I think I've had an (extremely rare) side effect: gout.
I'd been taking prep for almost a full month, daily (rigidly). Then, out of nowhere I get a slight dull ache in my left big toe joint. Went away after a few hours. 2 days later, same feeling but stronger and lasted pretty much the whole day then calmed down. Early hours of day 4 searing pain, throbbing, swollen, red joint. Didn't know what the hell it was - just assumed a bunion. Saw Dr that afternoon: gout. I was shocked as I'm only 34 and otherwise really quite healthy (apart from having a six pack of beer, or bottle of wine twice or occasionally 3 times a week - more than recommended I know, but hardly excessive). Calmed down slightly after day 4, but still extremely uncomfortable and unable to walk in shoes, walk properly etc. Took prescribed meds after a couple more days after no improvement. Just over a week later almost back to normal.
Anyway, racking my brain as to how this could have happened (apart from alcohol/diet (again, fairly healthy)), I remembered that Truvada had a slight chance of affecting the kidneys (gout caused by kidneys being unable to fully clear uric acid from the blood). Searched Internet and found a study done in San Francisco a few years ago that found 0.08% of the sample group taking prep experienced gout, but only in a very narrow band: men 30-39 years old and taking it for a month or less. That helped me feel a bit better - but am taking no chances. Haven't drunk for almost 2 weeks, and plan to cut consumption by 80%+ and making appropriate changes to diet. Never want it again!
So, second months Truvada currently sitting unopened in the bathroom cabinet until I've excluded all possible causes.
Anybody heard of similar instances?