Full report on a survey of adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan.

Objective: This pharmacovigilance-based survey was aimed at determining the prevalence of, and association between, radiopharmaceuticals and adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan.

Methods: The Subcommittee for Safety Issues of Radiopharmaceuticals of the Japan Radioisotope Association's Medical Science and Pharmaceutical Committee mailed a form for reporting adverse reactions to radiopharmaceuticals to all institutes performing nuclear medicine examinations in Japan. This investigation included adverse reactions to diagnostic radiopharmaceuticals labeled with both single-photon- and positron-emitting radionuclides and therapeutic sodium iodide labeled with I. Each institute returned the reporting form to the subcommittee each time an adverse reaction occurred.

Results: Replies were obtained from 75% of the institutions. In total, 1099 adverse reactions were reported from 46,645,580 radiopharmaceutical administrations, giving a prevalence of 2.4 adverse reactions per 100,000 administrations (95% confidence interval 2.2-2.5). Adverse reactions were most frequently observed for I-iodomethylnorcholesterol (230.1/10 administrations), followed by I-HSA (76.3/10 administrations), I-sodium iodohippurate (31.2/10 administrations), and Tc-DTPA (12.0/10 administrations). Comparison of adverse reactions between before and after 1997 revealed that prevalence dropped from 3.7/10 administrations (95% confidence interval 3.5-4.1) to 1.5/10 administrations (95% confidence interval 1.4-1.6). During the study period, vasovagal reactions accounted for 50.3% of adverse reactions, fever for 7.5%, allergic reactions for 25.7%, and other for 16.5%; 3.7% of all adverse reactions were considered severe but none were lethal. A definite, probable, possible, less likely, and uncertain causal relationship with radiopharmaceuticals was observed in 13.1%, 33.7%, 39.9%, 6.2%, and 7.1% of adverse reactions, respectively.

Conclusions: These results suggest that nuclear medicine staff must be aware of the possibility of adverse reactions from radiopharmaceuticals, despite their rarity.