Drug Levels and Effects:

Summary of Use during Lactation:

Limited information indicates that maternal doses of iohexol up to 45.3 grams (containing 21 grams ofiodine) produce low levels in milk. In addition, because iohexol is poorly absorbed orally, it is not likely to reach the bloodstream of the infant or cause any adverse effects in breastfed infants. Guidelines developed by several professional organizations state that breastfeeding need not be disrupted after a nursing mother receives aiodine-containing contrast medium.[1][2][3]

Drug Levels:

Maternal Levels.

Four mothers who were 1 week to 14 months postpartum received iohexol by rapid intravenous injection. Three received a dose of 50 mL (37.8 grams; 17.5 grams ofiodine) and one received 60 mL (45.3 grams; 21 grams ofiodine). Milk samples of 10 mL were collected 9 times over the 48 hours after the injection. The average iohexol milk concentration over the first 24 hours was 24.6 mg/L in the 3 women 1 week to 4 months postpartum and 130.5 mg/L in the one woman who was 14 months postpartum and weaning her infant. The authors calculated that the average amount of iohexol received by the first 3 infants over the first 24 hours would be 3.7 mg/kg or 0.5% of the weight-adjusted maternal dosage.[4]

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

Relevant published information was not found as of the revision date.

Possible Effects on Lactation:

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider:



1. American College of Radiology Committee on Drugs and Contrast Media. Administration of contrast media to breast-feeding mothers. In, ACR manual on contrast media. 2012;Version 8:79-80.
2. Webb JA, Thomsen HS, Morcos SK et al. The use of iodinated and gadolinium contrast media during pregnancy and lactation. Eur Radiol. 2005;15:1234-40. PMID:15609057
3. Chen MM, Coakley FV, Kaimal A, Laros RK Jr. Guidelines for computed tomography and magnetic resonance imaging use during pregnancy and lactation. Obstet Gynecol. 2008;112:333-40. PMID:18669732
4. Nielsen ST, Matheson I, Rasmussen JN et al. Excretion of iohexol and metrizoate in human breast milk. Acta Radiol. 1987;28:523-6. PMID:2960342

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Contrast Agents

  • Diagnostic Agents

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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