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Drug Interactions between Paxlovid and pretomanid

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

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Interactions between your drugs

Moderate

pretomanid nirmatrelvir

Applies to: pretomanid and Paxlovid (nirmatrelvir / ritonavir)

MONITOR: Coadministration with pretomanid may increase the plasma concentrations and the risk of adverse effects of drugs that are substrates of breast cancer resistance protein (BCRP), organic anion-transporting polypeptide (OATP1B3), and/or P-glycoprotein (P-gp). The proposed mechanism, based on in vitro data, is decreased clearance due to pretomanid-mediated inhibition of BCRP, OATP1B3, and/or P-gp. The clinical significance is unknown as data are limited and conflicting.

MANAGEMENT: Until more information is available, the manufacturers of pretomanid recommend that clinicians should be aware of the potential for enhanced pharmacologic effects with drugs that are substrates of BCRP, OATP1B3, and/or Pg-p, particularly those with a narrow therapeutic range, when pretomanid is coadministered. Dosage adjustments as well as clinical and laboratory monitoring of the BCRP, OATP1B3, and/or P-gp substrate drug should be considered whenever pretomanid is added to or withdrawn from therapy with these drugs. Patients should be monitored for the development of adverse effects.

References (3)
  1. (2019) "Product Information. Pretomanid (pretomanid)." The Global Alliance for TB Drug Development
  2. (2024) "Product Information. Dovprela (pretomanid)." Imported (Italy)
  3. Center for Drug Evaluation and Research (2025) Center for drug evaluation and research. Application number: 212862Orig1s000. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2019/212862Orig1s000MultidisciplineR.pdf
Minor

ritonavir pretomanid

Applies to: Paxlovid (nirmatrelvir / ritonavir) and pretomanid

Coadministration with lopinavir/ritonavir may reduce the plasma concentrations of pretomanid. The mechanism of this interaction is unknown, but may involve minimal induction (approximately 20%) of CYP450 3A metabolism. In a study including 52 healthy adults who were administered multiple-dose pretomanid with multiple-dose ritonavir-boosted-lopinavir, the mean systemic exposure (AUC0-24h) and mean peak plasma concentration (Cmax) of pretomanid decreased by 17% and 13%, respectively. Mean AUC and Cmax of lopinavir were decreased by 14% and 17%, respectively. These changes were statistically, but not clinically, significant. Pretomanid and lopinavir/ritonavir may be coadministered without any dosage adjustments.

References (2)
  1. (2019) "Product Information. Pretomanid (pretomanid)." The Global Alliance for TB Drug Development
  2. (2024) "Product Information. Dovprela (pretomanid)." Imported (Italy)

Drug and food interactions

Moderate

ritonavir food

Applies to: Paxlovid (nirmatrelvir / ritonavir)

ADJUST DOSING INTERVAL: Administration with food may modestly affect the bioavailability of ritonavir from the various available formulations. When the oral solution was given under nonfasting conditions, peak ritonavir concentrations decreased 23% and the extent of absorption decreased 7% relative to fasting conditions. Dilution of the oral solution (within one hour of dosing) with 240 mL of chocolate milk or a nutritional supplement (Advera or Ensure) did not significantly affect the extent and rate of ritonavir absorption. When a single 100 mg dose of the tablet was administered with a high-fat meal (907 kcal; 52% fat, 15% protein, 33% carbohydrates), approximately 20% decreases in mean peak concentration (Cmax) and systemic exposure (AUC) were observed relative to administration after fasting. Similar decreases in Cmax and AUC were reported when the tablet was administered with a moderate-fat meal. In contrast, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate) relative to fasting.

MANAGEMENT: Ritonavir should be taken with meals to enhance gastrointestinal tolerability.

References (1)
  1. (2001) "Product Information. Norvir (ritonavir)." Abbott Pharmaceutical
Moderate

pretomanid food

Applies to: pretomanid

GENERALLY AVOID: Coadministration with alcohol may increase the risk of hepatotoxicity associated with the use of combination drug regimens that include pretomanid.

ADJUST DOSING INTERVAL: Food enhances the oral bioavailability of pretomanid. The mechanism has not been reported. Compared with the fasted state, oral administration of pretomanid with a high-fat, high-calorie meal (approximately 150, 250, and 500 to 600 calories from protein, carbohydrate, and fat, respectively) increased mean systemic exposure (AUC) and peak plasma concentration (Cmax) of pretomanid by 88% and 76%, respectively.

MANAGEMENT: Patients should avoid alcohol use during treatment with pretomanid. In addition, to ensure maximal oral absorption, pretomanid should be administered with food. Tablets should be swallowed whole.

References (1)
  1. (2019) "Product Information. Pretomanid (pretomanid)." The Global Alliance for TB Drug Development

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.


Report options

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.