How are you? Metoprolol side effects
usually include dry mouth, constipation
, heartburn, vomiting, diarrhea, decreased sex drive, impotence, or difficulty having an orgasm, headache, drowsiness, tired feeling, sleep problems or anxiety and nervousness. (ref: http://www.drugs.com/metoprolol.html) Nipple pain and tenderness have been documented but very rarely. Other factors that may have an effect may include hormone changes.