Bedtime versus breakfast L-thyroxine administration


  • Heather Mason
  • Univadis Medical News
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Adults with hypothyroidism may derive greater benefit by taking L-thyroxine medication at bedtime rather than before breakfast, a study in  Clinical Endocrinology  suggests.

The benefits from different timings of L-thyroxine administration remain controversial. The Chinese Society of Endocrinology recommends it be taken 60 minutes before breakfast, while the American Thyroid Association recommends it be taken either 60 minutes before breakfast or at bedtime. Studies conducted to determine the efficacy of L-thyroxine at different times have also been inconclusive. 

This systematic review and meta-analysis of 687 patients with hypothyroidism who were taking L-thyroxine, compared administration before breakfast or at bedtime.

Researchers found that L-thyroxine administration before breakfast compared with before bedtime (at least three hours after the evening meal) had no significant difference on thyroid-stimulating hormone level across studies (standardised mean difference [SMD] 0.09; 95% CI -0.12 to 0.3), and had no effect on free triiodothyronine (SMD -0.19; 95% CI -0.53 to 0.15).

A random-effect analysis performed on nine studies found that L-thyroxine administered at bedtime was associated with a higher free thyroxine level when compared with breakfast administration (SMD -0.27; 95% CI -0.52 to -0.02).

Thus, taking L-thyroxine at bedtime may be an attractive option for patients with hypothyroidism but further exploration is needed, the authors said.