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ISSUE 1 FEBRUARY
Letters to the Editor

Radiopharmaceuticals in breastfeeding

  • Giles Craig, Neil Hotham, Elizabeth Hotham

The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

 

Letter to the Editor

In the article on drugs in breastfeeding,1 I was dismayed at the inclusion of ‘radiopharmaceuticals’ in the table of drugs contraindicated in breastfeeding. There was little elaboration within the article as to the reason for this. The other drugs listed have sufficient evidence of the potential for serious adverse effects to the infant. This evidence simply does not exist for diagnostic radiopharmaceuticals.

Breastfeeding mothers regularly refuse timely diagnostic studies (to their detriment) on the basis of this misinformation touted by clinicians with little knowledge of radiology and risks. I kindly request that instead of ‘referring to the obstetric information service’ that you instead speak with the local nuclear medicine specialist.

Giles Craig
Radiologist and Nuclear medicine specialist
Barwon Health
Geelong, Vic.

 

Authors' comments

Neil Hotham and Elizabeth Hotham, the authors of the article, comment:

We thank Dr Craig for his comments and recognise that inclusion in the list of contraindicated drugs without qualification could be misleading. It is important for women to discuss any concerns with a specialist. In addition, there is sound advice available from the centres and references cited in our article.

It is essential to distinguish between radiopharmaceuticals. There is universal agreement that iodide (131I) is incompatible with breastfeeding, as the iodide concentrates not only in the maternal thyroid gland but also in breast tissue and breast milk. Permanent discontinuation is advised.2

For other radiopharmaceuticals, such as technetium, recommendations related to breastfeeding should be cognisant of the radioactive half-life of the pharmaceutical. For some, no interruption of breastfeeding is necessary, whereas for others, expressing breast milk for periods from 3–48 hours has been recommended (based on the individual isotope). Hale and Rowe advise that, for any radiopharmaceutical, the withdrawal period for higher doses should be a minimum of five half-lives of radioactivity and possibly up to 10.4

By comparison, for non-radioactive products such as gadolinium-based and iodinated contrast media, there is expert consensus that no interruption of breastfeeding is necessary.5 Despite this, the Australian product information for these products has a range of suspension recommendations from 24 hours (meglumine diatrizoate and sodium diatrizoate) to complete cessation (meglumine iothalamate). These examples highlight the pitfalls of relying on the product information in clinical practice.

 

References

  1. Hotham N, Hotham E. Drugs in breastfeeding. Aust Prescr 2015;38:156-9.
  2. Sisson JC, Freitas J, McDougall IR, Dauer LT, Hurley JR, Brierley JD. Radiation safety in the treatment of patients with thyroid diseases by radioiodine 131I : practice recommendations of the American Thyroid Association. Thyroid 2011;21:335-46.
  3. Siegel JA. Guide for diagnostic nuclear medicine. Reston (VA): Society of Nuclear Medicine; 2001. . .
  4. Hale TW, Rowe HE. Medications and mothers\u2019 milk. 16th ed. Amarillo (TX): Hale Publishing; 2014. .
  5. Royal Australian New Zealand College of Radiologists. RANZCR Guidelines for iodinated contrast administration. Sydney: RANZCR; 2009. .
  6. Chen MM, Coakley FV, Kaimal A, Laros RK. Guidelines for computed tomography and magnetic resonance imaging use during pregnancy and lactation. Obstet Gynecol 2008;112:333-40.
  7. Webb JA, Thomsen HS, Morcos SK. The use of iodinated and gadolinium contrast media during pregnancy and lactation. Eur Radiol 2005;15:1234-40.
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Drugs in breastfeeding Aust Prescr 2015;38:156-59
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Drugs in breastfeeding Aust Prescr 2015;38:156-59

Giles Craig

Radiologist and Nuclear medicine specialist, Barwon Health, Geelong, Vic.

Neil Hotham

Specialist editor

Elizabeth Hotham

Program director