Doctors treat pyelonephritis with antibiotics. In most uncomplicated cases of pyelonephritis, the antibiotic can be given orally (by mouth), and treatment usually lasts for 10 to 14 days. Commonly used oral antibiotics include trimethoprim with sulfamethoxazole (Bactrim and others), ciprofloxacin (Cipro) or levofloxacin (Levaquin), but the choice of antibiotic will depend on your history of allergies and laboratory testing of the bacteria causing the infection. Once you finish the full course of antibiotics, your doctor may ask for another urine sample to check that bacteria are gone.
If you have high fever, shaking chills or severe nausea and vomiting, you are more likely to become dehydrated and may be unable to take oral antibiotics. In that case, you may require hospital treatment so that antibiotics can be given intravenously (into a vein). High fever and shaking chills also may be signs that your kidney infection has spread to your bloodstream and can travel to others parts of your body. If your doctor is concerned that you may have an obstruction (such as a kidney stone that is stuck in the ureter) or a structural abnormality in your urinary system, other tests may be ordered, such as a computed tomography (CT) scan or ultrasound.