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Drug Interactions between aminosalicylic acid and Rifadin

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

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Interactions between your drugs

Moderate

rifAMPin aminosalicylic acid

Applies to: Rifadin (rifampin) and aminosalicylic acid

MONITOR: Coadministration with aminosalicylic acid may decrease the serum levels and therapeutic effects of rifampin. The proposed mechanism involves adsorption of rifampin onto an excipient, bentonite, which can be found in some aminosalicylic acid granules. In one study, rifampin serum levels were reduced by more than 50% when coadministered with aminosalicylic acid granules containing bentonite. In other studies, rifampin levels were not affected when administered with aminosalicylic acid tablets that did not contain bentonite as an excipient.

MANAGEMENT: To avoid this interaction, authorities recommend separating the doses by at least 4 hours (AU) or separating doses by not less than 8 hours (UK) or by using an aminosalicylic acid preparation that does not contain bentonite (US; e.g., Paser(R)).

References

  1. Boman G, Hanngren A, Malmborg AS, Borga O, Sjoqvist F (1971) "Drug interaction: decreased serum concentrations of rifampicin when given with P.A.S." Lancet, 1, p. 800
  2. "Product Information. Paser D/R (aminosalicylic acid)." Jacobus Pharmaceutical Company
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  4. Cerner Multum, Inc. "Australian Product Information."
  5. Boman G, Borga O, Hanngren A, Malmborg AS, Sjoqvist F (1970) "Pharmacokinetic interactions between the tuberculostatics rifampicin, para-aminosalicylic acid and isoniazid." Acta Pharmacol Toxicol (Copenh), 28, p. 15
  6. Boman G, Lundgren P, Stjernstrom G (1975) "Mechanism of the inhibitory effect of PAS granules on the absorption of rifampicin: adsorption of rifampicin by an excipient, bentonite." Eur J Clin Pharmacol, 8, p. 293-9
  7. Boman G (1974) "Serum concentration and half-life of rifampicin after simultaneous oral administration of aminosalicylic acid or isoniazid." Eur J Clin Pharmacol, 7, p. 217-25
View all 7 references

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Drug and food interactions

Moderate

rifAMPin food

Applies to: Rifadin (rifampin)

GENERALLY AVOID: Concurrent use of rifampin in patients who ingest alcohol daily may result in an increased incidence of hepatotoxicity. The increase in hepatotoxicity may be due to an additive risk as both alcohol and rifampin are individually associated with this adverse reaction. However, the exact mechanism has not been established.

ADJUST DOSING INTERVAL: Administration with food may reduce oral rifampin absorption, increasing the risk of therapeutic failure or resistance. In a randomized, four-period crossover phase I study of 14 healthy male and female volunteers, the pharmacokinetics of single dose rifampin 600 mg were evaluated under fasting conditions and with a high-fat meal. Researchers observed that administration of rifampin with a high-fat meal reduced rifampin peak plasma concentration (Cmax) by 36%, nearly doubled the time to reach peak plasma concentration (Tmax) but reduced overall exposure (AUC) by only 6%.

MANAGEMENT: The manufacturer of oral forms of rifampin recommends administration on an empty stomach, 30 minutes before or 2 hours after meals. Patients should be encouraged to avoid alcohol or strictly limit their intake. Patients who use alcohol and rifampin concurrently or have a history of alcohol use disorder may require additional monitoring of their liver function during treatment with rifampin.

References

  1. (2022) "Product Information. Rifampin (rifAMPin)." Akorn Inc
  2. (2022) "Product Information. Rifampicin (rifampicin)." Mylan Pharmaceuticals Inc
  3. (2023) "Product Information. Rifadin (rifampicin)." Sanofi
  4. (2024) "Product Information. Rifadin (rifaMPICin)." Sanofi-Aventis Australia Pty Ltd
  5. Peloquin CA, Namdar R, Singleton MD, Nix DE (2024) Pharmacokinetics of rifampin under fasting conditions, with food, and with antacids https://pubmed.ncbi.nlm.nih.gov/9925057/
  6. (2019) "Product Information. Rofact (rifampin)." Bausch Health, Canada Inc.
View all 6 references

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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.

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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.

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