CONSIDERATIONS
Plan B may also cause other temporary side effects, some of which may accompany the altered
menstruation or spotting
and be mistaken for changes to the period. These side effects may include nausea, tiredness, headache, dizziness, breast pain or vomiting, according to Drugs.com. Women who vomit within one hour of taking the Plan B tablet should contact a doctor, as the medication may not have not had time to work and they may not be protected against pregnancy.