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Drug Interactions between amoxicillin / clarithromycin / omeprazole and Gilotrif

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

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Interactions between your drugs

Moderate

clarithromycin afatinib

Applies to: amoxicillin / clarithromycin / omeprazole and Gilotrif (afatinib)

ADJUST DOSE: Coadministration with inhibitors of P-glycoprotein (P-gp) may increase the plasma concentrations of afatinib, which is a substrate of the efflux transporter. In study subjects, oral administration of the P-gp inhibitor ritonavir (200 mg twice daily) one hour before afatinib dosing resulted in a 48% increase in afatinib systemic exposure. There was no change in afatinib exposure when ritonavir was administered simultaneously with, or 6 hours after, the afatinib dose.

MANAGEMENT: Caution is advised if afatinib is used in combination with P-gp inhibitors. Patients should be monitored for potentially increased adverse effects such as diarrhea, which may lead to dehydration with or without renal impairment; cutaneous reactions including rash, erythema, and bullous, blistering, or exfoliating lesions; interstitial lung disease such as lung infiltration, pneumonitis, acute respiratory distress syndrome, and allergic alveolitis; hepatotoxicity, which may be life-threatening or fatal; keratitis characterized by acute or worsening eye inflammation, lacrimation, light sensitivity, blurred vision, eye pain, red eye, and/or ulceration; and left ventricular dysfunction. The manufacturer recommends reducing the daily dose of afatinib by 10 mg if not tolerated. The previous dose may be resumed after discontinuation of the P-gp inhibitor as tolerated.

References

  1. "Product Information. Gilotrif (afatinib)." Boehringer Ingelheim (2013):

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Minor

amoxicillin clarithromycin

Applies to: amoxicillin / clarithromycin / omeprazole and amoxicillin / clarithromycin / omeprazole

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.

References

  1. Strom J "Penicillin and erythromycin singly and in combination in scarlatina therapy and the interference between them." Antibiot Chemother 11 (1961): 694-7
  2. Cohn JR, Jungkind DL, Baker JS "In vitro antagonism by erythromycin of the bactericidal action of antimicrobial agents against common respiratory pathogens." Antimicrob Agents Chemother 18 (1980): 872-6
  3. Penn RL, Ward TT, Steigbigel RT "Effects of erythromycin in combination with penicillin, ampicillin, or gentamicin on the growth of listeria monocytogenes." Antimicrob Agents Chemother 22 (1982): 289-94

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Minor

clarithromycin omeprazole

Applies to: amoxicillin / clarithromycin / omeprazole and amoxicillin / clarithromycin / omeprazole

Clarithromycin may increase and prolong the omeprazole plasma concentration. The mechanism may be related to clarithromycin inhibition of hepatic cytochrome P450 enzymes responsible for omeprazole metabolism. Coadministration of omeprazole may result in an increase in clarithromycin and 14-(R)-hydroxyclarithromycin plasma concentrations. These increases may be due to the effect of omeprazole on gastric pH.

References

  1. Zhou Q, Yamamoto I, Fukuda T, Ohno M, Sumida A, Azuma J "CYP2C19 genotypes and omeprazole metabolism after single and repeated dosing when combined with clarithromycin." Eur J Clin Pharmacol 55 (1999): 43-7
  2. Gustavson LE, Kaiser JF, Edmonds AL, Locke CS, DeBartolo ML, Schneck DW "Effect of omeprazole on concentrations of clarithromycin in plasma and gastric tissue at steady state." Antimicrob Agents Chemother 39 (1995): 2078-83
  3. Furuta T, Ohashi K, Kobayashi K, Iida I, Yoshida H, Shirai N, Takashima M, Kosuge K, Hanai H, Chiba K, Ishizaki T, Kaneko E "Effects of clarithromycin on the metabolism of omeprazole in relation to CYP2C19 genotype status in humans." Clin Pharmacol Ther 66 (1999): 265-74

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Drug and food interactions

Moderate

afatinib food

Applies to: Gilotrif (afatinib)

ADJUST DOSING INTERVAL: Food may reduce the oral bioavailability of afatinib. According to the product labeling, administration of afatinib with a high-fat meal decreased peak plasma concentration (Cmax) by 50% and systemic exposure (AUC) by 39% compared to administration in the fasted state.

MANAGEMENT: Afatinib should be taken at least 1 hour before or 2 hours after a meal.

References

  1. "Product Information. Gilotrif (afatinib)." Boehringer Ingelheim (2013):

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Minor

clarithromycin food

Applies to: amoxicillin / clarithromycin / omeprazole

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.

References

  1. Cheng KL, Nafziger AN, Peloquin CA, Amsden GW "Effect of grapefruit juice on clarithromycin pharmacokinetics." Antimicrob Agents Chemother 42 (1998): 927-9

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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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