Study Suggests Bedtime Might Be Best for Taking Levothyroxine

Taking levothyroxine for hypothyroidism at bedtime improves thyroid hormone levels compared with morning intake, according to an Archives of Internal Medicine study.

Some 100 patients were randomized to take levothyroxine at bedtime and placebo in the morning (30 minutes before breakfast), or placebo at bedtime and levothyroxine in the morning. After 3 months, they crossed over to the opposite treatment schedule for another 3 months.

Compared with morning treatment, bedtime levothyroxine lowered thyrotropin levels and increased free thyroxine and total triiodothyronine levels. Timing of treatment did not, however, affect several secondary outcomes, including quality of life.

The authors note that 30 minutes between morning treatment and breakfast might have been "too short to prevent interference with gastrointestinal absorption of levothyroxine." They conclude that clinicians should inform patients that bedtime levothyroxine is a good alternative to morning intake, as long as the drug is taken on an empty stomach.