I was prescribed the doxycycline hyclate 100mg twice daily for 21 days for lymes disease, I am on my 4th day, I had a hard time getting to sleep last night, I usually just fall to sleep in seconds. I am a 40 year sufferer of IBS "diarrhea", my worst time is usually in the morning, I noticed by the first day that my IBS symptoms were less severe and this morning I have been up for 4 hours and have not had to go yet.
I only negative side effect I have had so far is difficulty going to sleep, If it works to reduce or eliminate my IBS symptoms along with the lymes I can deal with the insomnia for a while.
I have been using probiotics for a while prior to starting on the doxy and the probiotics did seem to help with my IBS symptoms but not to this degree, I drink plenty of water with the doxy, so far I would have to say so good but it is early in the prescription so who knows, thank you to every one for posting your experiences with this drug