Which medication should be discontinued on the day of IV iodinated contrast exposure?

Which medication should be discontinued on the day of IV iodinated contrast exposure?

• A. Metformin
• B. Amlodipine
• C. Gabapentin
• D. Phenytoin

Answer: (A)

Holding metformin around IV iodinated contrast is essential because the contrast can temporarily impair kidney function, reducing metformin’s excretion. If metformin accumulates when renal function is affected, there’s a risk of lactic acidosis, a serious complication. That’s why it’s stopped on the day of contrast exposure and for a period afterward (commonly 24–48 hours, then resumed once renal function is stable). The other medications listed don’t carry the same acute risk with contrast and don’t require discontinuation solely for a contrast study.

Holding metformin around IV iodinated contrast is essential because the contrast can temporarily impair kidney function, reducing metformin’s excretion. If metformin accumulates when renal function is affected, there’s a risk of lactic acidosis, a serious complication. That’s why it’s stopped on the day of contrast exposure and for a period afterward (commonly 24–48 hours, then resumed once renal function is stable). The other medications listed don’t carry the same acute risk with contrast and don’t require discontinuation solely for a contrast study.