Drug Interaction Report
2 potential interactions and/or warnings found for the following 2 drugs:
- atovaquone
- Noxafil (posaconazole)
Interactions between your drugs
No drug ⬌ drug interactions were found between the drugs in your list. However, this does not necessarily mean no drug interactions exist. Always consult your healthcare provider.
Drug and food interactions
atovaquone food
Applies to: atovaquone
ADJUST DOSING INTERVAL: Food, particularly high-fat food, significantly enhances the oral absorption and bioavailability of atovaquone. In 16 healthy volunteers, administration of a single 750 mg dose of atovaquone suspension following a standard breakfast (23 g fat: 610 kCal) resulted in an approximately 3.4-fold increase in the mean peak plasma concentration (Cmax) and a 2.5-fold increase in the mean area under the plasma concentration-time curve (AUC) of atovaquone compared to administration following an overnight fast. In a study consisting of 19 HIV-infected volunteers receiving atovaquone suspension 500 mg/day, Cmax and AUC of atovaquone increased by 72% and 66%, respectively, in the fed state relative to the fasting state.
MANAGEMENT: To ensure maximal oral absorption, atovaquone products (suspension, tablet, or in combination with proguanil) should be administered with a meal or milky drink, or enteral nutrition at the same time(s) each day. Because plasma atovaquone concentrations have been shown to correlate with the likelihood of successful treatment and in some cases, survival, alternative therapies may be appropriate for patients who have difficulty taking atovaquone with food.
References
- (2001) "Product Information. Mepron (atovaquone)." Glaxo Wellcome
- (2001) "Product Information. Malarone (atovaquone-proguanil)." Glaxo Wellcome
- Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT (2009) "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm, 66, p. 1438-67
posaconazole food
Applies to: Noxafil (posaconazole)
ADJUST DOSING INTERVAL: Food significantly increases the absorption of posaconazole from the oral suspension but only modestly from the delayed-release tablet. Following single-dose administration, posaconazole mean peak plasma concentration (Cmax) and systemic exposure (AUC) are approximately 2.5 to 3 times higher when the oral suspension is given with a nonfat meal or a nutritional supplement (14 grams of fat) than when given under fasting conditions, and approximately 3.5 to 4 times higher when given during or 20 minutes after a high-fat meal (50 grams of fat) than under fasting conditions. Acidic beverages may also increase posaconazole absorption. In 12 healthy volunteers, administration of a single 400 mg dose of posaconazole suspension with 12 ounces of ginger ale increased posaconazole Cmax by 92% and AUC by 70% compared to administration after fasting. In contrast, the Cmax and AUC of posaconazole increased by just 16% and 51%, respectively, when posaconazole tablets were given as a single 300 mg dose to healthy volunteers after a high-fat meal relative to a fasted state.
GENERALLY AVOID Concomitant use of alcohol and posaconazole administered in the form of delayed-release oral suspension may lead to a faster release of posaconazole. An in vitro dissolution study determined a potential for alcohol-induced dose-dumping with the delayed-release oral suspension of posaconazole.
MONITOR: In 5 study subjects, posaconazole Cmax decreased by 27% to 53% and AUC decreased by 33% to 51% when the oral suspension was administered via a nasogastric tube as opposed to orally.
MANAGEMENT: Posaconazole tablets should be taken with food, whereas posaconazole oral suspension should be administered during or immediately (i.e., within 20 minutes) following a full meal to enhance bioavailability. Patients who cannot eat a full meal should take the suspension with a liquid nutritional supplement or an acidic carbonated beverage such as ginger ale. In patients who cannot eat a full meal or tolerate an oral nutritional supplement or an acidic carbonated beverage and who do not have the option of taking another formulation of posaconazole, alternative antifungal therapy should be considered; otherwise, monitor patients closely for breakthrough fungal infections. Patients receiving posaconazole via a nasogastric tube should also be closely monitored due to increased risk of treatment failure associated with lower plasma exposure. Administration of alcohol with posaconazole from the delayed-release oral suspension formulation is not recommended.
References
- (2006) "Product Information. Noxafil (posaconazole)." Schering-Plough Corporation
- Sansone-Parsons A, Krishna G, Calzetta A, et al. (2006) "Effect of a nutritional supplement on posaconazole pharmacokinetics following oral administration to healthy volunteers." Antimicrob Agents Chemother, 50, p. 1881-3
- Krishna G, Moton A, Ma L, Malavade D, Medlock M, McLeod J (2008) "Effect of gastric pH, dosing regimen and prandial state, food and meal timing relative to dose, and gastro-intestinal motility on absorption and pharmacokinetics of the antifungal posaconazole." 18th European Congress of Clinical Microbiology and Infectious Diseases, April, p. 20
- Walravens J, Brouwers J, Spriet I, Tack J, Annaert P, Augustijns P (2011) "Effect of pH and Comedication on Gastrointestinal Absorption of Posaconazole: Monitoring of Intraluminal and Plasma Drug Concentrations." Clin Pharmacokinet, 50, p. 725-34
Therapeutic duplication warnings
No duplication 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
| Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
| Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
| 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. | |
| No interaction information available. |
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Further information
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