Can doxycycline hyclate 100mg twice daily for 9 days cause distended abdomen. If so, is it a dangerous side effect, should I discontinue taking it?

Bloated. It's possible that 10 days of doxycycline caused abdominal bloating and it's worth asking your physician if you can safely discontinue it as he/she knows why it was prescribed and whether you need any more antibiotic treatment.As long as you don't have associated abdominal pain,vomiting or stoppage of bowel movement,there is no present danger.