Nitrofurantoin
"Never in my life have I taken such awful medication. Side effects after 1 tablet were headache, pain in eyes, dry mouth, sore throat, racing heart, insomnia, swollen hands, weakness like 
I'd been run over by a bus, depression, crying, anxiety. I carried on hoping things would get better but after 3 capsules the remaining 3 went in the bin. Never ever will I take these again"