Clinical application of the levothyroxine absorption test

Butt, Muhammad Arif; Gupta, Nidhi; Greenfield, Fiona; Waheed, Najeeb

doi:10.1530/endoabs.34.p52

Cited by 6 publications

(8 citation statements)

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“…Poor adherence to any medical therapy is a well-known treatment problem in chronic patients (17). Noncompliance to daily administration of LT4 is the most common reason for not responding to the appropriate dose of LT4 (18). "Pseudomalabsorption" due to intentional noncompliance as part of a psychiatric disorder should be considered as illustrated in the literature (11,14,16).…”

Section: Discussionmentioning

confidence: 99%

“…However, there is no gold standard for the LT4 absorption test, and various protocols have been advocated in the literature. The time commitment from a patient ranges from 2 hours to 5 days Test periods ranging from 2 hours to 5 days have been reported (18). We determined our loading test method by measuring FT4 and TSH in blood samples taken before and 1, 2, 3, and 4 hours after LT4 administration, and calculated the maximum FT4 increase.…”

Section: Discussionmentioning

confidence: 99%

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Refractory Hypothyroidism to Levothyroxine Treatment: Five Cases of Pseudomalabsorption

Elbasan

Yavuz

2020

Acta Endo (Buc)

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Context.A persistently elevated thyroid stimulating hormone (TSH) level is a common clinical problem in primary hypothyroidism patients treated with levothyroxine (LT4). "Pseudomalabsorption", which is characterized by poor adherence,should be considered in cases of refractory hypothyroidism after excluding other causes, such as malabsorption.Objective. We reviewed the features of the patients with persistently elevated TSH despite high-dose LT4 therapy.Design. Symptom evaluation, medications, comorbid diseases and physical examination features of five patients who applied to our outpatient clinic between 2016-2019 and diagnosed with LT4 pseudomalabsorption were retrospectively analyzed.Subjects and methods. The LT4 loading test was performed with an oral dose of 1,000 µg LT4. Demographic parameters, BMI, thyroid function tests, laboratory parameters for malabsorption were recorded.Results. We observed at least two-fold increase of free thyroxine levels during the test, which was considered pseudomalabsorption. Euthyroidism was achieved in two patients by increasing the LT4 dosage and in one patient with a change in the preparation. TSH decreased significantly after being informed about compliance in one patient. Another one was given LT4 twice weekly, but TSH remained elevated because of nonadherence.Conclusion. The LT4 loading/absorption test is a valuable tool to confirm the diagnosis of pseudomalabsorption. Informing patients, changing the preparation, increasing the dose, supervised intake of daily/weekly LT4 forms are treatment options for managing these cases.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Refractory Hypothyroidism to Levothyroxine Treatment: Five Cases of Pseudomalabsorption

Elbasan

Yavuz

2020

Acta Endo (Buc)

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“…We herein report a case of uncontrolled primary hypothyroidism due to L-T4 pseudo-malabsorption, documented by a normal L-T4 absorption test and by normalization of TSH following direct-observation L-T4 therapy. Nonadherence to LT4 daily administration is the most common reason for not responding to seemingly appropriate dose of LT4, ultimately leading to diagnosis of pseudo-malabsorption after proper testing (29) In contrast, a key characteristic of LT4 pseudomalabsorption is the patient's denial of poor adherence, leading to obvious challenges in diagnosis and management. 25,26 The L-T4 absorption test is an important tool to consider for distinguishing between nonadherence and true intestinal malabsorption (after excluding gastrointestinal and liver diseases, medication and dietary interference), the latter of which is very rare.…”

Section: Discussionmentioning

confidence: 99%

“…The time commitment from a patient ranges from 2 h to 5 days. 28–30 We elected to utilize a rapid, 2-h test. Adequate absorption of L-T4 was demonstrated with a subsequent prominent spike in free T4 plasma levels and concomitant suppression of TSH.…”

Section: Discussionmentioning

confidence: 99%

Levothyroxine pseudo-malabsorption: testing and treatment in the outpatient setting

Rdzak

Whitman

Inzucchi

2018

Therapeutic Advances in Endocrinology

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Persistent elevation of thyroid stimulating hormone (TSH) is a common clinical problem in outpatient clinics treating patients with primary hypothyroidism. One challenge to practitioners involves predicaments where patients have an inadequate response to a seemingly appropriate dose of levothyroxine (L-T4). A patient's self-assessed compliance to hormone replacement therapy or verification refill history at the patient's pharmacy might not be a reliable form of confirmation of non-adherence to the drug by the patient, which has been referred to as "L-T4 pseudo-malabsorption." A fast and inexpensive tool to rule out true LT4 malabsorption and thereby properly diagnosing and ultimately successfully treat LT4 pseudo-malabsorption is available in the outpatient setting. This allows clinicians to identify which patients for individual support in adhering to their prescribed therapy and may also reduce unnecessary referrals for sub-specialty care by endocrinologists.

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“…In patients with persistently elevated TSH levels, there are a number of causes, which needs to be considered, including poor administration and pathological malabsorption conditions. However, the literature is not clear on the actual degree of malabsorption, in each malabsorptive condition 11 .In the majority of the cases, the combination of history and examination identifies biological causes of LT4 malabsorption. Therefore, before more detailed investigations, the issue of adherence needs to be addressed 2 .…”

Section: Discussionmentioning

confidence: 99%

Levothyroxine Absorption Test in the management of a patient with persistent hypothyroidism

Monteiro¹,

Ferreira²,

Pires³

et al. 2018

Gal. Clin.

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Clinical application of the levothyroxine absorption test

Cited by 6 publications

References 0 publications

Refractory Hypothyroidism to Levothyroxine Treatment: Five Cases of Pseudomalabsorption

Refractory Hypothyroidism to Levothyroxine Treatment: Five Cases of Pseudomalabsorption

Levothyroxine pseudo-malabsorption: testing and treatment in the outpatient setting

Levothyroxine Absorption Test in the management of a patient with persistent hypothyroidism

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