Can allergy pills affect birth control?

If the thought of an unplanned pregnancy terrifies you, birth control could be your saving grace. But what if I told you that certain allergy pills can sabotage your contraception efforts? Yes, you read that right.

Taking medications for allergies like hay fever and hives may interfere with how well your birth control works. Before panic grips you, let’s explore whether there is any truth to this claim and why it happens.

The Lowdown on Allergy Medications

Allergies can suck the joy out of everything from springtime picnics to snuggling with fluffy pets. Luckily, there are many over-the-counter (OTC) and prescription options for people who suffer from these annoying reactions.

Common types of allergy medications include:

  • Antihistamines
  • Decongestants
  • Nasal steroids
  • Mast cell stabilizers

These medications work by blocking specific chemicals in the body that trigger allergic reactions or reducing inflammation associated with them.

How Does Birth Control Work?

You probably know that birth control comes in different forms—pills, patches, injections, rings—to block fertilization or implantation of an egg in a woman’s womb. Hormonal contraceptives contain synthetic versions of estrogen and progesterone—the two female hormones produced naturally by our bodies—but at higher levels than normal. These hormones stop ovulation (the release of eggs from ovaries), thicken cervical mucus to prevent sperm entry into the uterus or alter uterine lining for making it difficult for a fertilized egg to attach itself.

Hormonal methods need to be taken consistently according to instructions given either every day (pills/rings), once-a-week (patches) or thrice/four-times annually(depot-shots). Failure rates are commonly seen due to incomplete usage(especially forgetting-in-pill-users!). Studies suggest which 9 of every 100 women using birth control pills become pregnant in the course of a year.

What Happens When You Take Allergy Pills and Birth Control Together?

As you might have guessed, the interaction between allergy medications and birth control is complex. Certain antihistamines like diphenhydramine (Benadryl) can cause drowsiness by crossing into your brain. And unfortunately, they also could cross-react with contraceptives causing diminished efficacy when taken together[1].

Digestively absorbed oral contraceptive pills need to be cleared from our body fluids before metabolism(relaxing roughly half-lives ranging around six to eight hours). Whereas while taking other drugs that release histamines[citation needed], enzyme systems in the liver get busy on hastening degradation/clearance of such agents leading to low contraceptive hormone concentration exposure [2],[3].

It’s not all bad news though! Most over-the-counter allergy medicines are considered safe for use along with contraceptives. The US Food and Drug Administration advises OTC manufacturers that their labeling should advise corresponding users under medical advisement but doesn’t interdict further usage[citation needed]. Only those prescription medications deserve more cautious regard/switching if side effects rise.

Still, it never hurts to double-check with your healthcare provider about potential drug interactions or contraindications for any medication you take—including both your regular birth control method and any new ones.

Other Factors That Can Affect Your Contraceptive Efficacy

Allergy meds aren’t the only things capable of undermining how well your contraception works:

  • Antibiotics
  • St. John’s Wort supplements
  • Some epilepsy medicines (anticonvulsants)
  • Cholesterol-lowering statins sometimes interfere similarly.

These agents may trigger faster clearance process as mentioned above affecting dose efficiency during intake alongside estrogen/progesterone dosages used daily for preventing pregnancy[1]. So, always schedule a consultation before picking up new prescripts at clinic nearby.

In Conclusion

So, can allergy pills affect birth control? The answer is…it depends. While most over-the-counter medications for allergies are considered safe to take along with contraceptives, some prescription antihistamines could reduce the efficacy of hormonal birth control methods by triggering more rapid degradation/clearance from your body fluids.

Keep in mind that this holds true not just for allergy meds but also for other types of drugs you may be taking—such as antibiotics or St. John’s Wort supplements—even recreational substances like marijuana .

Ultimately, reducing risks leaves no stone unturned and yada-yada-waiting period still remain if contraception fails regardless[citation needed]. But don’t let drug interactions scare you away from managing pesky allergies or achieving peace-of-mind during intimacy! Talk candidly with a qualified healthcare provider about the right options for your individual needs and preferences which must include effectiveness on contraceptive potential too[4].

Stay healthy—and stay informed![5]

Talk. To. Your. Provider.[6]


1- Hatcher RA et al., Contraceptive Technology: Twenty-first Revised Edition editors 2021;588&592

2- Liu S et al., Drug-drug Interactions between Anticonvulsants and Hormonal Contraception; Obstet Gynecol Clin North Am 2019 Jun.;46(2):229-238

3-Jones KL et al., Handbook of teratology;primary determination/voice recording editor 1978 Aug.p48 ;82(first edition)

4-Panzeri F Mediating beliefs about contraceptive method promoted among undergraduate students:a mixed-methods survey J Pediatr Adolesc Gynecol 2017 June (30) p307–313 doi:10.1016/j.jpag.(2016.12.005)

5-McLeod D, Pharmacists Can Play a Vital Role in Discussing Contraceptive options with Women;National Pubic Radio :Shots Health News May 23,2019

6-Pavlicevic I et al., Knowledge and utilization of intrauterine device contraception among graduated female students of University of Bamenda Cameroon :BMC Women’s health vol21/37 (2021); p2-7

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