Keflex was not as bad as I thought it would be since I had recently been on Doxycycline which was torture.
I was put on Keflex for a UTI. I took 500mg 4 x a day for 12 days.
I experienced ringing in my ears which was tolerable because it was intermittent.
I had a continuous low-grade headache. When the headache would get worse I would take Advil, which would reduce it to low-grade again - it hardly ever went away completely until I was done the Keflex.
I also had diarrhea which is common with antibiotics. This too was tolerable.
I was nauseous pretty much the whole time but did not vomit.
The thing that bothered me the most is the way my body would feel like it was buzzing. My head would feel weird. And sounds such as running water in the sink, vacuum cleaner, rain on the windshield, etc, felt so loud and like a horrible rushing in my head.
It is a little hard for me to distinguish what was caused by the Keflex, or what was caused by the UTI, or the Endometriosis I might have, as well as the Doxycycline I had been on left some lasting effects.