I started taking doxycycline two weeks ago for lyme. I take 200mg in the morning.
I don't get stomach problems, but I get major motion sickness issues starting about 30 minutes after taking it and lasting until about 2 hours after taking it. If I lie down with my eyes closed, I have no problems, but if I try to watch TV or use my laptop, I end up vomiting rather enthusiastically. Food is supposed to help if there's a stomach issue, but since my issue is entirely neurological, having food in my stomach just makes me feel a lot more serious about throwing up.
So when I wake up at 6am to use the bathroom, I then go take the doxy, wash it down with a full glass of water, and go back to bed for a couple hours to sleep it off. Then I feel pretty decent for several hours until I take another antibiotic and the hypotension hits
