I have a uti and my left kidney is now killing me i have keflex 500 mg should i take that instead of going to the er. i've taken 2 keflex 500 mg today

Kidney : Kidney infections, called pyelonephritis, are potentially deadly, particularly in the elderly. There are many bacteria that are resistant to keflex. A urine culture should sent before starting any antibiotic.

See below: If you have a kidney infection(pyelonephritis) you need to see a doctor and get a urinalysis and urine culture. You may need a renal ultrasound to be sure you do not have an obstruction with hydronephosis or renal stones. The Keflex you took might interfere with the urine culture.