Send to

Choose Destination
Nuklearmedizin. 2005 Feb;44(1):33-6.

Radioiodine uptake and thyroid hormone levels on or off simultaneous carbimazole medication: a prospective paired comparison.

Author information

Institute of Nuclear Medicine, University Hospital, Petersgraben 4, 4031 Basel, Schweiz.



To allow radioiodine (RAI) treatment in patients with need for anti-thyroid drug medication and low RAI uptakes we investigated the feasibility of discontinuing carbimazole for 3 days to enhance the RAI uptake without concurrent exacerbation of hyperthyroidism.


We prospectively investigated RAI dynamics and thyroid hormone concentration in 12 patients with low RAI uptake (<30%) under simultaneous carbimazole medication and 3 days after discontinuation. At both time points fT(4), T(3) and TSH were monitored.


Discontinuation of carbimazole for 3 days led to a significant increase of RAI uptake in all patients. We found an enhancement up to 4.9-fold compared to the measurement on carbimazole. The mean RAI uptake increased from 15.2 +/- 4.4% to 50.1 +/- 15.5% (p<0.001). The intrapersonal radioiodine half-life increased from 4.2 +/- 1.6 days to 5.4 +/- 0.7 days (p = 0.13). Mean thyroid hormone concentration was not affected by the three day withdrawal of anti-thyroid drugs and no patient suffered from an aggravation of biochemical hyperthyroidism.


A withdrawal of carbimazole for 3 days is long enough to provide sufficiently high RAI uptakes for RAI treatment in patients with low RAI uptakes and short enough to avoid the risk of exacerbation of hyperthyroidism.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Georg Thieme Verlag Stuttgart, New York
Loading ...
Support Center