Contrast Agent Administration Guidelines

Patient Selection and Preparation

Patients with significant volume overload (edema or ascites) should avoid iohexol, as recommended by the Kidney International guidelines 1
A 7-day waiting period is recommended after iodinated contrast administration before undergoing an iohexol mGFR test to ensure complete washout, according to the Kidney International guidelines 1
Iohexol administration should be avoided during acute illness that may transiently affect GFR, as suggested by the Kidney International guidelines 1
Patients with certain conditions may need to stop metformin prior to iohexol administration, and general guidance on minimizing contrast dose and maintaining adequate hydration should be followed, as recommended by the Kidney International guidelines 1

The overall rate of adverse events with iohexol for GFR measurement is very low (0.0066%), according to the Kidney International guidelines and the American College of Radiology 1
High-risk patients with documented severe reactions to iodinated contrast media may require premedication with antihistamines or corticosteroids and close monitoring, as recommended by the American College of Radiology 2

Shellfish allergy is NOT a contraindication for iohexol use, as shellfish allergies are due to tropomyosin, not iodine, as stated by the Kidney International guidelines and the American College of Radiology 1
"Iodine allergy" is scientifically inaccurate, as iodine is an essential nutrient that cannot be recognized as an antigen by the immune system, according to the Kidney International guidelines and the American College of Radiology 1
Allergies to povidone-iodine (topical antiseptic) are not contraindications for iohexol, as recommended by the Kidney International guidelines and the American College of Radiology 1
Asthma or COPD do not require premedication before receiving iohexol, according to the Kidney International guidelines and the American College of Radiology 1

The incidence of anaphylactoid reactions to contrast media is approximately 1%, with severe reactions occurring in only about 0.04% of cases, and recurrence rates without prophylaxis range from 16% to 44%, but can be reduced to nearly zero with appropriate premedication, as reported by 3
Premedication is strongly recommended (Class I recommendation) for patients with prior contrast reactions, and standard premedication regimens include:
Non-contrast CT angiography, MR angiography, and ultrasound with Doppler may be considered as alternative imaging options for select patients, as recommended by the Kidney International guidelines and 3, 1
Only patients with documented severe anaphylactic reactions to iodinated contrast media warrant special consideration, and should be treated with caution, as recommended by the American College of Radiology 4
For patients with previous reactions to contrast media, consider using iohexol or other non-ionic contrast media at the lowest possible dose, as recommended by the American College of Radiology 2