i know that some medicines when you begin them can give you nausea. i take tow medications and it took me a good 2 weeks to get over the nauseous feeling that the medicine gave me upon starting. it was horrible. i also know that if the pharmacy switches manufactures of your medication this can cause the body to readjust and may cause nausea. My pharmacy did this and again ...it was like starting the medication from scratch with nausea! however, ... if you are feeling nausea and have started a medication and have ruled out pregnancy ... this may be a reason.