Why Is The Contraceptive Pill Affected By Other Medicines
Some medications can cause oestrogen and progesterone levels to drop if youre taking the pill as well. Certain levels of these hormones are required to prevent ovulation, so lowering these may mean you are no longer protected from pregnancy.
The main culprits for causing oestrogen and progesterone levels to drop are enzyme-inducers. They speed up the processing of some contraceptive hormones, lowering levels of these hormones faster than normal, making them less effective. A wide range of medications contain enzyme-inducers, conditions that are often treated with enzyme inductors include epilepsy, depression and HIV, they are also often in treatments for sleep control, weight management, fungal control and even some natural remedies.
Both combined and mini pills are impacted by enzyme-inducers. Other hormonal contraceptive methods can also be affected, such as the patch, vaginal ring and implant. These all use synthetic versions of natural hormones which work together to prevent pregnancy by stopping ovulation. This prevents the fertilisation of an egg by sperm.
Contraception methods not affected by enzyme-inducers are the progesterone-only injection, the intrauterine device and the intrauterine system .
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Combined Hormonal Contraceptives Include:
- The pill
- The patch
- The ring
Combined hormonal contraceptives use multiple mechanisms to reduce the possibility of pregnancy. Estrogen suppresses the release of hormones from the pituitary. Progestin suppresses ovulation and thickens cervical mucus to prevent sperm from entering the upper genital tract. Progestin provides most of the contraceptive effects in hormonal contraceptive methods.
Will Emergency Contraception Like Plan B Work If I Am On These Medications
Emergency contraception like Plan B may not work if you:
-
Weigh over 165 pounds
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Take anti-seizure medications, antibiotics for TB, HIV medications, or St. Johns Wort
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Have recently used anti-seizure medications, antibiotics for TB, HIV medications, or St. Johns Wort
In these cases, the best method of emergency contraception is the copper IUD, for example, ParaGard. This will need to be inserted by a trained healthcare professional within 5 days of having unprotected sex. For more information about emergency contraception, see our blog post here.
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Im On Hormonal Birth Control Can I Get Pregnant If I Take Antibiotics
In most cases, no, as long as you continue to use your hormonal contraception as prescribed you are safe from pregnancy even if you are on antibiotics.
It is a myth that all antibiotics will interfere with the efficacy of your birth control pill.
There is however, one class of antibiotics that is the exception: rifamycins .
Antibiotics May Lessen Effectiveness Of Hormonal Contraception
Its safest to take extra precautions to avoid unintended pregnancy, advise researchers
Antibiotics may lessen the effectiveness of hormonal contraceptives, finds an analysis of unwanted side effects associated with the combined use of these drugs, and published in BMJ Evidence Based Medicine.
Women on the Pill should be advised to take extra precautions to avoid unintended pregnancy, when prescribed antibiotics, advise the researchers.
Suspicions that antibiotics, particularly those that cover a wide range of bacteria, known as broad spectrum antibiotics, might reduce the effectiveness of hormonal contraceptives, date back to 1973. Since then several anecdotal reports have also implicated various antibiotics in weakening the effects of hormonal contraceptives.
Current advice, which is based on a few small studies, is that antibiotics, other than those that prompt the production of certain enzymes, dont interfere with hormonal contraceptives.
To explore this further, the researchers drew on reports of suspected unwanted drug side effects, known as Yellow Cards, flagged up by clinicians and the public to the UKs drug and medical devices regulator, the Medicines and Healthcare products Regulatory Agency .
They compared the number of unintended pregnancies reported in 74,623 Yellow Cards for antibiotics in general and in 32,872 for enzyme-inducing drugs with those reported in 65,578 other types of drugs.
18/08/2020
Notes for editors
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How Can I Prevent Pregnancy If I’m Taking Antibiotics
It is not likely that you will get pregnant while taking antibiotics on the pill. But it doesn’t hurt to be extra cautious. To be safe, use a backup method of birth control while you take your antibiotics and for up to a week after you finish. Backup birth control options you can try include condoms, sponges and spermicide. You can buy these forms of birth control without a prescription at many grocery stores and drugstores.
Do not stop taking your birth control pills even if you are temporarily using a backup method of birth control. Take your pills exactly as you always have to avoid messing up your cycle.
What To Do If You Need To Take Antibiotics While On Birth Control
If your health care provider prescribes you an antibiotic and youre concerned about it affecting your birth control, simply use a backup form of birth control during and a week after treatment. These include:
- Condoms.
- A diaphragm .
- Spermicide .
- A cervical cap .
You might also talk to your medical team about switching to nonhormonal birth control, such as a copper intrauterine device . This small device can be placed in your uterus to prevent sperm from reaching and fertilizing an egg. The copper essentially acts as a spermicide.
If your health care provider prescribes you a rifamycin, always use a backup method of birth control, such as a condom or diaphragm, when having vaginal sex. Use one of these backup methods for the entire length of your treatment, plus a week after finishing the antibiotic.
If you are taking an antibiotic to treat a sexually transmitted infection such as gonorrhea or chlamydia, then you might need to avoid having sex during and immediately after treatment. Your Nurx medical provider can provide with the exact recommendations for each.
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What Other Types Of Drugs Can Alter Birth Control Effectiveness
Other drugs besides rifampin or the rifamycins may affect birth control reliability. Other drugs that induce enzymes can affect hormonal levels of your birth control and may lower its effectiveness.
Therefore, always have your doctor or pharmacist complete a drug interaction review any time you start or even stop a medication. This includes prescription medicines, as well as over-the-counter drugs, vitamin and herbal or dietary supplements.
For example:
- The antifungal medicine griseofulvin may lead to lower levels of birth control hormones and reduce the effectiveness of birth control pills.
- Certain seizures drugs can also lower the effectiveness of combined birth control pills, for example anticonvulsant medications such as:
- carbamazepine
- oxcarbazepine
- and barbiturates like phenobarbital
If youre taking any of these drugs use condoms as a backup form of birth control. Talk to your doctor about switching to a different nonhormonal method of birth control if youll be on these interacting drugs for a long time.
See Planned Parenthood for more information.
How Does Rifampin Interfere With Hormonal Contraception
Even though rifampin isnt so commonly prescribed, you might be curious about how it can interfere with the effectiveness of your birth control. The way this works is that rifampin lowers the concentration of estrogen in your blood plasma. It does this by increasing liver enzymes . Since combined oral contraceptives work by preventing ovulation through a combination of the hormones estrogen and progestin, decreasing estrogen hormone levels gets in the way of an important part of the pills function .
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Oral Contraceptive Steroid Pharmacokinetics
The estrogens most commonly found in oral contraceptive preparations are ethinylestradiol and mestranol, a prodrug which is metabolized to ethinylestradiol. After metabolism via the first pass effect, ethinylestradiol has an oral bioavailability of 40% to 50% . Hydroxylation is the main metabolic pathway for ethinylestradiol, whereas conjugation is considered to be a minor pathway in most women, resulting in sulphation or glucuronidation of the original estrogenic steroid. Glucuronide and sulphate conjugates reach the small intestine by way of the bile duct. Hydrolytic enzymes of intestinal bacteria break the conjugates down, resulting in the release of free, active estrogenic hormone. The active hormone is then available for reabsorption and undergoes enterohepatic cycling, which is responsible for plasma estrogen levels necessary for contraception.
The progestins present in oral contraceptive pills also undergo conjugation. Hydrolysis of conjugates leads to the formation of inactive metabolites because the parent molecule cannot be directly conjugated. Progestins are not thought to undergo extensive enterohepatic cycling and are, thus, less likely to be involved in drug interactions with antibiotics than ethinylestradiol .
How Do Antibiotics Affect Birth Control
Rifampicin affects the levels of contraceptive hormones present in the body, reducing the effectiveness of hormonal contraceptives.
There are several ways pills can interact with each other, and affecting gut absorption is just one of them. Rifampicin also changes the levels of some of the liver enzymes chemicals that can affect the way we use hormones in the body.
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Antibiotics That Do Not Affect Birth Control
Most antibiotics have no proven effects on hormonal birth control and will not increase your chances of getting pregnant if you have sex during treatment. Commonly prescribed antibiotics that are safe to take while on birth control include:
- Ampicillin, for treating bladder infections, pneumonia, and more.
- Cephalexin, for treating upper respiratory, ear, skin, urinary tract, and bone infections.
- Ciprofloxacin, for treating skin, respiratory, joint, and urinary tract infections.
- Clarithromycin, for treating bacterial skin and respiratory infections.
- Clindamycin, for treating skin, lung, soft tissue, vaginal, and pelvic infections.
- Doxycycline, for treating urinary tract infections, gonorrhea, chlamydia, syphilis, respiratory infections, and more.
- Metronidazole, for treating vaginal, stomach, liver, skin, joint, and respiratory system infections.
- Minocycline, for treating urinary tract, respiratory, and skin infections, as well as chlamydia.
- Ofloxacin, for treating skin infections, urinary tract infections, pelvic inflammatory disease, chlamydia, and gonorrhea.
- Roxithromycin, for treating bacterial respiratory tract, urinary and soft tissue infections.
- Sulfamethoxazole, for treating urinary tract, ear, and respiratory infections, among others.
- Tetracycline, for treating skin, respiratory, urinary, and other infections, as well as syphilis, gonorrhea, and chlamydia.
- And many more.
These medications are used to prevent the HIV virus from multiplying and keep it under control.
The Connection Between Antibiotics And Birth Control Pills
To date, the only antibiotic proven to impact birth control pills is rifampin. This drug is used to treat tuberculosis and other bacterial infections. If you take this medication while using birth control pills, it decreases the hormone levels in your birth control pills. This decrease in hormone levels can affect whether ovulation is prevented. In other words, your birth control becomes less effective. Rifampin also decreases hormone levels in the birth control patch and vaginal ring.
Other drugs may make birth control less effective, such as:
- some anti-HIV protease inhibitors
- some anti-seizure medications
- the antifungal drug griseofulvin
Birth control pills may make other drugs less effective, such as analgesics and blood pressure medications. The effects of antidepressants, bronchodilators, and tranquilizers may be increased when you use them with birth control pills.
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How Do Antibiotics Affect Birth Control Pills
The birth control pill, commonly called the pill,” is a medication women take once a day to prevent pregnancy. One way birth control pills prevent pregnancy is by preventing ovulationwhen your body releases an egg that can be fertilized by a male sperm. Some antibiotics can interfere with your menstrual cycle, causing you to ovulate even though youre on the pill.
Where Are They Stored
We know that when it comes to storing food and such items, it is very important that they it is done appropriately. This is to prevent food from rotting or going bad two things that can make you very sick when you eat them. Did you know the same goes with birth control? If birth control is stored incorrectly, then it can be rendered ineffective and might as well be thrown out.
Birth control pills must be stored appropriately. They do not belong in the freezer or anywhere that gets cold and damp. They should be always kept at room temperature. Condoms should be stored away from anything sharp. If you keep your stash in a bedside drawer or a bathroom drawer, make sure nothing sharp is near them. This can include safety pins, needles and even razors. A needle can make a hold that is small enough to avoid sight but is large enough for sperm to exit through.
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Are There Any Side Effects Of Taking Birth Control And Antibiotics
Since most antibiotics and birth control pills don’t interact, there isn’t data that demonstrates side effects unique to taking them together. The exception is if you’re taking rifampin, which can increase the chances of experiencing an unwanted pregnancy due to its impact on the effectiveness of birth control pills.
On their own, birth control pills have some potential side effects that may, theoretically, be more likely if the antibiotic you’re taking has similar potential side effects. These include:
- headaches or dizziness
- a change in your usual appetite
- diarrhea
- nausea or vomiting
Another common side effect of birth control pills is breakthrough bleeding, also known as spotting. Some bleeding between periods is pretty common, and hormonal birth control can increase your likelihood of experiencing it. Aside from the unfortunate fact of ruining another pair of underwear, it’s usually not something to be concerned about.
One of the causes of spotting can be missing a pill or taking it at irregular intervals. When you start your course of antibiotics, make sure you keep taking your contraceptive at the same time to reduce the likelihood of breakthrough bleeding.
Women Can Have Two Uteruses Seriously
Through all the reasons why birth control may not work, most of them are due to usage error or environmental factors. There is one case where a womans own body may mean that birth control does not work. There are a number of women out there who are born with Uterus Didelphys. This means that they are born with two uteruses, two cervixes or two vaginas, or a combination of a couple of these. They have not been able to point out exactly why this happens, or how to prevent it from happening, but it can impact the accuracy of your birth control.
Your best bet for accurate birth control when you have two uteruses is to use condoms, as that stops the sperm from even entering. The birth control pill may still be effective, but it would involve a conversation with your doctor. A lot of women opt to get an implant birth control, like an IUD. This is not a preferred method of birth control for a woman with two uteruses, because they can often not fit one in each uterus, so there is still a chance of the vacant uterus creating a pregnancy.
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Other Bacteria And Protozoans
In 2008, tentative evidence showed rifampicin may be useful in the treatment of methicillin-resistant Staphylococcus aureus in combination with other antibiotics, including in difficult-to-treat infections such as osteomyelitis and prosthetic joint infections. As of 2012, if rifampicin combination therapy was useful for pyogenic vertebral osteomyelitis was unclear. A meta-analysis concluded that adding adjunctive rifampicin to a -lactam or vancomycin may improve outcomes in staphylococcus aureus bacteremia. However, a more recent trial found no benefit from adjunctive rifampicin.
It is also used as preventive treatment against Neisseria meningitidis infections. Rifampicin is also recommended as an alternative treatment for infections by the tick-borne pathogens Borrelia burgdorferi and Anaplasma phagocytophilum when treatment with doxycycline is contraindicated, such as in pregnant women or in patients with a history of allergy to tetracycline antibiotics.
It is also sometimes used to treat infections by Listeria species, Neisseria gonorrhoeae, Haemophilus influenzae, and Legionella pneumophila. For these nonstandard indications, antimicrobial susceptibility testing should be done before starting rifampicin therapy.
The Enterobacteriaceae, Acinetobacter species, and Pseudomonas species are intrinsically resistant to rifampicin.
It has been used with amphotericin B in largely unsuccessful attempts to treat primary amoebic meningoencephalitis caused by Naegleria fowleri.
How Long Does It Take For The Birth Control Implant To Work
If you get Nexplanon during the first 5 days of your period, youre protected from pregnancy right away.
If you get the implant at any other time in your cycle, use some other form of birth control during the first week. After that first week, the implant starts working and youre protected from pregnancy for up to 5 years. Thats why its called get-it-and-forget-it birth control.
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Factors That Make The Birth Control Pill Less Effective
Medically reviewed by Kristin Hall, FNP
Used perfectly, the birth control pill both combined and the progestin-only kind are 99 percent effective at stopping you from becoming pregnant.
However, a range of factors can make birth control less effective than normal. From your use of other medications to digestive disorders, both your habits and your general health can affect the effectiveness of the birth control pill.
Weve listed five of these factors below, along with what you can do to make sure birth control works the way it should for you.
