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Drug Interactions between Delyla and rifapentine

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

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Major

ethinyl estradiol rifapentine

Applies to: Delyla (ethinyl estradiol / levonorgestrel) and rifapentine

MONITOR CLOSELY: Coadministration with rifampin or other rifamycins may reduce the efficacy of estrogen and progestin hormones that are CYP450 3A4 substrates. The interaction stems from accelerated clearance of the hormone(s) as well as decreased plasma concentrations of unbound (active) hormone(s) due to induction of CYP450 enzymatic activity and hormone-binding globulin capacity by rifampin and to a lesser extent with other rifamycins. In a study of 28 healthy premenopausal women on a combination oral contraceptive pill, coadministration with rifampin (300 mg/day for 10 days) reduced ethinyl estradiol peak plasma concentration (Cmax) and systemic exposure (AUC) by 42% and 64%, respectively, while the same dosage of rifabutin reduced ethinyl estradiol Cmax and AUC by 20% and 35%, respectively. Norethindrone AUC was reduced by 60% with rifampin and 20% with rifabutin. In addition, FSH and LH levels increased following rifamycin therapy, and the incidence of spotting was significantly higher after coadministration with rifampin (36.4%) and rifabutin (21.7%) than during the control cycle (3.7%). This interaction is not thought to be clinically relevant for persons using the progestin-only (DMPA) injection (as serum progestin levels are expected to remain adequate), locally acting levonorgestrel-releasing intrauterine systems (as the local effect on the endometrium is unaffected by enzyme induction), and the non-hormonal copper intrauterine device for contraception. Similarly, this interaction may not be as significant for each hormone. A pharmacokinetic study (n=65) in postmenopausal women examined the effects of rifampin (600 mg/day) on the exposure of levonorgestrel (0.03 mg, n=13), norethindrone (0.35 mg, n=14), desogestrel (0.075 mg, n=12), dienogest (2 mg, n=12), and a combination of drospirenone and ethinyl estradiol (3 mg/0.03 mg, n=14). Bound and unbound hormone levels were reviewed. The largest decreases in AUC were observed for etonogestrel (desogestrel's active metabolite), dienogest, and drospirenone at >80%. Levonorgestrel, norethindrone, and ethinyl estradiol had reductions in AUC between 50% and less than 80%.

MANAGEMENT: Caution and close clinical monitoring for reduced efficacy are advised for people using an estrogen and/or progestin-containing product for purposes other than contraception. These patients should be counseled to report any changes in efficacy of the hormonal product to their healthcare provider. Women using estrogens and/or progestins for contraception should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant rifamycin therapy, even when given in short doses. Long-acting progestin-only injections and levonorgestrel-releasing intrauterine systems may be considered as alternative contraceptive agents. For the most current guidance, local relevant guidelines should be consulted. In general, alternative or additional methods of non-hormonal birth control should be used during and for at least 28 days after rifamycin therapy.

The following apply only to the specific medications (combined oral contraception) or situations (emergency contraception) specified:

-If a combination oral contraceptive pill is chosen despite the risks, a regimen containing at least 30 mcg of ethinyl estradiol per day or equivalent should be selected. Some authorities have suggested increasing to 50 mcg of ethinyl estradiol or equivalent; however, they recommend advising the patient that contraceptive effectiveness, even at this dose, may be reduced and that there could be an increased risk of thrombosis if exposure to ethinyl estradiol is increased.

-For emergency contraception in patients who have used a hepatic enzyme inducer in the past 4 weeks, a non-hormonal emergency contraceptive (e.g., copper intrauterine device) is considered preferable. If this is not possible, some authorities recommend that the usual dose of levonorgestrel (1.5 mg) be doubled to 3 mg and taken as a single dose as soon as possible (typically within 72 hours, though some guidelines suggest up to 96 hours, of unprotected sexual intercourse). However, the efficacy of this regimen is unknown.

References

  1. Venkatesan K (1992) "Pharmacokinetic drug interactions with rifampicin." Clin Pharmacokinet, 22, p. 47-65
  2. Borcherding SM, Baciewicz AM, Self TH (1992) "Update on rifampin drug interactions." Arch Intern Med, 152, p. 711-6
  3. Baciewicz AM (1985) "Oral contraceptive drug interactions." Ther Drug Monit, 7, p. 26-35
  4. Joshi JV, Joshi UM, Sankolli GM, et al. (1980) "A study of interaction of a low-dose combination oral contraceptive with anti-tubercular drugs." Contraception, 21, p. 617-29
  5. Bint AJ, Burtt I (1980) "Adverse antibiotic drug interactions." Drugs, 20, p. 57-68
  6. Skolnick JL, Stoler BS, Katz DB, Anderson WH (1976) "Rifampin, oral contraceptives, and pregnancy." JAMA, 236, p. 1382
  7. Dossetor J (1975) "Drug interactions with oral contraceptives." Br Med J, 4, p. 467-8
  8. (2001) "Product Information. Mycobutin (rifabutin)." Pharmacia and Upjohn
  9. (2001) "Product Information. Rifadin (rifampin)." Hoechst Marion Roussel
  10. Baciewicz AM, Self TH (1984) "Rifampin drug interactions." Arch Intern Med, 144, p. 1667-71
  11. Nocke-finck L (1973) "Effects of rifampicin on menstral cycle and on estrogen excretion in patients taking oral contraceptives." JAMA, 226, p. 378
  12. Bolt HM, Bolt M, Kappus H (1977) "Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man." Acta Endocrinol (Copenh), 85, p. 189-97
  13. Back DJ, Breckenridge AM, Crawford FE, et al. (1980) "The effect of rifampicin on the pharmacokinetics of ethynylestradiol in women." Contraception, 21, p. 135-43
  14. Back DJ, Breckenridge AM, Crawford F, et al. (1979) "The effect of rifampicin on norethisterone pharmacokinetics." Eur J Clin Pharmacol, 15, p. 193-7
  15. Szoka PR, Edgren RA (1988) "Drug interactions with oral contraceptives: compilation and analysis of an adverse experience report database." Fertil Steril, 49, s31-8
  16. Back DJ, Orme ML (1990) "Pharmacokinetic drug interactions with oral contraceptives." Clin Pharmacokinet, 18, p. 472-84
  17. D'Arcy PF (1986) "Drug interactions with oral contraceptives." Drug Intell Clin Pharm, 20, p. 353-62
  18. Strayhorn VA, Baciewicz AM, Self TH (1997) "Update on rifampin drug interactions, III." Arch Intern Med, 157, p. 2453-8
  19. Michalets EL (1998) "Update: clinically significant cytochrome P-450 drug interactions." Pharmacotherapy, 18, p. 84-112
  20. (2001) "Product Information. Priftin (rifapentine)." Hoechst Marion Roussel
  21. Back DJ, Breckenridge AM, Crawford FE, MacIver M, Orne ML, Rowe PH (1981) "Interindividual variation and drug interactions with hormonal steroid contraceptives." Drugs, 21, p. 46-61
  22. LeBel M, Masson E, Guilbert E, Colborn D, Paquet F, Allard S, Vallee F, Narang PK (1998) "Effects of rifabutin and rifampicin on the pharmacokinetics of ethinylestradiol and norethindrone." J Clin Pharmacol, 38, p. 1042-50
  23. Barditch-Crovo P, Trapnell CB, Ette E, et al. (1999) "The effects of rifampin and rifabutin on the pharmacokinetics and pharmacodynamics of a combination oral contraceptive." Clin Pharmacol Ther, 65, p. 428-38
  24. Weisberg E (1999) "Interactions between oral contraceptives and antifungals antibacterials - Is contraceptive failure the result?." Clin Pharmacokinet, 36, p. 309-13
  25. Weaver K, Glasier A (1999) "Interaction between broad-spectrum antibiotics and the combined oral contraceptive pill: a literature review." Contraception, 59, p. 71-8
  26. Zachariassen RD (1994) "Loss of oral contraceptive efficacy by concurrent antibiotic administration." Women Health, 22, p. 17-26
  27. Dickinson BD, Altman RD, Nielsen NH, Sterling ML (2001) "Drug interactions between oral contraceptives and antibiotics." Obstet Gynecol, 98(5 Pt 1), p. 853-60
  28. Archer JS, Archer DF (2002) "Oral contraceptive efficacy and antibiotic interaction: A myth debunked." J Am Acad Dermatol, 46, p. 917-23
  29. DeRossi SS, Hersh EV (2002) "Antibiotics and oral contraceptives." Dent Clin North Am, 46, p. 653-64
  30. (2005) "FFPRHC Guidance (April 2005). Drug interactions with hormonal contraception." J Fam Plann Reprod Health Care, 31, p. 139-51
  31. Bounds W, Guillebaud J (2002) "Observational series on women using the contraceptive Mirena concurrently with anti-epileptic and other enzyme-inducing drugs." J Fam Plann Reprod Health Care, 28, p. 78-80
  32. Faculty of Sexual & Reproductive Healthcare (2016) "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf"
  33. Curtis KM, Tepper NK, Jatlaoui TC, et al. (2023) U.S. medical eligibility criteria (US MEC) for contraceptive use. https://www.cdc.gov/reproductivehealth/contraception/mmwr/mec/index.html
  34. Faculty of Sexual & Reproductive Healthcare (2023) FSRH CEU guidance: drug interactions with hormonal contraception (may 2022) https://www.fsrh.org/standards-and-guidance/documents/ceu-clinical-guidance-drug-interactions-with-hormonal/
  35. Allen K (2012) "Contraception - common issues and practical suggestions." Aust Fam Physician, 41, p. 770-2
  36. (2021) "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India), 2
  37. (2021) "Product Information. Priftin (rifapentine)." sanofi-aventis
  38. Macleods Pharmaceuticals Limited (2024) Rifapentine 300 mg tablets (Macleods Pharmaceuticals Ltd), TB398. WHO-PQ recommended summary of product characteristics. https://extranet.who.int/prequal/sites/default/files/whopar_files/TB398part4v1.pdf
  39. Wiesinger H, Klein S, Rottmann A, et al. (2020) "The effects of weak and strong CYP3A induction by rifampicin on the pharmacokinetics of five progestins and ethinylestradiol compared to midazolam." Clin Pharmacol Ther, 108, p. 798-807
View all 39 references

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Major

levonorgestrel rifapentine

Applies to: Delyla (ethinyl estradiol / levonorgestrel) and rifapentine

MONITOR CLOSELY: Coadministration with rifampin or other rifamycins may reduce the efficacy of estrogen and progestin hormones that are CYP450 3A4 substrates. The interaction stems from accelerated clearance of the hormone(s) as well as decreased plasma concentrations of unbound (active) hormone(s) due to induction of CYP450 enzymatic activity and hormone-binding globulin capacity by rifampin and to a lesser extent with other rifamycins. In a study of 28 healthy premenopausal women on a combination oral contraceptive pill, coadministration with rifampin (300 mg/day for 10 days) reduced ethinyl estradiol peak plasma concentration (Cmax) and systemic exposure (AUC) by 42% and 64%, respectively, while the same dosage of rifabutin reduced ethinyl estradiol Cmax and AUC by 20% and 35%, respectively. Norethindrone AUC was reduced by 60% with rifampin and 20% with rifabutin. In addition, FSH and LH levels increased following rifamycin therapy, and the incidence of spotting was significantly higher after coadministration with rifampin (36.4%) and rifabutin (21.7%) than during the control cycle (3.7%). This interaction is not thought to be clinically relevant for persons using the progestin-only (DMPA) injection (as serum progestin levels are expected to remain adequate), locally acting levonorgestrel-releasing intrauterine systems (as the local effect on the endometrium is unaffected by enzyme induction), and the non-hormonal copper intrauterine device for contraception. Similarly, this interaction may not be as significant for each hormone. A pharmacokinetic study (n=65) in postmenopausal women examined the effects of rifampin (600 mg/day) on the exposure of levonorgestrel (0.03 mg, n=13), norethindrone (0.35 mg, n=14), desogestrel (0.075 mg, n=12), dienogest (2 mg, n=12), and a combination of drospirenone and ethinyl estradiol (3 mg/0.03 mg, n=14). Bound and unbound hormone levels were reviewed. The largest decreases in AUC were observed for etonogestrel (desogestrel's active metabolite), dienogest, and drospirenone at >80%. Levonorgestrel, norethindrone, and ethinyl estradiol had reductions in AUC between 50% and less than 80%.

MANAGEMENT: Caution and close clinical monitoring for reduced efficacy are advised for people using an estrogen and/or progestin-containing product for purposes other than contraception. These patients should be counseled to report any changes in efficacy of the hormonal product to their healthcare provider. Women using estrogens and/or progestins for contraception should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant rifamycin therapy, even when given in short doses. Long-acting progestin-only injections and levonorgestrel-releasing intrauterine systems may be considered as alternative contraceptive agents. For the most current guidance, local relevant guidelines should be consulted. In general, alternative or additional methods of non-hormonal birth control should be used during and for at least 28 days after rifamycin therapy.

The following apply only to the specific medications (combined oral contraception) or situations (emergency contraception) specified:

-If a combination oral contraceptive pill is chosen despite the risks, a regimen containing at least 30 mcg of ethinyl estradiol per day or equivalent should be selected. Some authorities have suggested increasing to 50 mcg of ethinyl estradiol or equivalent; however, they recommend advising the patient that contraceptive effectiveness, even at this dose, may be reduced and that there could be an increased risk of thrombosis if exposure to ethinyl estradiol is increased.

-For emergency contraception in patients who have used a hepatic enzyme inducer in the past 4 weeks, a non-hormonal emergency contraceptive (e.g., copper intrauterine device) is considered preferable. If this is not possible, some authorities recommend that the usual dose of levonorgestrel (1.5 mg) be doubled to 3 mg and taken as a single dose as soon as possible (typically within 72 hours, though some guidelines suggest up to 96 hours, of unprotected sexual intercourse). However, the efficacy of this regimen is unknown.

References

  1. Venkatesan K (1992) "Pharmacokinetic drug interactions with rifampicin." Clin Pharmacokinet, 22, p. 47-65
  2. Borcherding SM, Baciewicz AM, Self TH (1992) "Update on rifampin drug interactions." Arch Intern Med, 152, p. 711-6
  3. Baciewicz AM (1985) "Oral contraceptive drug interactions." Ther Drug Monit, 7, p. 26-35
  4. Joshi JV, Joshi UM, Sankolli GM, et al. (1980) "A study of interaction of a low-dose combination oral contraceptive with anti-tubercular drugs." Contraception, 21, p. 617-29
  5. Bint AJ, Burtt I (1980) "Adverse antibiotic drug interactions." Drugs, 20, p. 57-68
  6. Skolnick JL, Stoler BS, Katz DB, Anderson WH (1976) "Rifampin, oral contraceptives, and pregnancy." JAMA, 236, p. 1382
  7. Dossetor J (1975) "Drug interactions with oral contraceptives." Br Med J, 4, p. 467-8
  8. (2001) "Product Information. Mycobutin (rifabutin)." Pharmacia and Upjohn
  9. (2001) "Product Information. Rifadin (rifampin)." Hoechst Marion Roussel
  10. Baciewicz AM, Self TH (1984) "Rifampin drug interactions." Arch Intern Med, 144, p. 1667-71
  11. Nocke-finck L (1973) "Effects of rifampicin on menstral cycle and on estrogen excretion in patients taking oral contraceptives." JAMA, 226, p. 378
  12. Bolt HM, Bolt M, Kappus H (1977) "Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man." Acta Endocrinol (Copenh), 85, p. 189-97
  13. Back DJ, Breckenridge AM, Crawford FE, et al. (1980) "The effect of rifampicin on the pharmacokinetics of ethynylestradiol in women." Contraception, 21, p. 135-43
  14. Back DJ, Breckenridge AM, Crawford F, et al. (1979) "The effect of rifampicin on norethisterone pharmacokinetics." Eur J Clin Pharmacol, 15, p. 193-7
  15. Szoka PR, Edgren RA (1988) "Drug interactions with oral contraceptives: compilation and analysis of an adverse experience report database." Fertil Steril, 49, s31-8
  16. Back DJ, Orme ML (1990) "Pharmacokinetic drug interactions with oral contraceptives." Clin Pharmacokinet, 18, p. 472-84
  17. D'Arcy PF (1986) "Drug interactions with oral contraceptives." Drug Intell Clin Pharm, 20, p. 353-62
  18. Strayhorn VA, Baciewicz AM, Self TH (1997) "Update on rifampin drug interactions, III." Arch Intern Med, 157, p. 2453-8
  19. Michalets EL (1998) "Update: clinically significant cytochrome P-450 drug interactions." Pharmacotherapy, 18, p. 84-112
  20. (2001) "Product Information. Priftin (rifapentine)." Hoechst Marion Roussel
  21. Back DJ, Breckenridge AM, Crawford FE, MacIver M, Orne ML, Rowe PH (1981) "Interindividual variation and drug interactions with hormonal steroid contraceptives." Drugs, 21, p. 46-61
  22. LeBel M, Masson E, Guilbert E, Colborn D, Paquet F, Allard S, Vallee F, Narang PK (1998) "Effects of rifabutin and rifampicin on the pharmacokinetics of ethinylestradiol and norethindrone." J Clin Pharmacol, 38, p. 1042-50
  23. Barditch-Crovo P, Trapnell CB, Ette E, et al. (1999) "The effects of rifampin and rifabutin on the pharmacokinetics and pharmacodynamics of a combination oral contraceptive." Clin Pharmacol Ther, 65, p. 428-38
  24. Weisberg E (1999) "Interactions between oral contraceptives and antifungals antibacterials - Is contraceptive failure the result?." Clin Pharmacokinet, 36, p. 309-13
  25. Weaver K, Glasier A (1999) "Interaction between broad-spectrum antibiotics and the combined oral contraceptive pill: a literature review." Contraception, 59, p. 71-8
  26. Zachariassen RD (1994) "Loss of oral contraceptive efficacy by concurrent antibiotic administration." Women Health, 22, p. 17-26
  27. Dickinson BD, Altman RD, Nielsen NH, Sterling ML (2001) "Drug interactions between oral contraceptives and antibiotics." Obstet Gynecol, 98(5 Pt 1), p. 853-60
  28. Archer JS, Archer DF (2002) "Oral contraceptive efficacy and antibiotic interaction: A myth debunked." J Am Acad Dermatol, 46, p. 917-23
  29. DeRossi SS, Hersh EV (2002) "Antibiotics and oral contraceptives." Dent Clin North Am, 46, p. 653-64
  30. (2005) "FFPRHC Guidance (April 2005). Drug interactions with hormonal contraception." J Fam Plann Reprod Health Care, 31, p. 139-51
  31. Bounds W, Guillebaud J (2002) "Observational series on women using the contraceptive Mirena concurrently with anti-epileptic and other enzyme-inducing drugs." J Fam Plann Reprod Health Care, 28, p. 78-80
  32. Faculty of Sexual & Reproductive Healthcare (2016) "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf"
  33. Curtis KM, Tepper NK, Jatlaoui TC, et al. (2023) U.S. medical eligibility criteria (US MEC) for contraceptive use. https://www.cdc.gov/reproductivehealth/contraception/mmwr/mec/index.html
  34. Faculty of Sexual & Reproductive Healthcare (2023) FSRH CEU guidance: drug interactions with hormonal contraception (may 2022) https://www.fsrh.org/standards-and-guidance/documents/ceu-clinical-guidance-drug-interactions-with-hormonal/
  35. Allen K (2012) "Contraception - common issues and practical suggestions." Aust Fam Physician, 41, p. 770-2
  36. (2021) "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India), 2
  37. (2021) "Product Information. Priftin (rifapentine)." sanofi-aventis
  38. Macleods Pharmaceuticals Limited (2024) Rifapentine 300 mg tablets (Macleods Pharmaceuticals Ltd), TB398. WHO-PQ recommended summary of product characteristics. https://extranet.who.int/prequal/sites/default/files/whopar_files/TB398part4v1.pdf
  39. Wiesinger H, Klein S, Rottmann A, et al. (2020) "The effects of weak and strong CYP3A induction by rifampicin on the pharmacokinetics of five progestins and ethinylestradiol compared to midazolam." Clin Pharmacol Ther, 108, p. 798-807
View all 39 references

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Drug and food interactions

Moderate

levonorgestrel food

Applies to: Delyla (ethinyl estradiol / levonorgestrel)

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

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Moderate

rifapentine food

Applies to: rifapentine

ADJUST DOSING INTERVAL: Administration with food may increase the oral bioavailability of rifapentine and reduce the incidence of gastrointestinal adverse events. Administration with a high fat meal typically increases rifapentine's maximum concentration (Cmax) and systemic exposure (AUC) by approximately 40% to 50% over that observed when rifapentine is administered under fasting conditions. Rifapentine is often prescribed in combination with isoniazid. When single doses of rifapentine (900 mg) and isoniazid (900 mg) were administered with a low fat, high carbohydrate breakfast, the Cmax and AUC of rifapentine increased by 47% and 51%, respectively. On the other hand, isoniazid's Cmax and AUC decreased by 46% and 23%, respectively.

MANAGEMENT: Products containing oral rifapentine as the sole ingredient recommend administration with a meal to increase bioavailability and reduce the occurrence of gastrointestinal upset, nausea, and/or vomiting. Consultation of product labeling for combination products and/or relevant guidelines may be helpful if rifapentine is combined with a medication that is typically taken on an empty stomach.

References

  1. (2021) "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India), 2
  2. (2021) "Product Information. Priftin (rifapentine)." sanofi-aventis

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Minor

ethinyl estradiol food

Applies to: Delyla (ethinyl estradiol / levonorgestrel)

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

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Minor

ethinyl estradiol food

Applies to: Delyla (ethinyl estradiol / levonorgestrel)

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 (1985) "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther, 38, p. 371-80

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Minor

levonorgestrel food

Applies to: Delyla (ethinyl estradiol / levonorgestrel)

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 (1985) "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther, 38, p. 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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.