Drug Information

Griseofulvin is an antifungal drug used to treat ringworm infections of the skin, hair, and nails caused by specific fungi.

Common brand names:

Gris-PEG, Fulvicin U/F, Grifulvin V, Grisactin

Summary of Interactions with Vitamins, Herbs, & Foods

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Vitamin B12

    Neomycin can decrease absorption or increase elimination of many nutrients, including calcium, carbohydrates, beta-carotene, fats, folic acid, iron, magnesium, potassium, sodium, and vitamin A, vitamin B12, vitamin D, and vitamin K. Surgery preparation with oral neomycin is unlikely to lead to deficiencies. It makes sense for people taking neomycin for more than a few days to also take a multivitamin-mineral supplement.

  • Vitamin K

    Several cases of excessive bleeding have been reported in people who take antibiotics. This side effect may be the result of reduced vitamin K activity and/or reduced vitamin K production by bacteria in the colon. One study showed that people who had taken broad-spectrum antibiotics had lower liver concentrations of vitamin K2 (menaquinone), though vitamin K1 (phylloquinone) levels remained normal. Several antibiotics appear to exert a strong effect on vitamin K activity, while others may not have any effect. Therefore, one should refer to a specific antibiotic for information on whether it interacts with vitamin K. Doctors of natural medicine sometimes recommend vitamin K supplementation to people taking antibiotics. Additional research is needed to determine whether the amount of vitamin K1 found in some multivitamins is sufficient to prevent antibiotic-induced bleeding. Moreover, most multivitamins do not contain vitamin K.

Reduce Side Effects

  • Probiotics

    A common side effect of antibiotics is diarrhea, which may be caused by the elimination of beneficial bacteria normally found in the colon. Controlled studies have shown that taking probiotic microorganisms—such as Lactobacillus casei, Lactobacillus acidophilus, Bifidobacterium longum, or Saccharomyces boulardii—helps prevent antibiotic-induced diarrhea.

    The diarrhea experienced by some people who take antibiotics also might be due to an overgrowth of the bacterium Clostridium difficile, which causes a disease known as pseudomembranous colitis. Controlled studies have shown that supplementation with harmless yeast—such as Saccharomyces boulardii or Saccharomyces cerevisiae (baker’s or brewer’s yeast)—helps prevent recurrence of this infection.

    Treatment with antibiotics also commonly leads to an overgrowth of yeast (Candida albicans) in the vagina (candida vaginitis) and the intestines (sometimes referred to as “dysbiosis”). Controlled studies have shown that Lactobacillus acidophilus might prevent candida vaginitis.

Support Medicine

  • Probiotics
    In one study, taking 500 mg of Saccharomyces boulardii twice daily enhanced the effectiveness of the antibiotic vancomycin in preventing recurrent clostridium infection. Therefore, people taking antibiotics who later develop diarrhea might benefit from supplementing with saccharomyces organisms.
  • High-Fat

    Food, especially with high fat content, increases griseofulvin absorption. It is recommended to take griseofulvin with food to maximize absorption of the drug. People on low-fat diets who are taking griseofulvin should talk with their doctor or pharmacist.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Vitamin E

    Adding 50 IU of vitamin E per day was reported to increase blood levels of this drug within four weeks in children, allowing the drug dose to be cut in half. Reducing the amount of griseofulvin should decrease the likelihood of side effects. This evidence is preliminary, so people taking griseofulvin should not supplement vitamin E on their own but may wish to discuss this matter with their doctor.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

Reduces Effectiveness

  • Khat

    Khat (Catha edulis) is an herb found in East Africa and Yemen that has recently been imported into the United States. Studies have shown that chewing khat significantly reduces the absorption of ampicillin, which might reduce the effectiveness of the antibiotic. Therefore, people taking ampicillin should avoid herbal products that contain khat.

Potential Negative Interaction

  • none

Explanation Required 

  • none

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.