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Tobramycin-Dexamethasone

Drug Information

Common brand names:

TobraDex

Summary of Interactions with Vitamins, Herbs, & Foods

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Oral corticosteroids reduce absorption of calcium and interfere with the activation and metabolism of the vitamin, increasing the risk of bone loss. Doctors can measure levels of activated vitamin D (called 1,25 dihydroxycholecalciferol) to determine whether a deficiency exists; if so, activated vitamin D is only available by prescription. A study of rheumatoid arthritis patients treated with low amounts of prednisone found that those who received 1,000 mg of calcium per day plus 500 IU of vitamin D per day for two years experienced no bone loss during that time period. An analysis of properly conducted trials concluded that supplementation with vitamin D and calcium was more effective than placebo or calcium alone in protecting against corticosteroid-induced osteoporosis. Most doctors recommend 1,000 mg of calcium and 400–800 IU vitamin D per day for the prevention of osteoporosis.

  • Folic Acid

    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.

  • 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

    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.

  • Calcium

    Oral corticosteroids reduce absorption of calcium and interfere with the activation and metabolism of the vitamin, increasing the risk of bone loss. Doctors can measure levels of activated vitamin D (called 1,25 dihydroxycholecalciferol) to determine whether a deficiency exists; if so, activated vitamin D is only available by prescription. A study of rheumatoid arthritis patients treated with low amounts of prednisone found that those who received 1,000 mg of calcium per day plus 500 IU of vitamin D per day for two years experienced no bone loss during that time period. An analysis of properly conducted trials concluded that supplementation with vitamin D and calcium was more effective than placebo or calcium alone in protecting against corticosteroid-induced osteoporosis. Most doctors recommend 1,000 mg of calcium and 400–800 IU vitamin D per day for the prevention of osteoporosis.

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

    Preliminary data suggest that corticosteroid treatment increases chromium loss. Double-blind trials are needed to confirm these observations.

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

    Calcium , magnesium, and potassium depletion requiring prolonged replacement were reported in a child with tetany who had just completed a three-week course of i.v. tobramycin. The authors suggest this may have been due to kidney damage related to the drug. Seventeen patients with cancer developed calcium, magnesium, and potassium depletion after treatment with aminoglycoside antibiotics, including tobramycin. The authors suggested a possible potentiating action of tobramycin-induced mineral depletion by chemotherapy drugs, especially doxorubicin (Adriamycin®).

    Until more is known, people receiving i.v. tobramycin should ask their doctor about monitoring calcium, magnesium, and potassium levels and the possibility of mineral replacement.

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

    A controlled trial found that a single dose of the synthetic corticosteroid dexamethasone suppressed production of melatonin in nine of 11 healthy volunteers. Further research is needed to determine if long-term use of corticosteroids interferes in a meaningful way with melatonin production, and whether supplemental melatonin would be advisable for people taking corticosteroids.

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

    Oral corticosteroids have been found to increase urinary loss of vitamin K, vitamin C, selenium, and zinc. The importance of these losses is unknown.

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

    Oral corticosteroids have been found to increase urinary loss of vitamin K, vitamin C, selenium, and zinc. The importance of these losses is unknown.

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

    Oral corticosteroids have been found to increase urinary loss of vitamin K, vitamin C, selenium, and zinc. The importance of these losses is unknown.

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

Reduce Side Effects

  • Oral corticosteroids reduce absorption of calcium and interfere with the activation and metabolism of the vitamin, increasing the risk of bone loss. Doctors can measure levels of activated vitamin D (called 1,25 dihydroxycholecalciferol) to determine whether a deficiency exists; if so, activated vitamin D is only available by prescription. A study of rheumatoid arthritis patients treated with low amounts of prednisone found that those who received 1,000 mg of calcium per day plus 500 IU of vitamin D per day for two years experienced no bone loss during that time period. An analysis of properly conducted trials concluded that supplementation with vitamin D and calcium was more effective than placebo or calcium alone in protecting against corticosteroid-induced osteoporosis. Most doctors recommend 1,000 mg of calcium and 400–800 IU vitamin D per day for the prevention of osteoporosis.

  • 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.

  • 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.
  • Chromium

    Preliminary data suggest that supplementation with chromium (600 mcg per day in the form of chromium picolinate) may prevent corticosteroid-induced diabetes. Double-blind trials are needed to confirm these observations.

    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.

  • Horny Goat Weed

    According to preliminary human studies, horny goat weed offset some of the side effects of corticosteroids.

  • 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.
  • N-Acetyl Cysteine

    One preliminary study found that in people with fibrosing alveolitis (a rare lung disease), supplementation with 600 mg N-acetyl cysteine three times per day increased the effectiveness of prednisone therapy.

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

Reduces Effectiveness

  • 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

    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.

  • 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

  • Use of corticosteroids may be associated with loss of certain minerals, called electrolytes. Herbs with a diuretic action (in other words, they promote fluid loss from the body through an increase in urine production) may accelerate the electrolyte loss caused by corticosteroids. Such herbs include asparagus root, butcher’s broom, cleavers, corn silk, juniper, mate, and parsley. This interaction is theoretical and has not been reported in the medical literature.

    Use of buckthorn (Rhamnus catartica, Rhamnus frangula, Frangula alnus) or alder buckthorn (Rhamnus catartica, Rhamnus frangula), for more than ten days consecutively may cause a loss of electrolytes (especially the mineral potassium). Because corticosteroids also cause potassium loss, buckthorn or alder buckthorn should be used with caution if corticosteroids are being taken.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Like diuretic herbs, herbs with a laxative action could theoretically increase electrolyte loss associated with corticosteroid use. Such herbs include aloe, buckthorn, cascara sagrada, rhubarb, and senna. This interaction is theoretical and has not been reported in the medical literature.

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

    Corticosteroids may increase the body’s loss of magnesium. Some doctors recommend that people taking corticosteroids for more than two weeks supplement with 300–400 mg of magnesium per day. Magnesium has also been reported to interfere with the absorption of dexamethasone.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Oral corticosteroids cause both sodium and water retention. People taking corticosteroids should talk with their doctor about whether they should restrict salt intake.

    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.

  • Licorice

    Licorice (Glycyrrhiza glabra) extract was shown to decrease the elimination of prednisone in test tube studies. If this action happens in people, it might prolong prednisone activity and possibly increase prednisone-related side effects. A small, controlled study found that intravenous (iv) glycyrrhizin (an active constituent in licorice) given with iv prednisolone prolonged prednisolone action in healthy men. Whether this effect would occur with oral corticosteroids and licorice supplements is unknown.

    An animal study has shown that glycyrrhizin prevents the immune-suppressing actions of cortisone—the natural corticosteroid hormone produced by the body. More research is necessary to determine if this action is significant in humans taking oral corticosteroids. Until more is known, people should not take licorice with corticosteroids without first consulting a doctor.

  • Taking the oral corticosteroid methylprednisolone with grapefruit juice has been shown to delay the absorption and increase the blood concentration of the drug. The mechanism by which grapefruit juice increases the concentration of methylpredniolone in the blood is not known, but it is suspected that it may interfere with enzymes in the liver responsible for clearing the drug from the body. In certain people, grapefruit juice may, therefore, enhance the effects of methylprednisolone. The combination should be avoided unless approved by the prescribing doctor.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Oral corticosteroids can cause loss of body protein. For this reason, medical doctors sometimes recommend a high-protein diet for people taking these drugs. However, people with diseases that cause kidney damage should not consume too much protein, as this could worsen their condition. A high-protein diet should be used only after consulting a doctor.

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

    Corticosteroids may increase the body’s loss of magnesium. Some doctors recommend that people taking corticosteroids for more than two weeks supplement with 300–400 mg of magnesium per day. Magnesium has also been reported to interfere with the absorption of dexamethasone.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Pomegranate juice has been shown to inhibit the same enzyme that is inhibited by grapefruit juice. The degree of inhibition is about the same for each of these juices. Therefore, it would be reasonable to expect that pomegranate juice might interact with oral corticosteroids in the same way that grapefruit juice does.

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

    In some people, treatment with corticosteroids can impair wound healing. In one study, topical or internal vitamin A improved wound healing in eight of ten patients on corticosteroid therapy. In theory, vitamin A might also reverse some of the beneficial effects of corticosteroids, but this idea has not been investigated and no reports exist of such an interaction in people taking both vitamin A and corticosteroids. People using oral corticosteroids should consult with a doctor to determine whether improved wound healing might outweigh the theoretical risk associated with concomitant vitamin A use.

    Although blood levels of vitamin A appear to increase during dexamethasone therapy—most likely due to mobilization of the vitamin from its stores in the liver—evidence from animal studies has also indicated that corticosteroids can deplete vitamin A from tissues.

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