Actually, I-123 IS radioactive.  Hale's book has an appendix listing
radio-therapeutic drugs, and it depends on the doe as to how long
nursing must be interrupted.

But Optiray is just an iodinated contrast agent, and there is no need to
pump and dump at all...<0.1% of these compounds is absorbed orally, so
what little gets into the milk is not absorbed by the baby.  Dr Newman
shared a letter with me that I modified and sent to our radiologists,
who are still telling moms to pump and dump for 48 hours.  That
recommendation probably comes from the package insert.

 I will cut and paste below:


<<...I would encourage you to consider examining your policies regarding
breastfeeding mothers and IV contrast media based on the following
points:

Concerning CT scans (and other studies using radioopaque contrast media
containing iodine):

1.      We do these contrast studies in infants, using the same
radioopaque substances (CT scan, IVP etc)
2.      Iodine compounds are felt by some to be a contraindicated during
breastfeeding, but in these contrast media, the iodine is covalently
bound to the organic molecule and is metabolically stable and
essentially not bioavailable.  For the most part, these organic
radiocontrast agents are rapidly excreted without significant metabolism
and the amount of elemental iodine released is minimal.  Virtually all
these agents have very short plasma half lives (< 2 hours) and milk
concentrations are extremely low.  Moreover, of the minimal amount in
the milk,  <1% is absorbed by the infant.
3.      Specific data exists on Iohexal(1).  In 4 women who received
0.775 g/kg (350 mg iodine/ml) of iohexal IV, the mean peak level of
Iohexal in milk was 35 mg/L at 3 hours post-injection.  The average
concentration in milk was only 11.4 mg/L over 24 hours.  Assuming a
daily milk intake of 150 ml/kg body weight, the amount of Iohexal
transferred to an infant during the first 24 hours would be 1.7 mg/kg
which corresponds to 0.2% of the maternal dose.
4.      Milk levels are similar for Iopanoic acid, Metrizamide and
Metrizoate.

Magnetic Resonance Imaging using Gadopentetate (Gadolinium) as the
contrast material:

1.      The American Academy of Pediatrics considers this drug
compatible with continued breastfeeding. (Which, in my opinion, is an
extremely conservative list.)
2.      In one study (2), the cumulative amount excreted from both
breasts in 24 hours was only 0.023% of the administered dose.  Oral
absorption of gadopentetate is only 0.8% of that ingested.  Thus the
amount the baby would get from a single dose is insignificant (0.013
micromole of a gadolinium containing compound would be absorbed by the
baby in 24 hours).
3.      The half life of gadopentetate is 1.6 hours.  Thus 98% would be
excreted from the mother in 5 half lives or 8 hours.  So even if it were
absorbed, why 24 hours?  Why 48 hours?
4.      Gadopentetate is used in small babies, some premature.
5.      In another study (3) of 19 lactating women who received 0.1
mmol/kg and one additional woman who received 0.2 mmol/kg, the
cumulative dose of gadolinium excreted in breastmilk druing 24 hours was
0.57 micromole.  A similar amount was observed in the patient receiving
the double dose.  According to the authors "the very small amount of
gadopentetate transferred to the nursing infant does not warrant a
potentially traumatic 24 hour suspension of breastfeeding..."

Given the above, I do not understand the reasoning behind prohibiting
continued breastfeeding. I assume perhaps the current recommendations
are in line with the manufacturers' recommendations, however the
manufacturers are primarily concerned about their own liability, not
what is actually best for mothers and babies.  Please inform mothers
that the scientific data does not support interruption of breastfeeding,
or refer them to me at MilkWorks if you prefer.  If you would be
interested, I have drafted hand-outs about common post-op medications
for a local outpatient surgical center, and would be happy to do so for
IV contrast agents if it would be helpful to you.

Sincerely,


Kathy Leeper, MD, IBCLC
Medical Director, MilkWorks

1. Nielsen ST, et al. Excretion of iohexol and metriozate in human
breast milk. Acta. Radiol  28:523-26, 1987
2.Rofsky NM, et al. Quantitative analysis of gadopentetate dimeglumine
secreted into breastmilk. J Magnetic Resonance Imaging 1993;3:131
3.Kubik-Huch RA, et al. Gadopentetate dimeglumine excretion into human
breastmilk during lactation. Radiology 2000;216(2);555-8  >>

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