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Drug Interactions between Priftin and Quinora

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

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Interactions between your drugs

Moderate

quiNIDine rifapentine

Applies to: Quinora (quinidine) and Priftin (rifapentine)

MONITOR: Rifamycins may increase the hepatic metabolism of quinidine by inducing CYP450 3A4 isoenzymes. Serum quinidine levels and quinidine effect may be decreased.

MANAGEMENT: Frequent monitoring of quinidine levels and arrhythmia control is recommended. Increased quinidine dosage may be needed. When a rifamycin is discontinued, enzyme induction and increased hepatic metabolism of quinidine may persist for one week. Patients should be advised to notify their physician if they experience an increase in irregular heartbeats.

References

  1. Twum-Barima Y, Carruthers SG "Quinidine-rifampin interaction." N Engl J Med 304 (1981): 1466-9
  2. Venkatesan K "Pharmacokinetic drug interactions with rifampicin." Clin Pharmacokinet 22 (1992): 47-65
  3. Borcherding SM, Baciewicz AM, Self TH "Update on rifampin drug interactions." Arch Intern Med 152 (1992): 711-6
  4. Schwartz A, Brown JR "Quinidine-rifampin interaction." Am Heart J 107 (1984): 789-90
  5. Bussey HI, Merritt GJ, Hill EG "The influence of rifampin on quinidine and digoxin." Arch Intern Med 144 (1984): 1021-3
  6. Reed R, Schwartz H "Phenytoin-theophylline-quinidine interactions." N Engl J Med 308 (1983): 724-5
  7. Ahmad D, Mathur P, Ahuja S, Henderson R, Carruthers G "Rifampicin-quinidine interaction." Br J Dis Chest 73 (1979): 409-11
  8. Strayhorn VA, Baciewicz AM, Self TH "Update on rifampin drug interactions, III." Arch Intern Med 157 (1997): 2453-8
View all 8 references

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Drug and food interactions

Moderate

quiNIDine food

Applies to: Quinora (quinidine)

GENERALLY AVOID: In a small, randomized, crossover study, the administration of quinidine with grapefruit juice (compared to water) to healthy volunteers significantly prolonged the time to reach peak plasma quinidine concentrations and decreased the plasma concentrations of its major metabolite, 3-hydroxyquinidine. These changes were associated pharmacodynamically with both a delay and a reduction in the maximal effect on QTc interval. The proposed mechanism is delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Given the drug's narrow therapeutic index, patients receiving quinidine therapy should avoid the consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels.

References

  1. Ace LN, Jaffe JM, Kunka RL "Effect of food and an antacid on quinidine bioavailability." Biopharm Drug Dispos 4 (1983): 183-90
  2. Min DI, Ku YM, Geraets DR, Lee HC "Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers." J Clin Pharmacol 36 (1996): 469-76
  3. Ha HR, Chen J, Leuenberger PM, Freiburghaus AU, Follah F "In vitro inhibition of midazolam and quinidine metabolism by flavonoids." Eur J Clin Pharmacol 48 (1995): 367-71
  4. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther 68 (2000): 468-77
View all 4 references

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Moderate

rifapentine food

Applies to: Priftin (rifapentine)

ADJUST DOSING INTERVAL: Administration with food may increase the oral bioavailability of rifapentine and reduce the incidence of gastrointestinal adverse events. Administration with a high fat meal typically increases rifapentine's maximum concentration (Cmax) and systemic exposure (AUC) by approximately 40% to 50% over that observed when rifapentine is administered under fasting conditions. Rifapentine is often prescribed in combination with isoniazid. When single doses of rifapentine (900 mg) and isoniazid (900 mg) were administered with a low fat, high carbohydrate breakfast, the Cmax and AUC of rifapentine increased by 47% and 51%, respectively. On the other hand, isoniazid's Cmax and AUC decreased by 46% and 23%, respectively.

MANAGEMENT: Products containing oral rifapentine as the sole ingredient recommend administration with a meal to increase bioavailability and reduce the occurrence of gastrointestinal upset, nausea, and/or vomiting. Consultation of product labeling for combination products and/or relevant guidelines may be helpful if rifapentine is combined with a medication that is typically taken on an empty stomach.

References

  1. "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India) 2 (2021):
  2. "Product Information. Priftin (rifapentine)." sanofi-aventis (2021):

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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.

See also

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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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