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Drug Interactions between Quinidex Extentabs and riociguat

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

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Interactions between your drugs

Moderate

quiNIDine riociguat

Applies to: Quinidex Extentabs (quinidine) and riociguat

MONITOR: Coadministration with potent inhibitors of CYP450 3A4 or moderate to potent inhibitors of P-glycoprotein (P-gp) or breast cancer resistant protein (BCRP) may increase the plasma concentrations of riociguat, which is partially metabolized by CYP450 3A and also a substrate of the P-gp and BCRP efflux transporters. Increased levels of riociguat may increase the risk for hypotension. When riociguat was administered with ketoconazole, a potent CYP450 3A4 inhibitor that also inhibits P-gp and BCRP, riociguat peak plasma concentration (Cmax) and systemic exposure (AUC) increased by approximately 1.5- and 2.5-fold, respectively. The Cmax and AUC of the active metabolite, M1, which has 1/3 to 1/10 the pharmacologic activity of riociguat, were reduced by approximately 50% and 25%, respectively. Administration with the potent CYP450 3A4 inhibitor clarithromycin increased the AUC of riociguat by about 30%. The Cmax and AUC of M1 were not significantly altered (i.e., <20% increase).

MANAGEMENT: Caution is advised when riociguat is prescribed with potent CYP450 3A4 inhibitors or moderate to potent P-gp or BCRP inhibitors. Patients should be monitored for signs and symptoms of hypotension, and the dosage of riociguat adjusted if necessary.

References (4)
  1. (2023) "Product Information. Adempas (riociguat)." Merck Sharp & Dohme (UK) Ltd
  2. (2022) "Product Information. Adempas (riociguat)." Bayer Australia Limited
  3. (2024) "Product Information. Sandoz Riociguat (riociguat)." Sandoz Canada Incorporated
  4. (2024) "Product Information. Adempas (riociguat)." Bayer Pharmaceutical Inc

Drug and food interactions

Moderate

quiNIDine food

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

riociguat food

Applies to: riociguat

ADJUST DOSE: Smoking may decrease the plasma concentrations of riociguat. The proposed mechanism is induction of the CYP450 1A1-mediated metabolism of riociguat by polycyclic aromatic hydrocarbons present in cigarette smoke. CYP450 1A1 is responsible for the formation of the major active metabolite, M1, which has just 1/3 to 1/10 the pharmacologic activity of riociguat. According to the product labeling, plasma concentrations of riociguat are reduced by 50% to 60% in smokers compared to nonsmokers.

MANAGEMENT: Patients should be advised to stop smoking. Riociguat dosages higher than 2.5 mg three times a day may be considered in cigarette smokers, if tolerated, to match the exposure seen in nonsmoking patients. However, safety and effectiveness of higher dosages have not been established. A dosage reduction should be considered in patients who stop smoking during treatment with riociguat. The tablet form of riociguat can generally be taken with or without food. Some authorities recommend not to switch between fed and fasted riociguat intake because of increased peak plasma levels of riociguat in the fasting compared to the fed state.

References (3)
  1. (2013) "Product Information. Adempas (riociguat)." Bayer Pharmaceutical Inc
  2. (2023) "Product Information. Adempas (riociguat)." Merck Sharp & Dohme (UK) Ltd
  3. (2014) "Product Information. Adempas (riociguat)." Bayer Australia Limited

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

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