CKD-EPI 2021 eGFR with contrast / metformin / gadolinium guidance, a steroid premedication scheduler, and breastfeeding guidance.
Renal function — eGFR
CKD-EPI 2021 creatinine equation (race-free).
mg/dL
—mL/min/1.73m²
Steroid premedication
For a prior allergic-like or unknown-type reaction to the same class of contrast (iodinated → iodinated, gadolinium → gadolinium). A prior severe reaction is a relative contraindication to re-exposure to that class. Not indicated for shellfish/iodine allergy, asthma, or a reaction to the other contrast class. Pick a regimen and the scan time.
Set a scan time to generate the schedule.
Breastfeeding after contrast
For a lactating parent asking whether to interrupt nursing. Pick the agent given.
eGFR thresholds (ACR Manual on Contrast Media).
Routine IV iodinated contrast in outpatients with a stable eGFR ≥ 30 and no AKI carries very low AKI risk and needs no special prophylaxis.
Prophylaxis (IV volume expansion with isotonic saline) is indicated for patients with AKI or eGFR < 30 — AKI is an independent trigger, and creatinine-based eGFR is unreliable while renal function is changing.
Metformin: no need to withhold if eGFR ≥ 30 and no AKI; withhold at the time of contrast and for 48 h if eGFR < 30, AKI, or the study is on the renal arteries / arterial study with possible emboli, then resume after renal function is confirmed stable.
Gadolinium (GBCA): group II agents (e.g., gadoterate, gadobutrol, gadobenate) carry very low NSF risk at any eGFR; group I agents are contraindicated in at-risk patients (AKI, or eGFR < 30 / CKD stage 4–5).
Premedication. Considered for a prior allergic-like or unknown-type reaction to the same class of contrast medium; a prior severe reaction is a relative contraindication to re-exposure to that class. Two elective oral regimens are considered similarly effective: (1) prednisone 50 mg PO at 13, 7 and 1 h before contrast + diphenhydramine 50 mg 1 h before; (2) methylprednisolone 32 mg PO at 12 h and 2 h before contrast (an antihistamine may be added). If the patient cannot take oral medication, substitute hydrocortisone 200 mg IV for each oral steroid dose.
Accelerated IV (urgent only, unproven benefit): methylprednisolone 40 mg IV (or hydrocortisone 200 mg IV) immediately, then every 4 h until contrast + diphenhydramine 50 mg IV 1 h before — usually 4–5 h in total. Regimens shorter than 4–5 h (oral or IV) have not been shown to be effective.
Breastfeeding. Patients may continue breastfeeding without interruption after both iodinated and gadolinium contrast; pump-and-dump is not required. Estimated infant dose < 0.01% of the maternal IV dose for iodinated agents; for gadolinium < 0.04% is excreted into milk in 24 h and < 1% of that is absorbed.
Reference only — not a substitute for clinical judgment or your local contrast policy. Based on the ACR Manual on Contrast Media.