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Metronid-Tetracyc-Bis Subsal

Drug Information

Common brand names:

Helidac

Summary of Interactions with Vitamins, Herbs, & Foods

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Folic Acid

    Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K. This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study. The importance of this interaction is unknown.

    Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin. Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.

  • Potassium

    Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K. This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study. The importance of this interaction is unknown.

    Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin. Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.

  • 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 B2

    Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K. This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study. The importance of this interaction is unknown.

  • Vitamin B6

    Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K. This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study. The importance of this interaction is unknown.

  • 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.

  • Vitamin B3 (Niacin)

    Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin. Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.

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

Reduce Side Effects

  • Probiotics

    The yeast Saccharomyces boulardii may help restore microbial balance in the intestines and prevent pseudomembranous colitis (PMC), an intestinal disorder caused by infection with Clostridium difficile. Even when Clostridium difficile is successfully treated with antibiotics, symptoms recur in about 20% of cases. Saccharomyces boulardii has been shown in controlled trials to reduce recurrences when given as an adjunct to antibiotic therapy.

  • Vitamin C

    Tooth discoloration is a side effect of minocycline observed primarily in young children, but it may occur in adults as well. Vitamin C supplementation may prevent staining in adults taking minocycline.

  • Brewer’s Yeast

    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. 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.

    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.

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

Support Medicine

  • Bromelain

    When taken with amoxicillin, bromelain was shown to increase absorption of amoxicillin in humans. When 80 mg of bromelain was taken together with amoxicillin and tetracycline, blood levels of both drugs increased, though how bromelain acts on drug metabolism remains unknown. An older report found bromelain also increased the actions of other antibiotics, including penicillin, chloramphenicol, and erythromycin, in treating a variety of infections. In that trial, 22 out of 23 people who had previously not responded to these antibiotics did so after adding bromelain taken four times per day.

    Doctors will sometimes prescribe enough bromelain to equal 2,400 gelatin dissolving units (listed as GDU on labels) per day. This amount would equal approximately 3,600 MCU (milk clotting units), another common measure of bromelain activity.

  • 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.

Reduces Effectiveness

  • Calcium

    Many minerals can decrease the absorption of tetracycline, thus reducing its effectiveness. These minerals include aluminum (in antacids), calcium (in antacids, dairy products, and supplements), magnesium (in antacids and supplements), iron (in food and supplements), zinc (in food and supplements), and others.

  • Iron

    Many minerals can decrease the absorption of tetracycline, thus reducing its effectiveness. These minerals include aluminum (in antacids), calcium (in antacids, dairy products, and supplements), magnesium (in antacids and supplements), iron (in food and supplements), zinc (in food and supplements), and others.

  • 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.

  • Magnesium

    Many minerals can decrease the absorption of tetracycline, thus reducing its effectiveness. These minerals include aluminum (in antacids), calcium (in antacids, dairy products, and supplements), magnesium (in antacids and supplements), iron (in food and supplements), zinc (in food and supplements), and others.

  • Zinc

    Taking calcium, iron, magnesium, or zinc at the same time as minocycline can decrease the absorption of both the drug and the mineral. Therefore, calcium, iron, magnesium, or zinc supplements, if used, should be taken an hour before or after the drug.

Potential Negative Interaction

  • Barberry

    Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera. Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients. Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

  • Goldenseal

    Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera. Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients. Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

  • Oregon Grape

    Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera. Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients. Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

  • Meadowsweet

    Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet (Filipendula ulmaria), poplar (Populus tremuloides),willow (Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies. Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might. No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs. Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet (Filipendula ulmaria), poplar (Populus tremuloides),willow (Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies. Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might. No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs. Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

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

    Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet (Filipendula ulmaria), poplar (Populus tremuloides),willow (Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies. Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might. No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs. Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet (Filipendula ulmaria), poplar (Populus tremuloides),willow (Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies. Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might. No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs. Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

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

Explanation Required 

  • Barberry

    Berberine is a chemical extracted from goldenseal (Hydrastis canadensis),barberry (Berberis vulgaris), and Oregon grape (Berberis aquifolium), which has antibacterial activity. However, one double-blind study found that 100 mg berberine given with tetracycline (a drug closely related to doxycycline) reduced the efficacy of tetracycline in people with cholera. In that trial, berberine may have decreased tetracycline absorption. Another double-blind trial found that berberine neither improved nor interfered with tetracycline effectiveness in cholera patients. Therefore, it remains unclear whether a significant interaction between berberine-containing herbs and doxycycline and related drugs exists.

  • Milk Thistle

    Milk thistle has been reported to protect the liver from harm caused by some prescription drugs. While milk thistle has not yet been studied directly for protecting people against the known potentially liver-damaging actions of metronidazole, it is often used for this purpose.

  • 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.

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

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