Pyelography is considered mostly safe. The major risk is a reaction to the iodine-based dye.
Minor reactions include hot flashes, nausea and vomiting. These can often be treated well with antihistamines. There’s also a chance of urinary tract infection or pain.
In very rare cases, more severe reactions can occur. These include:
- Trouble breathing
- Low blood pressure
- Swelling of the mouth or throat
- Heart attack
Be sure to tell your doctor and the radiologist about your history with allergies.