antibiotics & the pill

[alli]

On birth control pills they always have the warning "certain antibiotics may decrease the effectiveness of this medication". But by how much? Normally the pill is like 98% effective when taken correctly. So does that drop to 95%? 90%? 50%? It's probably even worse if you are taking 2 antibiotics simultaneously, like some people (erg, like me). Anyone ever get pregnant while on the pill & taking antibiotics?

 

Yikes...

[CarnelianButterfly]

Just assume that it totally negates the effect of the pill and use another method. An exact percentage won't mean much of anything in this case. You don't want to get pregnant, so you just have to be more careful during that time.

 

BTW, you should also assume that the effectiveness is not restored for at least one whole cycle even if your antibiotic course is only one or two weeks long.

[HeartGoesOn]

I don't what the percentage rate of that happening is, but certain abx's do interact with bc pills.

 

I'm sure your MD can advise you more on that..Don't be afraid to ask.

[Roasted Carrots]

I think it pretty much just cancels out the pill. I was always told to use a back-up method or abstain until the antibiotics were finished.

[woebegone]

Actually I read there is no proof that the common antibiotics we use alter the Pill's effectiveness. Unless you're taking some heavy duty stuff, there should not as issue. I agree with Carnelian though. Assume the worst. Use backup methods while on antibiotics and for about a week afterwards. Can't hurt to be extra safe!!

[helplesslyhoping]

I don't know the specifics, but I can tell you what happened to me.

 

I was taking anti-biotics for strep throat. I took my birth control at the same time every day, I never skipped in all the years I took it.

I found out 1 1/12 months after my round of anti-biotics that I was 5 weeks pregnant.

 

Always back up for ONE FULL CYCLE OF PILLS AFTER YOU ARE DONE WITH THE ANTI-BIOTICS. One week or so won't cut it.

 

Always err on the side of caution unless you can handle the thing you are trying to prevent.

 

My daughters almost 9. Damn I'm glad I got strep!!

[CarnelianButterfly]

There are studies that show that the effectiveness with some antibiotics the reduction is minor, about 1% reduction of effectiveness. But that is an averaged estimation over a group of women, so for one specific woman her reaction could be to one extreme or the other, ie no change in effectiveness or significant loss of effectiveness. There is no way to know your exact response, so assuming the worst is best.

 

The antibiotic doesn't actually interact the medication itself, it effects the absorption of the compounds by the body. With low dose birth control the amount of hormones are so small that any change in your absorption could be enough to cause problems.

 

Medications known to effect birth control:

• Rifampin
  
• Penicillin
  
• Amoxicillin
  
• Sulfonamide
  
• Ampicillin
  
• Cotrimoxazole
  
• Tetracycline
  
• Griseofulvin
  
• Minocycline
  
• Phenobarbitol
  
• Metronidazole
  
• Nitrofurantoin
  

[woebegone]

Also I will just add that taking something as simple as a Tums antacid within a few hours of taking BC is not a good idea. There are so many little things that could potentially effect how your body absorbs the BC. That's why I think some form of backup should be used every single time. But that's just me.

[CarnelianButterfly]

Grapefruit juice is a notorious culprit for interfering with the absorption of anything from medication to even calcium.

[Tethys]

Ask the doctor who prescribed the antibiotics. Some have no effect on BC and some do. I always ask my doctor if they affect my BC. You really have to ask as doctors don't always tell you -- better yet, ask your pharmacist! They usually know.

[BellaDonna]

I had to take antibiotics this year while on the pill- my doc recommended that I use a back up method (condoms) while I was the antibiotics and for a week after as well.

 

It's just not worth the risk.

 

Just assume that it totally negates the effect of the pill and use another method. An exact percentage won't mean much of anything in this case. You don't want to get pregnant, so you just have to be more careful during that time.

 

 

Exactly.