What to expect from Plan B®

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When did you have sex

without a contraceptive or have a contraceptive accident?

Please select a time earlier than the present.

You have hours remaining to take Plan B®.

The sooner you take Plan B®, the better it works. Plan B® can help prevent pregnancy if taken within 72 hours, and preferably within 12 hours, after a contraceptive accident or unprotected sex.

It has been more than 72 hours since you had unprotected sex or a contraceptive accident. Please contact a healthcare professional for advice.

Plan B® is effective

Although few women experience vomiting with Plan B®, if you vomit within two hours of taking Plan B®, you might not have absorbed the medication contained in the pill. Call your healthcare professional, as you might need another dose.

After you’ve taken Plan B®, you should get your next period at the expected time, or a few days early or late. You may experience spotting a few days after taking Plan B®, but this is not your period.

While you’re waiting for your next period, abstain from having unprotected intercourse or make sure to use a contraceptive.

If you’ve taken Plan B® because of missed birth control pills, start your birth control pills right away and remember to use another method of contraception, such as condoms, until your birth control is fully reliable again.

95% effective when treatment is taken within 24 hours of unprotected sex.
If your period is more than a week late, or you haven’t had a period within three weeks of taking Plan B®, it is possible that you’re pregnant. Talk to your doctor and have a pregnancy test done.
Good to know: Tell your doctor if you have taken Plan B® within three days of a Pap test, as it may affect your results.

For any questions, you can call the Plan B® medical information line at 1‑888‑919‑0782 (Canadian residents only).

Side effects of the morning-after pill

It’s very unlikely that you will have any severe reactions to Plan B®. You may have some temporary side effects that will usually pass within 24 hours.

Most common Plan B® side effects

Like all medications, Plan B® can cause some side effects:

  • Nausea: ~14% to 23% of women
  • Abdominal pain: ~18% of women
  • Fatigue: ~17% of women
  • Headache: ~17% of women
  • Dizziness: ~11% of women
  • Breast tenderness: ~11% of women
  • Vomiting: ~6% of women
  • Diarrhea: ~5% of women
  • Irregular menstrual bleeding: Some women may experience spotting after taking Plan B®. The majority of women will have their next menstrual period at the expected time or early. When Plan B® is used repeatedly (more than once in a menstrual cycle, or more than occasional once-a-month use), menstrual changes may occur, including a shorter or longer cycle and a heavier or lighter period than normal.

These side effects usually do not last more than 24 hours.

Less common Plan B® side effects

Migraine or severe headache, lower abdominal pain, painful menstruation and vaginal discharge. If your period is more than a week late or if the symptoms persist for more than 48 hours or are severe, see your healthcare professional.

Unusual side effects—call a healthcare professional immediately

  • Itching and a rash
  • Sudden or unusual cramping or severe pain in your stomach or belly prior to your next normal period
  • Uterine hemorrhage
  • Vaginal hemorrhage
  • Any effects that persist or worsen
  • If you vomit within two hours of taking Plan B®, you may need to take another dose

Some medications can interact with Plan B® and make it less effective. These include anti-HIV drugs (efavirenz and ritonavir), anticonvulsant drugs (phenytoin, carbamazepine, primidone and phenobarbital), antibiotics (ampicillin, cotrimoxazole, tetracycline, temafloxacin, and clarithromycin), rifampicin, rifabutin, griseofulvin, St. John’s wort, and ulipristal acetate.

There are some medical conditions that may mean Plan B® is not right for you. Plan B® is not recommended if:

  • You have a confirmed or suspected pregnancy
  • You are allergic to levonorgestrel, or to any of the ingredients in the formulation
  • You have abnormal vaginal bleeding

For more details, download the abbreviated Plan B® Product Monograph (Part III):

Product Monograph (Part III): Plan B® 1.5 mg