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Use of oral liquid thyroxine to avoid uptake interference from other drugs

Here is an interesting paper which examines the use of oral liquid thyroxine to avoid uptake problems by other drugs taken at the same time. Unfortunately I can only access the abstract.

Oral liquid levothyroxine solves the problem of tablet levothyroxine malabsorption due to concomitant intake of multiple drugs

Article in Expert Opinion on Drug Delivery · February 2017

DOI: 10.1080/17425247.2017.1290604

Roberto Vita · Università degli Studi di Messina

Flavia Di Bari

Salvatore Benvenga


Background: Unlike its tablet (TAB) formulation, liquid L-T4 (LIQ) is directly absorbed in the intestine. The aim of this study was to assess whether LIQ was superior to TAB, such that it would overcome the interference induced by co-ingestion of multiple interfering drugs (ID). Methods: In this prospective cohort study, we recruited 11 patients with apparent reduced TAB absorption due to ≥2 ID, and switched them to LIQ while maintaining the daily dose and the co-ingestion of the ID. Serum TSH was assayed at least twice every eight weeks. Results: Serum TSH was significantly lower on LIQ compared with TAB (P<0.0001), in patients who took L-T4 for either replacement (P=0.002) or TSH-suppression (P<0.0001). This difference was evident already at the first measurement post-switch (P=0.008 or P=0.03). Regardless of the purpose of L-T4 therapy, patients who took two ID had lower serum TSH on LIQ compared with patients who took three ID (P=0.0006). Interestingly, 2/3 patients who failed to reach target TSH levels while on LIQ took three ID. Conclusions: LIQ overcomes the concurrent interference exerted by the ingestion of multiple ID. In such cases, switching from TAB to LIQ permits patients to reach target TSH within 8 weeks.

This may answer some questions about the circumstances when T4 pills don't work well.

3 Replies

But how good was their free T3? If it just drops TSH like a stone it might be counter productive for those whose GPs dose on TSH only.


If T4 gets into circulation better, then FT3 must benefit.


You'd hope so, but I had an FT4 over 18 at one point and FT3 right at the bottom of the range.


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