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Drug Interactions between ethinyl estradiol and Grisactin 500

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

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Interactions between your drugs

Major

griseofulvin ethinyl estradiol

Applies to: Grisactin 500 (griseofulvin) and ethinyl estradiol

ADDITIONAL CONTRACEPTION RECOMMENDED: Limited clinical data suggest that griseofulvin may reduce the efficacy of contraceptive hormones. There have been case reports of menstrual abnormalities (e.g., breakthrough bleeding, amenorrhea, irregular menses) or unintended pregnancy following the addition of griseofulvin in patients receiving long-term oral contraceptives. The proposed mechanism is accelerated clearance of the hormones due to induction of hepatic CYP450 enzymes by griseofulvin. However, data evaluating the clinical significance of the enzyme-inducing effects of griseofulvin in humans are lacking.

MANAGEMENT: Women using low-dose hormonal contraceptives should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant therapy with griseofulvin. Because griseofulvin has been shown to be teratogenic in animal studies and is capable of inducing aneuploidy (abnormal segregation of chromosomes following cell division) in mammalian cells in vitro and in vivo, it is particularly important that patients not become pregnant during treatment. Therefore, additional methods of birth control should be used during and for one month after griseofulvin therapy. Input from a gynecologist or similar expert on adequate contraception, including emergency contraception, should be sought as needed. Intrauterine systems are unlikely to be significantly affected because of their local action.

References (12)
  1. Weber JC (1984) "Interaction between oral contraceptives and griseofulvin." Br Med J, 288, p. 1125-6
  2. McDaniel PA, Caldroney RD (1986) "Oral contraceptives and griseofulvin interaction." Drug Intell Clin Pharm, 20, p. 384
  3. Cote J (1990) "Interaction of griseofulvin and oral contraceptives." J Am Acad Dermatol, 22, p. 124-5
  4. "Product Information. Grifulvin V (griseofulvin)." Ortho McNeil Pharmaceutical
  5. van Dijke CP, Weber JC (1984) "Interaction between oral contraceptives and griseofulvin." Br Med J (Clin Res Ed), 288, p. 1125-6
  6. Bollen M (1995) "Use of antibiotics when taking the oral contraceptive pill." Aust Fam Physician, 24, p. 928-9
  7. Helms SE, Bredle DL, Zajic J, Jarjoura D, Brodell RT, Krishnarao I (1997) "Oral contraceptive failure rates and oral antibiotics." J Am Acad Dermatol, 36, p. 705-10
  8. Weisberg E (1999) "Interactions between oral contraceptives and antifungals antibacterials - Is contraceptive failure the result?." Clin Pharmacokinet, 36, p. 309-13
  9. Weaver K, Glasier A (1999) "Interaction between broad-spectrum antibiotics and the combined oral contraceptive pill: a literature review." Contraception, 59, p. 71-8
  10. 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
  11. Back DJ, Grimmer SF, Orme ML, Proudlove D, Mann RD, Breckenridge AM (1988) "Evaluation of Committee on Safety of Medicines yellow card reports on oral contraceptive-drug interactions with anticonvulsants and antibiotics." Br J Clin Pharmacol, 25, p. 527-32
  12. Faculty of Sexual & Reproductive Healthcare (2016) "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf"

Drug and food interactions

Moderate

griseofulvin food

Applies to: Grisactin 500 (griseofulvin)

MONITOR: Isolated case reports have suggested that the ingestion of alcohol during griseofulvin therapy may rarely cause disulfiram-like reactions, flushing, tachycardia, or increased effects of alcohol. The mechanism is unknown.

MANAGEMENT: Patients should be advised of the possibility of increased adverse effects or a disulfiram-like reaction.

References (3)
  1. "Product Information. Grifulvin V (griseofulvin)." Ortho McNeil Pharmaceutical
  2. (2002) "Product Information. Fulvicin P/G (griseofulvin)." Schering Corporation
  3. Cerner Multum, Inc. "Australian Product Information."
Moderate

ethinyl estradiol food

Applies to: ethinyl estradiol

MONITOR: Coadministration of ethinyl estradiol may increase the plasma concentrations of drugs that are primarily metabolized by CYP450 1A2. In a study of 30 healthy volunteers administered the CYP450 1A2 substrate tizanidine, the systemic exposure (AUC) of tizanidine was 3.9 times greater in women using an oral contraceptive containing ethinyl estradiol.

MANAGEMENT: Patients should be monitored for increased adverse effects of the CYP450 1A2 substrate during concomitant use with ethinyl estradiol. Product labeling for the specific CYP450 1A2 substrate should be consulted for additional recommendations.

References (1)
  1. Granfors MT, Backman JT, Laitila J, Neuvonen PJ (2005) "Oral contraceptives containing ethinyl estradiol and gestodene markedly increase plasma concentrations and effects of tizanidine by inhibiting cytochrome P450 1A2." Clin Pharmacol Ther, 78, p. 400-11
Minor

ethinyl estradiol food

Applies to: ethinyl estradiol

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 (2)
  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
Minor

ethinyl estradiol food

Applies to: ethinyl estradiol

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

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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