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A component of the Canadian Medication Incident Reporting and Prevention System (CMIRPS).

SafeMedicationUse Newsletter

Am I Protected? Drug Interactions and Your Birth Control


medication interaction

Hormonal birth control medications, whether in the form of a pill, ring, patch, intrauterine device, or injection, are very effective in preventing pregnancy. Their effectiveness ranges from 93% (with typical use) to 99% (with perfect use). However, some medications and natural health products interact with these birth control methods, reducing their effectiveness.

Common medications that interact with hormonal birth control include antibiotics, antiseizure medications, and some natural health products. Taking these medications while you are on birth control can increase the chance of an unplanned pregnancy. learned about a person whose birth control pill was changed to a different product. This change caused the birth control pill to be less effective than the previous one, because of an interaction with a medication the person was also taking. The need for additional birth control precautions and the availability of other options to address the interaction were not explained to the individual. The result was an unexpected, life-changing pregnancy. has the following tips to help prevent a drug interaction with your hormonal birth control, as well as some actions to take if the interaction cannot be avoided:

  • Always tell your doctor or nurse practitioner, as well as your pharmacist, about all the medications you are taking. This includes prescription and nonprescription medications, vitamins, and natural health products. This information is especially important when you are starting any new medication or product.
  • If you need to take a medication that interacts with your birth control, ask your prescriber or pharmacist what alternative medications or other birth control options might be available. Sometimes an additional form of birth control is needed.
  • If you are unsure whether a product will interact with your birth control, ask your prescriber or your pharmacist. Alternatively, use a virtual health service (such as a telehealth service) to talk to a health care provider.

Medication safety bulletins contribute to Global Patient Safety Alerts

This newsletter was developed in collaboration with Best Medicines Coalition and Patients for Patient Safety Canada.

Recommendations are shared with healthcare providers, through the ISMP Canada Safety Bulletin, so that changes can be made together.

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