RT Journal Article
SR Electronic
T1 Histamine Receptor 1 and 2 Antagonists Alter Biodistribution of Radioiodine
JF Journal of Nuclear Medicine Technology
JO J. Nucl. Med. Technol.
FD Society of Nuclear Medicine
SP 214
OP 219
DO 10.2967/jnmt.115.160697
VO 43
IS 3
A1 Oliver Edwards
A1 Ellen D. Yakish
A1 Li-Ming Wang
A1 Qi Wu
A1 John M. Hoffman
A1 Kathryn A. Morton
YR 2015
UL http://tech.snmjournals.org/content/43/3/214.abstract
AB Nuclear medicine technology assumes responsibility for examination-specific patient preparation procedures. This requires a clear understanding of the possible effects of medications on the outcome of examinations. There is evidence that common over-the-counter drugs, histamine 1 (H1) and histamine 2 (H2) receptor blockers and proton pump inhibitors, may directly or indirectly affect thyroid function. The objective was to determine whether short-term use of these drugs alters biodistribution of radioiodine in a rat model. Methods: Rats received no drug (controls) or daily subcutaneous injections of H1 blocker (promethazine), H2 blocker (famotidine), or proton pump inhibitor (esomeprazole) commencing 1 d before a single intraperitoneal injection of 0.037 MBq (1 μCi) of 131I (NaI) and continuing daily until euthanasia at either 1 d or 8 d after 131I. Organ uptake of 131I by control and drug-treated rats was compared by γ-well counting. Results: Promethazine significantly increased uptake of 131I by the thyroid (drug-treated–to–control ratios) both at 1 d (1.32) and 8 d (1.52) after 131I. Both famotidine and promethazine (respectively) significantly increased salivary gland uptake of 131I (drug-treated–to–control ratios) at 1 d (1.37, 1.40) and 8 d (4.52, 5.57) after 131I. Promethazine significantly increased gastric 131I uptake (drug-treated–to–control ratios) at 1 d (1.47) and 8 d (1.46) after 131I. Famotidine and promethazine (respectively) significantly decreased uptake of 131I by the liver (drug-treated–to–control ratios) at 1 d (0.60, 0.71) after 131I but resulted in a marked increase over control levels (11.21, 9.28) at 8 d. Blood levels of 131I were not altered by drug treatment. Esomeprazole did not affect radioiodine distribution. Conclusion: H1 and H2 blockers alter the biodistribution of radioiodine in the rat. Although the findings remain to be confirmed in humans, these drugs could increase radiation exposure to nontarget tissues, particularly the stomach and salivary tissue, during 131I therapy and consideration should be given toward avoiding the elective use of these drugs during radioiodine therapy.