Also indexed as: Alesse-28, Brevicon, Demulen, Desogen,
Desogestrel, Ethynodiol, Genora, Jenest, Levlen, Levonorgestrel, Lo/Ovral, Loestrin,
Mestranol, Micronor, Modicon, Necon, Necon 1/35, Nelova, Nordette, Norethin, Norethindrone,
Norgestrol, Norinyl, Ortho Tri-Cyclen, Ortho-Cept, Ortho-Cyclen, Ortho-Novum, Ovcon, Ovral,
Ovrette, Tri-Norinyl, Triphasil
Oral contraceptives, or birth control pills, are primarily used to prevent pregnancy and to treat menstrual irregularities and endometriosis. Oral contraceptives are available
as an estrogen and progestin combination or as a progestin-only product. The estrogens used in
oral contraceptives are different from those used in hormone-replacement therapy.
Consequently, interactions involving estrogens used in birth control pills may or may not be
similar to those used in hormone replacement.
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
| May Be Beneficial: Depletion or
interference—The medication may deplete or interfere with the absorption or
function of the nutrient. Taking these nutrients may help replenish them.
| May Be Beneficial: Side effect
reduction/prevention—Taking these supplements may help reduce the likelihood and/or
severity of a potential side effect caused by the medication.
| May Be Beneficial: Supportive
interaction—Taking these supplements may support or otherwise help your medication
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results.
St. John’s wort*
Check: Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details.
|Interactions common to many, if not all, Oral
Contraceptives are described in this article. Interactions reported for only one or several
drugs in this class may not be listed in this article. Some drugs listed in this article are
linked to articles specific to that respective drug; please refer to those individual drug
articles. The information in this article may not necessarily apply to drugs in this class for
which no separate article exists. If you are taking an Oral Contraceptive for which no
separate article exists, talk with your doctor or pharmacist.
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
Interactions that are common to oral contraceptives are described below. For interactions
involving drugs used in hormone-replacement therapy, refer to the article on estrogen.
Mestranol and Norethindrone
- Genora 1/50®
- Nelova 1/50®
- Norethin 1/50®
- Ortho-Novum 1/50®
Ethinyl estradiol and Norethindrone
- Genora 1/35®
- GenCept 1/35®
- Loestrin 1.5/30®
- Necon 1/25®
- Necon 10/11®
- Necon 0.5/30®
- Necon 1/50®
- Nelova 1/35®
- Nelova 10/11 ®
- Norinyl 1/35®
- Norlestin 1/50®
- Ortho Novum 1/35®
- Ortho Novum 10/11®
- Ortho Novum 7/7/7®
Ethinyl estradiol and Ethynodiol
- Demulen 1/35®
- Demulen 1/50®
- Nelulen 1/25®
- Nelulen 1/50®
Ethinyl estradiol and Norgestrel
Ethinyl estradiol and Levonorgestrel
- Levora 0.15/30®
- Preven® Emergency Contraceptive Kit
Ethinyl estradiol and Desogestrel
- Plan B®
Interactions with Dietary Supplements
Oral contraceptive (OC) use can cause folic acid depletion.1 In a double-blind
trial of OC users with cervical dysplasia,
supplementation with very large amounts (10 mg per day) of folic acid improved cervical
health.2 Women with cervical dysplasia diagnosed while they are taking OCs should
consult a doctor. Mega-folate supplementation should not be attempted without a doctor’s
supervision, nor is there any reason to believe that folic acid supplementation would help
people with cervical cancer.
Menstrual blood loss is typically reduced with use of OCs. This can lead to increased iron
stores and, presumably, a decreased need for iron in premenopausal women.3
Premenopausal women taking OCs should have their iron levels monitored and talk with their
prescribing doctor before using iron-containing supplements.
Women using OCs were found to have significantly lower serum magnesium levels in a controlled
study.4 In a preliminary study, blood levels of magnesium decreased in women taking
an OC containing ethinyl estradiol and levonorgestrel.5 Although the importance of
this interaction remains somewhat unclear, supplementation with 250–350 mg of magnesium
per day is a safe and reasonable supplemental level for most adults.
Oral contraceptives have been associated with vitamin B6 depletion and clinical depression. In a small, double-blind study of women
with depression taking OCs, vitamin B6 (20 mg twice per day) improved depression.6
Half of the women in the study showed laboratory evidence of vitamin B6 deficiency.
A review of literature suggests that women who use OCs may experience decreased vitamin B1, B2,
B3, B12, C, and
zinc levels.7 8 9 OC use has been associated with
increased absorption of calcium and copper and with increased blood levels of copper and
vitamin A.10 11
12 OCs may interfere with manganese
absorption.13 The clinical importance of these actions remains unclear.
Interactions with Herbs
Eight cases reported to the Medical Products Agency of Sweden suggest that St. John’s
wort may interact with oral contraceptives and cause intramenstrual bleeding and/or changes in
menstrual bleeding.14 One reviewer has suggested that St. John’s wort may
reduce serum levels of estradiol.15 It should be noted, however, that only three of
the eight Swedish women returned to normal menstrual cycles after stopping St. John’s
wort. Women taking oral contraceptives for birth control should consult with their doctor
before taking St. John’s wort.
Interactions with Foods and Other Compounds
Tobacco (Nicotiana species)
Women who smoke and use OCs have a five-times greater risk of dying from a heart attack than OC users who do not
smoke.16 Women over the age of 35 who smoke and use OCs have a greatly increased
risk of death related to circulatory
disease.17 Avoiding or quitting smoking is good for health.
1. Lindenbaum J, Whitehead N, Reyner F. Oral contraceptive hormones,
folate metabolism, and the cervical epithelium. Am J Clin Nutr
2. Butterworth CE Jr, Hatch KD, Gore H, et al. Improvement in cervical
dysplasia associated with folic acid therapy in users of oral contraceptives. Am J Clin
Nutr 1982 ;35:73–82.
3. Frassinelli-Gunderson EP, Margen S, Brown JR. Iron stores in users of
oral contraceptive agents. Am J Clin Nutr 1985;41(4):703.
4. Olatunbosum DA, Adeniyi FA, Adadevoh BK. Effect of oral contraceptives
on serum magnesium levels. Int J Fertil 1974;19:224–6.
5. Blum M, Kitai E, Ariel Y, et al. Oral contraceptive lowers serum
magnesium. Harefuah 1991;121:363–4 [in Hebrew].
6. Adams PW, Wynn V, Rose DP, et al. Effect of pyridoxine hydrochloride
(vitamin B6) upon depression associated with oral contraception. Lancet
7. Werbach MR. Foundations of Nutritional Medicine. Tarzana, CA:
Third Line Press, 1997, 210–1 [review].
8. Wynn V. Vitamins and oral contraceptive use. Lancet
9. Holt GA. Food & Drug Interaction. Chicago: Precept Press,
10. Werbach MR. Foundations of Nutritional Medicine. Tarzana,
CA: Third Line Press, 1997, 210–1 [review].
11. Wynn V. Vitamins and oral contraceptive use. Lancet
12. Berg G, Kohlmeier L, Brenner H. Effect of oral contraceptive
progestins on serum copper concentration. Eur J Clin Nutr 1998;52:711–5.
13. Holt GA. Food & Drug Interaction. Chicago: Precept
Press, 1998, 197.
14. Safety of St. John’s wort (Hypericum perforatum)
[letters to the editor from various authors]. Lancet 2000;355:575–7.
15. Ernst E. Second thoughts about safety of St. John’s wort
[letter]. Lancet 1999;354:2014–6.
16. Threlkeld DS, ed. Hormones, Oral Contraceptives. In Facts and
Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1994,
17. Threlkeld DS, ed. Hormones, Oral Contraceptives. In Facts and
Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Jul 1994,