Grapefruit and Birth control?

emergencytennis

This. It's difficult to estimate the clinical outcomes because there are large inter-individual differences in drugs metabolism and not many clinical trials have been made (check this: http://www.ncbi.nlm.nih.gov/pubmed/12749182.
Just to be sure, doctors tend to discourage patients from eating grapefruit on a regular basis. (I'm not a doc, I'm a med student)

That study tested the response of eight women, with no control group. Pretty sad, really.

I hate it when these studies have a small group or no control. Why did they even bother doing the study if we're looking at data that is not representative of the population nor even statistically sig? Didn't they take the same science classes I did warning us that this simply doesn't fly?

Pretty sad indeed, that's why I haven't said "STOP EATING GRAPEFRUIT OR YOU'LL DIE TOMORROW"
There's not enough clinical data, so doctors prefer to "play it safe" and discourage patients from eating grapefruit.

Could you quote the doctors recommending women limit their intake of grapefruit in case it reduces the efficacy of their oral contraceptive? That is what the author was looking for, I think.

tinylightsbelow

Maybe you could get a copper IUD? It makes sense since you NEVER want kids and they last 10 years... and the copper one is nonhormonal so it probably won't interact with grapefruit juice.

tinylightsbelow

Maybe you could get a copper IUD? It makes sense since you NEVER want kids and they last 10 years... and the copper one is nonhormonal so it probably won't interact with grapefruit juice.

sbarella

Could you quote the doctors recommending women limit their intake of grapefruit in case it reduces the efficacy of their oral contraceptive? That is what the author was looking for, I think.

Yes, not because it reduces efficacy (as already stated) but because it increases estrogen levels. It's written on my texbooks and I experienced it during my training. Doctors know it's probably an excess of caution (at least in this case, NOT when dealing with other drugs like carbamazepine) but it's common practice to do so.

emergencytennis

Could you quote the doctors recommending women limit their intake of grapefruit in case it reduces the efficacy of their oral contraceptive? That is what the author was looking for, I think.

Yes, not because it reduces efficacy (as already stated) but because it increases estrogen levels. It's written on my texbooks and I experienced it during my training. Doctors know it's probably an excess of caution (at least in this case, NOT when dealing with other drugs like carbamazepine) but it's common practice to do so.

Anecdotes don't carry much weight with me when it comes to medical matters

macybean

Grapefruit usually increases absorption of medications that it effects, and your medication should be labeled with a warning if grapefruit is an issue.
I would consult my pharmacist (way better than your doctor for medication-related questions).
My one-person, non-controlled study shows a 100% effectiveness of oral contraceptives despite eating grapefruit:)

SoDamnHungry

Maybe you could get a copper IUD? It makes sense since you NEVER want kids and they last 10 years... and the copper one is nonhormonal so it probably won't interact with grapefruit juice.

Or consider getting something permanent done? Only because you said you NEVER want kids, so that way you wouldn't have to worry regardless of what you eat.

ClementineGeorg

I have heard some things about a substance in grapefruit that interacts with medicines (not only birth control).

But again, birth control is not really a 100% accurate method for not having children. It's like... 98-99% sure. And again, you take hormones... they work because they un-balance the hormones in your body. If you eat something that affects hormone production, if you have some health issues at some point... the birth control will not act the same. Hormone production in your body is, like weight loss, not linear.

MMarsh6115

To address some of the comments:
1) Vitamin C has nothing to do with this issue as someone above stated. It is furanocoumarins that are causing the inhibition of CYP3A4. It is found in grapefruit and sour (Seville) oranges. It is NOT an issue related to all citrus fruits.
2) The components of BC pills are not the only compounds affected by this interaction. Anything that is CYP3A4 substrate can potentially be affected. As someone else mentioned, the interaction with statins (cholesterol lowering drugs) and carbamazepine can be serious due to the increase in exposure. Further, some research indicates that grapefruit may affect other pathways and transporters as well and thus impact other substrates.
3) The design of the study quoted above is standard for drug-interaction studies, i.e, they are not typically placebo-controlled and the number of subjects are usually small. Each subject acts as their own control and are dosed with, for example, the substrate alone (the reference treatment) and in combination with the other drug or substance (the test treatment), thereby allowing for evaluation of the potential change in the pharmacokinetics of the reference drug with and without the potential interacting drug. This is scientifically sound. In addition, the duration of dosing is often short, but is long enough to elicit a potential interaction. Dosing is also appropriate in these studies. This design also helps to address differences in the extent of metabolism in different people (as Sbarella mentioned).
4) The drug that's typically used to test the effect of CYP3A4 inhibition on another drug is ketoconazole (an antifungal), which is a strong CYP3A4 inhibitor. Grapefruit may not be as potent an inhibitor as keto, but you will likely find more info on keto interactions on the web.
5) Someone also mentioned St John's wort, which is an inducer of the CYP3A4 enzyme, which results in a decrease in exposure to the components of BC pills. Some antibiotics do this also, thus the classic recommendation to use an alternate method of BC if you use an antibiotic while on BC pills.
6) Lastly, the interaction with grapefruit is not influenced much by when you ingest it in relation to when you take your BC pills as the effect can last for 24 hours or longer.