month expiration date and the capsules a 2-year expiration date.