Hi doc. i was supposed to take cap doxcycline 100mg one tablet twice a day.i mistakenly took two tabs twice in a day(for just one day)...any effects?

Increase Side Effect: You could possibly experience an increase in any side effects such as headache, nausea, upset stomach, or diarrhea from an increased dose of doxycycline. Otherwise you should be okay but i recommend you still contact your health provider in case they wish to offer any more advice or follow-up.

Doxycycline: Likely upset stomach. Will be ok. Careful other meds could have been more serious.