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Drug Interactions between Junel 1/20 and Omnicef Omni-Pac

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

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Moderate

ethinyl estradiol cefdinir

Applies to: Junel 1 / 20 (ethinyl estradiol / norethindrone) and Omnicef Omni-Pac (cefdinir)

ADDITIONAL CONTRACEPTION RECOMMENDED: The effectiveness of estrogen-containing oral contraceptives may be impaired by concomitant treatment with antimicrobial agents. However, the risk appears to be small, and supportive data are primarily limited to anecdotal evidence from case reports and findings from uncontrolled or poorly controlled studies. Most antimicrobials, with the exception of the rifamycins and possibly griseofulvin, do not induce hepatic enzymes and have not been shown to significantly increase the clearance of oral contraceptive estrogens. Some investigators believe that antimicrobials interfere with the enterohepatic recirculation of estrogens by decreasing bacterial hydrolytic enzymes in the gastrointestinal tract that are responsible for regenerating parent estrogen molecules following first-pass metabolism. It is possible that a small number of women may be more susceptible to contraceptive failure and, consequently, are more sensitive to the effects of antimicrobials on estrogen disposition in vivo, but risk factors or genetic predispositions have yet to be identified.

MANAGEMENT: Until further data are available, women using oral contraceptives should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant antimicrobial therapy. Alternative or additional methods of birth control should be considered during and for at least one week beyond the last dose of short-term antimicrobial therapy, and for at least the initial weeks of long-term antimicrobial therapy when risk may be the greatest.

ADJUST DOSING INTERVAL: The non-hormonal placebo pills included in some oral contraceptive preparations may contain iron, usually ferrous fumarate. Concomitant administration of these iron pills may significantly decrease the gastrointestinal absorption of antibiotics such as cefdinir. The proposed mechanism is chelation of cefdinir by the iron cation, forming a complex that is poorly absorbed from the gastrointestinal tract. According to product labeling, concomitant administration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron (as ferrous sulfate) or vitamins supplemented with 10 mg of elemental iron resulted in a reduction of cefdinir absorption by 80% and 31%, respectively.

MANAGEMENT: To minimize potential interaction with iron, the product labeling recommends that cefdinir be taken at least 2 hours before or 2 hours after administration of iron-containing products.

References

  1. Friedman CI, Huneke AL, Kim MH, Powell J "The effect of ampicillin on oral contraceptive effectiveness." Obstet Gynecol 55 (1980): 33-7
  2. Back DJ, Breckenridge AM, MacIver M, et al. "The effects of ampicillin on oral contraceptive steroids in women." Br J Clin Pharmacol 14 (1982): 43-8
  3. Neely JL, Abate M, Swinker M, D'Angio R "The effect of doxycycline on serum levels of ethinyl estradiol, norethindrone, and endogenous progesterone." Obstet Gynecol 77 (1991): 416-20
  4. Joshi JV, Joshi UM, Sankholi GM, et al. "A study of interaction of low-dose combination oral contraceptive with ampicillin and metronidazole." Contraception 22 (1980): 643-52
  5. Baciewicz AM "Oral contraceptive drug interactions." Ther Drug Monit 7 (1985): 26-35
  6. Bint AJ, Burtt I "Adverse antibiotic drug interactions." Drugs 20 (1980): 57-68
  7. Dossetor J "Drug interactions with oral contraceptives." Br Med J 4 (1975): 467-8
  8. DeSano EA, Hurley SC "Possible interactions of antihistamines and antibiotics with oral contraceptive effectiveness." Fertil Steril 37 (1982): 853-4
  9. Szoka PR, Edgren RA "Drug interactions with oral contraceptives: compilation and analysis of an adverse experience report database." Fertil Steril 49(5 Suppl) (1988): s31-8
  10. Barnett ML "Inhibition of oral contraceptive effectiveness by concurrent antibiotic administration." J Periodontol 56 (1985): 18-20
  11. London BM, Lookingbill DP "Frequency of pregnancy in acne patients taking oral antibiotics and oral contraceptives." Arch Dermatol 130 (1994): 392-3
  12. Bacon JF, Shenfield GM "Pregnancy attributable to interaction between tetracycline and oral contraceptives." Br Med J 280 (1980): 293
  13. Fazio A "Oral contraceptive drug interactions: important considerations." South Med J 84 (1991): 997-1002
  14. Back DJ, Orme ML "Pharmacokinetic drug interactions with oral contraceptives." Clin Pharmacokinet 18 (1990): 472-84
  15. Back DJ, Tjia J, Martin C, Millar E, Mant T, Morrison P, Orme M "The lack of interaction between temafloxacin and combined oral contraceptive steroids." Contraception 43 (1991): 317-23
  16. Orme ML, Back DJ "Interactions between oral contraceptive steroids and broad-spectrum antibiotics." Clin Exp Dermatol 11 (1986): 327-31
  17. Wermeling DP, Chandler MH, Sides GD, Collins D, Muse KN "Dirithromycin increases ethinyl estradiol clearance without allowing ovulation." Obstet Gynecol 86 (1995): 78-84
  18. Silber TJ "Apparent oral contraceptive failure associated with antibiotic administration." J Adolesc Health Care 4 (1983): 287-9
  19. Bollen M "Use of antibiotics when taking the oral contraceptive pill." Aust Fam Physician 24 (1995): 928-9
  20. Kleier DJ, Tucker JE "Oral contraceptive failure secondary to dentally prescribed drugs: fact or fiction?" J Colo Dent Assoc 66 (1987): 5-6
  21. Ueno K, Tanaka K, Tsujimura K, Morishima Y, Iwashige H, Yamazaki K, Nakata I "Impairment of cefdinir absorption by iron ion." Clin Pharmacol Ther 54 (1993): 473-5
  22. "Product Information. Omnicef (cefdinir)." Parke-Davis PROD (2001):
  23. Back DJ, Breckenridge AM, Crawford FE, MacIver M, Orne ML, Rowe PH "Interindividual variation and drug interactions with hormonal steroid contraceptives." Drugs 21 (1981): 46-61
  24. Helms SE, Bredle DL, Zajic J, Jarjoura D, Brodell RT, Krishnarao I "Oral contraceptive failure rates and oral antibiotics." J Am Acad Dermatol 36 (1997): 705-10
  25. Weisberg E "Interactions between oral contraceptives and antifungals antibacterials - Is contraceptive failure the result?." Clin Pharmacokinet 36 (1999): 309-13
  26. Burroughs KE, Chambliss ML "Antibiotics and oral contraceptive failure." Arch Fam 9 (2000): 81-2
  27. Weaver K, Glasier A "Interaction between broad-spectrum antibiotics and the combined oral contraceptive pill: a literature review." Contraception 59 (1999): 71-8
  28. King VJ "OC failure rates and oral antibiotics." J Fam Pract 45 (1997): 104-5
  29. Zachariassen RD "Loss of oral contraceptive efficacy by concurrent antibiotic administration." Women Health 22 (1994): 17-26
  30. Dickinson BD, Altman RD, Nielsen NH, Sterling ML "Drug interactions between oral contraceptives and antibiotics." Obstet Gynecol 98(5 Pt 1) (2001): 853-60
  31. Archer JS, Archer DF "Oral contraceptive efficacy and antibiotic interaction: A myth debunked." J Am Acad Dermatol 46 (2002): 917-23
  32. Orme M, Back DJ "Oral contraceptive steroids--pharmacological issues of interest to the prescribing physician." Adv Contracept 7 (1991): 325-31
  33. DeRossi SS, Hersh EV "Antibiotics and oral contraceptives." Dent Clin North Am 46 (2002): 653-64
  34. "FFPRHC Guidance (April 2005). Drug interactions with hormonal contraception." J Fam Plann Reprod Health Care 31 (2005): 139-51
  35. Bauer KL, Wolf D, Patel M, Vinson DC "Clinical inquiries. Do antibiotics interfere with the efficacy of oral contraceptives?" J Fam Pract 54 (2005): 1079-80
  36. Back DJ, Grimmer SF, Orme ML, Proudlove D, Mann RD, Breckenridge AM "Evaluation of Committee on Safety of Medicines yellow card reports on oral contraceptive-drug interactions with anticonvulsants and antibiotics." Br J Clin Pharmacol 25 (1988): 527-32
View all 36 references

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Drug and food interactions

Moderate

norethindrone food

Applies to: Junel 1 / 20 (ethinyl estradiol / norethindrone)

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4. Grapefruit and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact with these drugs.

References

  1. Edgar B, Bailey D, Bergstrand R, et al. "Acute effects of drinking grapefruit juice on the pharmacokinetics and dynamics on felodipine and its potential clinical relevance." Eur J Clin Pharmacol 42 (1992): 313-7
  2. Jonkman JH, Sollie FA, Sauter R, Steinijans VW "The influence of caffeine on the steady-state pharmacokinetics of theophylline." Clin Pharmacol Ther 49 (1991): 248-55
  3. Bailey DG, Arnold JM, Munoz C, Spence JD "Grapefruit juice--felodipine interaction: mechanism, predictability, and effect of naringin." Clin Pharmacol Ther 53 (1993): 637-42
  4. Bailey DG, Arnold JMO, Spence JD "Grapefruit juice and drugs - how significant is the interaction." Clin Pharmacokinet 26 (1994): 91-8
  5. Sigusch H, Hippius M, Henschel L, Kaufmann K, Hoffmann A "Influence of grapefruit juice on the pharmacokinetics of a slow release nifedipine formulation." Pharmazie 49 (1994): 522-4
  6. Bailey DG, Arnold JM, Strong HA, Munoz C, Spence JD "Effect of grapefruit juice and naringin on nisoldipine pharmacokinetics." Clin Pharmacol Ther 54 (1993): 589-94
  7. Yamreudeewong W, Henann NE, Fazio A, Lower DL, Cassidy TG "Drug-food interactions in clinical practice." J Fam Pract 40 (1995): 376-84
  8. "Grapefruit juice interactions with drugs." Med Lett Drugs Ther 37 (1995): 73-4
  9. Hukkinen SK, Varhe A, Olkkola KT, Neuvonen PJ "Plasma concentrations of triazolam are increased by concomitant ingestion of grapefruit juice." Clin Pharmacol Ther 58 (1995): 127-31
  10. 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
  11. Majeed A, Kareem A "Effect of grapefruit juice on cyclosporine pharmacokinetics." Pediatr Nephrol 10 (1996): 395
  12. Clifford CP, Adams DA, Murray S, Taylor GW, Wilkins MR, Boobis AR, Davies DS "Pharmacokinetic and cardiac effects of terfenadine after inhibition of its metabolism by grapefruit juice." Br J Clin Pharmacol 42 (1996): p662
  13. Josefsson M, Zackrisson AL, Ahlner J "Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers." Eur J Clin Pharmacol 51 (1996): 189-93
  14. Kantola T, Kivisto KT, Neuvonen PJ "Grapefruit juice greatly increases serum concentrations of lovastatin and lovastatin acid." Clin Pharmacol Ther 63 (1998): 397-402
  15. Ozdemir M, Aktan Y, Boydag BS, Cingi MI, Musmul A "Interaction between grapefruit juice and diazepam in humans." Eur J Drug Metab Pharmacokinet 23 (1998): 55-9
  16. Bailey DG, Malcolm J, Arnold O, Spence JD "Grapefruit juice-drug interactions." Br J Clin Pharmacol 46 (1998): 101-10
  17. Bailey DG, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit juice felodipine interaction: Effect of naringin and 6',7'-dihydroxybergamottin in humans." Clin Pharmacol Ther 64 (1998): 248-56
  18. Garg SK, Kumar N, Bhargava VK, Prabhakar SK "Effect of grapefruit juice on carbamazepine bioavailability in patients with epilepsy." Clin Pharmacol Ther 64 (1998): 286-8
  19. Lilja JJ, Kivisto KT, Neuvonen PJ "Grapefruit juice-simvastatin interaction: Effect on serum concentrations of simvastatin, simvastatin acid, and HMG-CoA reductase inhibitors." Clin Pharmacol Ther 64 (1998): 477-83
  20. Fuhr U, Maier-Bruggemann A, Blume H, et al. "Grapefruit juice increases oral nimodipine bioavailability." Int J Clin Pharmacol Ther 36 (1998): 126-32
  21. Lilja JJ, Kivisto KT, Neuvonen PJ "Grapefruit juice increases serum concentrations of atorvastatin and has no effect on pravastatin." Clin Pharmacol Ther 66 (1999): 118-27
  22. Eagling VA, Profit L, Back DJ "Inhibition of the CYP3A4-mediated metabolism and P-glycoprotein-mediated transport of the HIV-I protease inhibitor saquinavir by grapefruit juice components." Br J Clin Pharmacol 48 (1999): 543-52
  23. Damkier P, Hansen LL, Brosen K "Effect of diclofenac, disulfiram, itraconazole, grapefruit juice and erythromycin on the pharmacokinetics of quinidine." Br J Clin Pharmacol 48 (1999): 829-38
  24. Lee AJ, Chan WK, Harralson AF, Buffum J, Bui BCC "The effects of grapefruit juice on sertraline metabolism: An in vitro and in vivo study." Clin Ther 21 (1999): 1890-9
  25. Dresser GK, Spence JD, Bailey DG "Pharmacokinetic-pharmacodynamic consequences and clinical relevance of cytochrome P450 3A4 inhibition." Clin Pharmacokinet 38 (2000): 41-57
  26. Gunston GD, Mehta U "Potentially serious drug interactions with grapefruit juice." S Afr Med J 90 (2000): 41
  27. Takanaga H, Ohnishi A, Maatsuo H, et al. "Pharmacokinetic analysis of felodipine-grapefruit juice interaction based on an irreversible enzyme inhibition model." Br J Clin Pharmacol 49 (2000): 49-58
  28. Libersa CC, Brique SA, Motte KB, et al. "Dramatic inhibition of amiodarone metabolism induced by grapefruit juice." Br J Clin Pharmacol 49 (2000): 373-8
  29. 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
  30. Zaidenstein R, Soback S, Gips M, Avni B, Dishi V, Weissgarten Y, Golik A, Scapa E "Effect of grapefruit juice on the pharmacokinetics of losartan and its active metabolite E3174 in healthy volunteers." Ther Drug Monit 23 (2001): 369-73
  31. Sato J, Nakata H, Owada E, Kikuta T, Umetsu M, Ito K "Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects." Eur J Clin Pharmacol 44 (1993): 295-8
  32. Flanagan D "Understanding the grapefruit-drug interaction." Gen Dent 53 (2005): 282-5; quiz 286
View all 32 references

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Minor

ethinyl estradiol food

Applies to: Junel 1 / 20 (ethinyl estradiol / norethindrone)

Coadministration with grapefruit juice may increase the bioavailability of oral estrogens. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. In a small, randomized, crossover study, the administration of ethinyl estradiol with grapefruit juice (compared to herbal tea) increased peak plasma drug concentration (Cmax) by 37% and area under the concentration-time curve (AUC) by 28%. Based on these findings, grapefruit juice is unlikely to affect the overall safety profile of ethinyl estradiol. However, as with other drug interactions involving grapefruit juice, the pharmacokinetic alterations are subject to a high degree of interpatient variability. Also, the effect on other estrogens has not been studied.

References

  1. Weber A, Jager R, Borner A, et al. "Can grapefruit juice influence ethinyl estradiol bioavailability?" Contraception 53 (1996): 41-7
  2. Schubert W, Eriksson U, Edgar B, Cullberg G, Hedner T "Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17B-estradiol." Eur J Drug Metab Pharmacokinet 20 (1995): 219-24

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Minor

ethinyl estradiol food

Applies to: Junel 1 / 20 (ethinyl estradiol / norethindrone)

The central nervous system effects and blood levels of ethanol may be increased in patients taking oral contraceptives, although data are lacking and reports are contradictory. The mechanism may be due to enzyme inhibition. Consider counseling women about this interaction which is unpredictable.

References

  1. Hobbes J, Boutagy J, Shenfield GM "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther 38 (1985): 371-80

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Minor

norethindrone food

Applies to: Junel 1 / 20 (ethinyl estradiol / norethindrone)

The central nervous system effects and blood levels of ethanol may be increased in patients taking oral contraceptives, although data are lacking and reports are contradictory. The mechanism may be due to enzyme inhibition. Consider counseling women about this interaction which is unpredictable.

References

  1. Hobbes J, Boutagy J, Shenfield GM "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther 38 (1985): 371-80

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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.

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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.

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