Lisinopril
"I started taking lisinopril a week ago on Saturday, that same day I started getting lower back pain, I didn't attribute the pain to the drug till a week later.  The pain in my lower back was so extreme I could hardly walk or sleep, so I went to prompt care on Wednesday thinking it might be a UTI, Test was negative, doctor ordered PT. Next day I ended up in ER, bp was extremely high, rapid heart rate, felt like I was gonna pass out, all tests were negative, doctor said it was the new med and dehydration. I called my primary, I told her about the symptoms I was having, she said back pain wasn't a side effect of this drug, and the other symptoms were my body getting used to the drug."