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Drug Interactions between ampicillin and bismuth subcitrate potassium / metronidazole / tetracycline

This report displays the potential drug interactions for the following 2 drugs:

  • ampicillin
  • bismuth subcitrate potassium/metronidazole/tetracycline

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Interactions between your drugs


ampicillin tetracycline

Applies to: ampicillin and bismuth subcitrate potassium / metronidazole / tetracycline

GENERALLY AVOID: Tetracyclines may reduce the effect of penicillins by inhibiting cellular protein synthesis which is necessary for cell wall synthesis inhibition by penicillins. Antagonism is more likely when low doses of either agent are administered. Therapeutic failure may result.

MANAGEMENT: This combination should be avoided if possible.


  1. "Product Information. Seysara (sarecycline)." Allergan Inc, Irvine, CA.
  2. "Product Information. Declomycin (demeclocycline)." Lederle Laboratories, Wayne, NJ.
  3. Jawetz E "Synergism and antagonism among antimicrobial drugs: a personal perspective." West J Med 123 (1975): 87-91
  4. Lepper MH, Dowling HF "Treatment of pneumococcic meningitis with penicillin compared with penicillin plus aureomycin." Arch Intern Med 88 (1951): 489-94
  5. Gunnison JB, Coleman VR, Jawetz E "Interference of aureomycin and of terramycin with action of penicillin in vitro." Proc Soc Exp Biol Med 75 (1950): 549-52
  6. Olsson RA, Kirby JC, Romansky MJ "Pneumococcal meningitis in the adult." Ann Intern Med 55 (1961): 545-9
View all 6 references

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tetracycline bismuth subcitrate potassium

Applies to: bismuth subcitrate potassium / metronidazole / tetracycline and bismuth subcitrate potassium / metronidazole / tetracycline

ADJUST DOSING INTERVAL: Administration of a bismuth-containing preparation within two to three hours of a tetracycline may significantly decrease serum tetracycline concentrations. Data are available for tetracycline and doxycycline. The proposed mechanism is chelation of tetracycline by bismuth.

MANAGEMENT: Administration of a tetracycline and bismuth-containing preparation should be separated by two to three hours. Patients should be monitored for diminished tetracycline efficacy.


  1. Albert KS, Welch RD, DeSante KA, DiSanto AR "Decreased tetracycline bioavailability caused by a bismuth subsalicylate antidiarrheal mixture." J Pharm Sci 68 (1979): 586-8
  2. Ericsson CD, Feldman S, Pickering LK, Cleary TG "Influence of subsalicylate bismuth on absorption of doxycycline." JAMA 247 (1982): 2266-7
  3. "Product Information. Seysara (sarecycline)." Allergan Inc, Irvine, CA.
  4. "Product Information. Nuzyra (omadacycline)." Paratek Pharmaceuticals, Inc., Boston, MA.
View all 4 references

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Drug and food interactions


metroNIDAZOLE food

Applies to: bismuth subcitrate potassium / metronidazole / tetracycline

CONTRAINDICATED: Use of alcohol or products containing alcohol during nitroimidazole therapy may result in a disulfiram-like reaction in some patients. There have been a few case reports involving metronidazole, although data overall are not convincing. The presumed mechanism is inhibition of aldehyde dehydrogenase (ALDH) by metronidazole in a manner similar to disulfiram. Following ingestion of alcohol, inhibition of ALDH results in increased concentrations of acetaldehyde, the accumulation of which can produce an unpleasant physiologic response referred to as the 'disulfiram reaction'. Symptoms include flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion. Severe reactions may result in respiratory depression, cardiovascular collapse, arrhythmia, myocardial infarction, acute congestive heart failure, unconsciousness, convulsions, and death. However, some investigators have questioned the disulfiram-like properties of metronidazole. One study found neither elevations in blood acetaldehyde nor objective or subjective signs of a disulfiram-like reaction to ethanol in six subjects treated with metronidazole (200 mg three times a day for 5 days) compared to six subjects who received placebo.

MANAGEMENT: Because clear evidence is lacking concerning the safety of ethanol use during nitroimidazole therapy, patients should be apprised of the potential for interaction. Consumption of alcoholic beverages and products containing propylene glycol is specifically contraindicated during and for at least 3 days after completion of metronidazole and benznidazole therapy according to their product labeling.


  1. Giannini AJ, DeFrance DT "Metronidazole and alcohol: potential for combinative abuse." J Toxicol Clin Toxicol 20 (1983): 509-15
  2. Edwards DL, Fink PC, Van Dyke PO "Disulfiram-like reaction associated with intravenous trimethoprim-sulfamethoxazole and metronidazole." Clin Pharm 5 (1986): 999-1000
  3. Krulewitch CJ "An unexpected adverse drug effect." J Midwifery Womens Health 48 (2003): 67-8
  4. Harries DP, Teale KF, Sunderland G "Metronidazole and alcohol: potential problems." Scott Med J 35 (1990): 179-80
  5. Visapaa JP, Tillonen JS, Kaihovaara PS, Salaspuro MP "Lack of disulfiram-like reaction with metronidazole and ethanol." Ann Pharmacother 36 (2002): 971-4
  6. "Product Information. Benznidazole (benznidazole)." Everett Laboratories Inc, West Orange, NJ.
  7. Williams CS, Woodcock KR "Do ethanol and metronidazole interact to produce a disulfiram-like reaction?." Ann Pharmacother 34 (2000): 255-7
  8. Alexander I "Alcohol-antabuse syndrome in patients receiving metronidazole during gynaecological treatment." Br J Clin Pract 39 (1985): 292-3
  9. "Product Information. Flagyl (metronidazole)." Searle, Skokie, IL.
View all 9 references

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ampicillin food

Applies to: ampicillin

ADJUST DOSING INTERVAL: Certain penicillins may exhibit reduced gastrointestinal absorption in the presence of food. The therapeutic effect of the antimicrobial may be reduced.

MANAGEMENT: The interacting penicillin should be administered one hour before or two hours after meals. Penicillin V and amoxicillin are not affected by food and may be given without regard to meals.


  1. McCarthy CG, Finland M "Absorption and excretion of four penicillins." N Engl J Med 263 (1960): 315-26
  2. Neu HC "Antimicrobial activity and human pharmacology of amoxicillin." J Infect Dis 129 (1974): s123-31
  3. Klein JO, Sabath LD, Finland M "Laboratory studies on oxacillin. I: in vitro activity against staphylococci and some other bacterial pathogens. II: absorption and urinary excretion in normal young." Am J Med Sci 245 (1963): 399-411
  4. Cronk GA, Wheatley WB, Fellers GF, Albright H "The relationship of food intake to the absorption of potassium alpha-phenoxyethyl penicillin and potassium phenoxymethyl penicillin from the gastrointestinal tract." Am J Med Sci 240 (1960): 219-25
  5. Neuvonen PJ, Elonen E, Pentikainen PJ "Comparative effect of food on absorption of ampicillin and pivampicillin." J Int Med Res 5 (1977): 71-6
  6. Welling PG, Huang H, Koch PA, Madsen PO "Bioavailability of ampicillin and amoxicillin in fasted and nonfasted subjects." J Pharm Sci 66 (1977): 549-52
View all 6 references

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tetracycline food

Applies to: bismuth subcitrate potassium / metronidazole / tetracycline

ADJUST DOSING INTERVAL: Administration with food, particularly dairy products, significantly reduces tetracycline absorption. The calcium content of these foods forms nonabsorbable chelates with tetracycline.

MANAGEMENT: Tetracycline should be administered one hour before or two hours after meals.


  1. "Product Information. Achromycin (tetracycline)." Lederle Laboratories, Wayne, NJ.
  2. "Product Information. Declomycin (demeclocycline)." Lederle Laboratories, Wayne, NJ.

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.