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.
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.
Source: https://planb.ca/en/what-to-expect