Utility of a Liquid Formulation of Levo-thyroxine in Differentiated Thyroid Cancer Patients

Efficacy and safety of postoperative levothyroxine sodium tablets for improving serum thyroid hormone levels and tumor marker levels in patients with thyroid tumors

Levothyroxine tablet has been used for improving serum thyroid hormones. Despite its efficacy, there has been a persistent recurrence. We aimed to evaluate the efficacy of levothyroxine regimen (administered as sodium tablets or liquid) therapy, including the regime in combination with other thyroxine hormones, to determine its effectiveness and safety regarding thyroid tumor patient outcomes. An electronic search of the online databases (PubMed, EMBASE, and Web of Science) was performed in duplicate independently by two authors (SSK and LPY) to identify any potential studies published in the English language from January 2002 to October 2022. The records were retrieved using keywords and MeSH terms. The Cochrane risk of bias tool in the Review Manager (RevMan software version 5.4.) was used to evaluate the risk of bias in the included studies.  A total of 18 quality studies were reported on levothyroxine tablets. Results showed that liquid levothyroxine was more efficient than tablet levothyroxine. Further results showed that levothyroxine in combination with L-T3 or I-131 was more effective than L-T4 tablet monotherapy for improving thyroid cancer hormones. Levothyroxine tablet monotherapy is less efficient than liquid levothyroxine and/or levothyroxine combined therapy. This research recommends future research using larger randomized controlled studies.

Seeking optimization of LT4 treatment in patients with differentiated thyroid cancer

Levothyroxine sodium (LT4) is the mainstay treatment to replace thyroid hormonal production in thyroidectomized patients, but, depending on the aggressiveness of the cancer and on the risk of recurrence, patients with differentiated thyroid cancer may also be treated in a TSH-suppressive or semi-suppressive mode. The pathophysiological rationale for this LT4 treatment stems from the role of TSH, considered to be a growth factor for follicular cells, potentially inducing initiation or progression of follicular cell-derived thyroid cancer. Therefore, accurate tailoring of treatment, taking into account both patient characteristics (age and comorbidities) and risk of persistent/recurrent disease, is highly recommended. Furthermore, adjustments to traditional LT4 treatment should be made in thyroidectomized patients due to the lack of thyroidal contribution to whole body triiodothyronine (T₃) concentration. Since LT4 exhibits a narrow therapeutic index and the side effects of over- and under-treatment could be deleterious, particularly in this category of patients, caution is required in dose individualization, in the mode of ingestion, and in potential pharmacological and other types of interference as well. Our aim was to analyze the current knowledge concerning LT4 dose requirements in patients with thyroid cancer according to different therapeutic approaches, taking into account a number of factors causing interference with LT4 efficacy. Specific mention is also made about the use of the novel LT4 formulations.

A comparative cross-sectional study on sleep quality in patients with a history of differentiated thyroid carcinoma and its correlation with quality of life

PURPOSE

To evaluate sleep quality in differentiated thyroid carcinoma (DTC) patients and correlate sleep disturbances with quality of life (QoL).

METHODS

119 DTC patients were enrolled (DTC group). The Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI) inventories were administered. The Thyroid-specific Patient-Reported Outcome (ThyPRO) questionnaire, the Billewicz scale (BS) and an ad-hoc visual analogic scale (VAS) were used to measure QoL and subjective therapy-related complaints. The same examinations were conducted in 53 subjects (control group) who had undergone surgery for benign thyroid pathology.

RESULTS

L-T4 dosages and TSH levels differed between the groups. BS and VAS scores were comparable. PSQI documented a similar percentage of poor sleepers in the DTC (74%) and control (62%) groups. ISI showed no difference in subjects without clinically significant insomnia: DTC (43%) and controls (48%). ThyPRO showed significantly worse scores in DTC than control subjects. In DTC patients, PSQI (P = 0.002) and ISI (P = 0.04) correlated significantly with age. In control subjects, TSH displayed a significant positive association with PSQI (P = 0.02) and ISI (P < 0.05). The ThyPRO general score correlated significantly with PSQI in DTC patients. In both groups, ISI correlated significantly with several ThyPRO scales and the ThyPRO general score. "Anxiety" and "emotional susceptibility" were the scales most significantly related with PSQI and ISI.

CONCLUSION

In disease-free DTC patients and subjects who undergo thyroid surgery for benign pathology, abnormal sleep components and insomnia are similar. The ThyPRO questionnaire closely reflects sleep disturbances in all subjects. Recognising and treating sleep disturbances might improve QoL.

Evaluation of Quality of Life in Patients with Differentiated Thyroid Cancer by Means of the Thyroid-Specific Patient-Reported Outcome Questionnaire: A 5-Year Longitudinal Study

BACKGROUND

Patients with malignancy suffer impairment of their quality of life (QoL). QoL has been evaluated in thyroid cancer patients. Since 2010, a new inventory, the thyroid-specific patient-reported outcome (ThyPRO) measure for benign thyroid disorders, has been available.

AIM

This study evaluated QoL longitudinally in patients with a history of differentiated thyroid cancer (DTC) by means of the ThyPRO questionnaire. Methods : From 2012 to 2016, QoL was evaluated yearly in 123 adult DTC patients by means of ThyPRO. The ThyPRO questionnaire consists of 13 scales on which higher scores represent greater impact on QoL in areas affected by thyroid pathology. Disease-specific morbidity due to possible inadequate L-T4 treatment was evaluated by means of the Billewicz scale (BS). The same examinations were conducted in 192 control subjects who had undergone surgery for benign thyroid pathology.

RESULTS

DTC and control subjects had similar scores on all but one scale; scores on the hyperthyroid symptoms scale were significantly higher in DTC patients than in controls. Over the 5 years, scores did not change significantly in the DTC group. Overall, QoL and BS scores showed a slight, but not significant, improvement during the study period in DTC patients. BMI impacted on several ThyPRO scales. No significant differences between genders were noted in DTC.

CONCLUSIONS

The ThyPRO questionnaire indicates that illness perception is similar after thyroidectomy for malign and benign pathology. Only a marginal improvement in QoL was noted in DTC subjects over the 5-year study period. In both groups, females showed a greater perception of illness than males.

Cross-sectional and prospective study on anti-Müllerian hormone changes in a cohort of pre-menopausal women with a history of differentiated thyroid cancer

Background

Anti-Müllerian hormone (AMH) decreases acutely after post-surgical radioactive iodine (RAI) ablation in females with differentiated thyroid cancer (DTC).

Aim

We performed a cross-sectional and prospective study on AMH levels in pre-menopausal females with a history of DTC.

Methods

Fifty-nine females after surgery and RAI (group 1) and 30 females after surgery alone (group 2) were studied. The control group consisted of 141 healthy women (group 3). The prospective study was performed in 43 and 14 females from groups 1 and 2, respectively.

Results

On first evaluation, AMH levels were similar in groups 1 and 2, but lower than in group 3. In all groups, AMH was negatively related with chronological age and FSH levels. When subjects were stratified according to age, AMH levels were not different between groups. When AMH was evaluated up to 2 years after the baseline evaluation, no changes emerged in either group of women with DTC. In the prospective study, the incidence of abnormal menstrual cycles and the onset of menopause were observed in similar percentages of women with a history of RAI-treated DTC and of those treated with surgery alone.

Conclusions

AMH can be considered a reliable index of ovarian reserve in women with DTC. Chronological age is the main factor influencing AMH levels in both DTC patients and controls. After age-related stratification, AMH levels are similar in women with DTC treated with RAI and those treated with surgery alone.

Levothyroxine Therapy in Thyrodectomized Patients

Administration of the optimal dose of levothyroxine (LT4) is crucial to restore euthyroidism after total thyroidectomy. An insufficient or excessive dosage may result in hypothyroidism or thyrotoxicosis, either one associated with a number of symptoms/complications. Most literature regarding the LT4 dosage deals with the treatment of primary hypothyroidism, whereas a limited number of studies handle the issue of thyroxin replacement after total thyroidectomy. A literature review was performed focusing on all papers dealing with this topic within the last 15 years. Papers that reported a scheme to calculate the proper LT4 dose were collected and compared to set up a review exploring limits and drawbacks of LT4 replacement therapy in the wide population of patients who had undergone thyroidectomy. Most of the methods for monitoring and adjusting thyroid hormone replacement after thyroidectomy for benign disease use LT4 at an empirical dose of approximately 1.6 μg/kg, with subsequent changes according to thyroid function test results and assessments of the patient's symptoms. Approximately 75% of patients require a dose adjustment, suggesting that factors other than body weight play a role in the determination of the proper LT4 dose. Hence, several schemes are reported in the literature for the proper initial dose of LT4. An inadequate level of thyroid hormone levels in these patients can be due to several factors. The most common ones that lead to the necessity of LT4 dose adjustments include lack of compliance, changes in LT4 formulation, dosage errors, increased serum levels of T4-binding globulin, body mass changes, and dietary habits. Moreover, concomitant ingestion of calcium supplements, ferrous sulfate, proton-pump inhibitors, bile acid sequestrants, and sucralfate might influence LT4 absorption and/or metabolism. Furthermore, some gastrointestinal conditions and their treatments can contribute to suboptimal LT4 performance by altering gastric acidity and thereby reducing its bioavailability, particularly in the solid form. Beyond the classic tablet form, new formulations of LT4, such as a soft gel capsule and an oral solution, recently became available. The liquid formulation is supposed to overcome the food and beverages interference with absorption of LT4 tablets.

Novel thyroxine formulations: a further step toward precision medicine

Levothyroxine (T4) is a critical-dose drug, because little variations in the blood concentration may cause treatment failure as well as iatrogenic thyrotoxicosis. Despite the dose response of this drug being more carefully titrated nowadays, several papers still report that a significant fraction of patients treated with levothyroxine demonstrate a TSH which is not on target. Moreover, some widespread gastrointestinal disorders as well as interfering drugs and foods may cause the "refractoriness" of a significant number of patients to an expected dose of thyroxine. The increasing awareness of the mechanisms interfering with the oral thyroid hormone bioavailability and the body of evidence regarding the complexity of treatment in certain classes of patients prompted pharmaceutical research to identify new hormonal formulations to optimize the performance of this drug. In this brief review, the progression of the scientific knowledge of novel T4 formulations use has been analyzed.

Oral L-thyroxine liquid versus tablet in patients submitted to total thyroidectomy for thyroid cancer (without malabsorption): A prospective study

Objective

No consistent data are present in literature about the effectiveness of Levothyroxine (L‐T4) liquid formulation in patients without malabsorption after thyroidectomy. The aim of this study is to compare the effectiveness of L‐T4 liquid formulation, with L‐T4 tablets, in thyroid cancer patients after thyroidectomy (without malabsorption or drug interference).

Methods

One hundred five patients were recruited; 52 patients were treated with liquid L‐T4 formulation, while 53 with L‐T4 tablets, at the same dosage (1.5 mcg/kg/day). Patients started to assume the drug the day after surgery, 30 min before breakfast. In both groups circulating levels of thyrotropic hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were dosed at week 6 (first control), and then at week 12 (second control).

Results

We obtained significantly lower TSH values in the liquid L‐T4 group patients, compared to the tablet L‐T4 group, at the first control (P < .05), and at the second control (P < .01), while FT4 and FT3 levels were not significantly different. Hypothyroid range (TSH > 3.6 mcU/mL) was significantly more prevalent in the patients treated with L‐T4 tablet.

Conclusions

A better control of TSH was observed in thyroidectomized patients (without malabsorption, gastric disorders, or drug interference) with liquid L‐T4 regimen.

Level of Evidence

2c–Outcomes Research

Evaluation of adequacy of levo-thyroxine dosage in patients with differentiated thyroid carcinoma: correlation between morning and afternoon TSH determination

PURPOSE

The aim of this study was to judge the reliability of evaluating thyroid-stimulating hormone (TSH) and free thyroxine (f-T4) in the morning and afternoon in differentiated thyroid carcinoma (DTC) patients.

METHODS

We evaluated 153 DTC patients, aged 61 ± 13 years, in active follow-up in our center after primary treatments and under stabilized levo-thyroxine (L-T4) posology. In each patient, morning and afternoon examinations were performed 1-3 months apart. Blood samples were collected at 08:00-09:00 h and 15:00-16:00 h. TSH and f-T4 were evaluated in both samples. Thyroglobulin (Tg), Tg-antibodies and neck ultrasonography were also evaluated.

RESULTS

According to clinical and laboratory examinations, 92% of patients were disease-free, 6% had biochemical disease, and 2% structural disease. L-T4 dosages (1.64 ± 0.38 µg/kg b.w.) proved the same on both occasions, despite slight changes in body weight or L-T4 posology in 15% of patients. Free-T4 values were significantly higher in the afternoon (21.5 ± 0.3 pmol/L) than in the morning (18.8 ± 0.4 pmol/L; P < 0.0001), whereas TSH values were statistically unchanged (morning 0.85 ± 0.25 mIU/L; afternoon 0.72 ± 0.20 mIU/L). There was a significant correlation (P < 0.0001) between the two TSH determinations in the same patients.

CONCLUSIONS

In DTC patients, follow-up examination consists of clinical and laboratory evaluations. The majority of patients have good disease control. Our study suggests that the adequacy of L-T4 therapy can be monitored equally well either in the morning or in the afternoon. Afternoon examinations can alleviate crowding in hospital ambulatories in the morning.

Liquid L-thyroxine versus tablet L-thyroxine in patients on L- thyroxine replacement or suppressive therapy: a meta-analysis

PURPOSE

To compare the effectiveness of liquid L-T4 (L-thyroxine) and tablet L-T4 in patients on L-T4 replacement or suppressive therapy.

METHODS

The Cochrane Library, PubMed, Embase, and Web of Science databases were searched to identify relevant articles. All prospective or randomized controlled studies (RCTs) comparing liquid L-T4 and tablet L-T4 in patients on L-T4 replacement or suppressive therapy were included in the analysis.

RESULTS

Overall, the initial search of the four databases identified 1278 published studies; of these, eight studies were ultimately included in the meta-analysis. TSH (thyroid stimulating hormone) levels were significantly suppressed in patients on liquid L-T4 compared with those on tablet L-T4, in patients on L-T4 suppressive therapy with L-T4 malabsorption (Mean Difference (MD) = -2.26, 95% Confidence Interval (CI): -3.59, -0.93; P = 0.0009)). However, liquid L-T4 and tablet L-T4 did not show a statistically significant difference in patients on L-T4 suppressive therapy without malabsorption (MD = 0.08, 95% CI: -0.31, 0.47; P = 0.69). TSH levels were significantly normalized in patients on liquid L-T4 compared with those on tablet L-T4, in Patients on L-T4 replacement therapy with L-T4 malabsorption (MD = -3.20, 95% CI: -5.08, -1.32; P = 0.0009). However, liquid L-T4 and tablet L-T4 did not show a statistically significant difference in patients on L-T4 replacement therapy without malabsorption (MD = 0.91, 95% CI: -0.03, 1.86; P = 0.06).

CONCLUSION

Liquid L-T4 is more efficient than tablet L-T4 in patients on L-T4 replacement or suppressive therapy with malabsorption. No significant differences were observed in patients without malabsorption. Further studies should be conducted to verify these findings.

Levothyroxine Therapy: Changes of TSH Levels by Switching Patients from Tablet to Liquid Formulation. A Systematic Review and Meta-Analysis

BACKGROUND

In the last years, levothyroxine (LT4) has been commercialized also in liquid formulation, which is less sensitive to the factors known to reduce the absorption of tablet LT4. To date, there is no robust information that liquid LT4 can improve pharmacologic thyroid homeostasis of patients with reduced efficacy of tablet LT4. This analysis aimed at achieving solid evidence that switching thyroxine treatment from tablet to liquid preparation improves patients' TSH levels.

METHODS

The search was performed in PubMed/MEDLINE and Scopus database based on the terms "thyroid," "levothyroxine," and "liquid," and updated until September 25, 2017. Studies were included only if they described patients with suboptimal TSH on tablet LT4, subsequently switched to liquid LT4.

RESULTS

The literature search retrieved 462 articles and six were finally included. The pooled mean difference of TSH value between tablet and liquid LT4 was 4.23 mIU/L (95% CI from 3.69 to 4.77). Mild heterogeneity was found (I₂ 60%). Overall mean difference of TSH was significant (p < 0.0001).

CONCLUSION

The present meta-analysis showed that patients with suboptimal TSH on tablet LT4 can have a significantly improved TSH by switching to liquid LT4 formulation at unchanged dose.

Detection of Polyethylene Glycol Thyrotropin (TSH) Precipitable Percentage (Macro-TSH) in Patients with a History of Thyroid Cancer

BACKGROUND

Owing to its large molecular size, polyethylene glycol (PEG)-precipitable thyrotropin (TSH) can accumulate in the circulation, elevating TSH levels. PEG-precipitable TSH can be used to detect macro-TSH (mTSH) in serum. Our aim was to evaluate the prevalence of mTSH in patients who had undergone thyroidectomy for thyroid cancer.

METHODS

Seventy-three thyroid cancer patients and 24 control subjects on levothyroxine (LT4) TSH-suppressive or replacement therapy were evaluated. Screening for mTSH was performed by adding PEG to serum in order to precipitate γ-globulin. A percentage of PEG-precipitable TSH ≥80% was considered suggestive of mTSH.

RESULTS

No correlation between free-T4 (fT4) and TSH levels was found. PEG-precipitable TSH was 39.3%±1.9% in thyroid cancer patients and 44.1%±3.9% in controls. Macro-TSH was deemed to be present in one thyroid cancer patient and in two control subjects. Only in the thyroid cancer group was PEG-precipitable TSH found to be negatively correlated with fT4 concentration. No correlation was found between PEG-precipitable TSH and other clinical conditions in any patients.

CONCLUSION

The presence of mTSH seems to be a rare phenomenon in thyroid cancer. In some patients with low PEG-precipitable TSH, a reduction in LT4 dosage could be suggested. LT4 dosage adjusted to body weight is the main factor in maintaining TSH in a semi-suppressed or normal range. Evaluation of mTSH could be necessary in patients in whom a balance is required between adequate TSH suppression and the avoidance of unnecessary exogenous hyperthyroxinemia.

Retrospective Study of Patients Switched from Tablet Formulations to a Gel Cap Formulation of Levothyroxine: Results of the CONTROL Switch Study

INTRODUCTION

Medication changes involving levothyroxine-either dose titrations or switching formulations-occur frequently in patients with erratic thyroid-stimulating hormone (TSH) levels and persistent hypothyroid symptoms. We investigated whether switching patients from levothyroxine tablets to a gel cap formulation of levothyroxine might reduce dose adjustments and improve tolerability and efficacy outcomes.

OBJECTIVES

Primary study objectives included quantifying the percentage of patients achieving TSH levels within a pre-specified range, median dose changes experienced, and the percentage of patients with improved hypothyroid symptom control after switching from levothyroxine tablets to levothyroxine gel caps.

METHODS

A retrospective medical chart review was conducted among 99 randomly selected hypothyroid patients who were switched from a tablet to a gel cap formulation of levothyroxine. Patients were required to have been on levothyroxine monotherapy for ≥1 year prior to the medication switch. Data was collected for 6 months pre-switch and up to 6 months post-switch.

RESULTS

Of the 99 patients studied, the majority (51.5%) experienced no documented change in TSH status after the switch (P < 0.0001). However, there was a decrease in the mean number of dose changes experienced (1.61 ± 0.96 vs. 0.73 ± 0.96; P < 0.0001). Improved hypothyroid symptom control was reported among 61.6% of patients (61 of 99; P < 0.0001).

CONCLUSION

The results of CONTROL Switch support a strategy of switching patients who may experience tolerability or efficacy problems with standard levothyroxine tablets to the levothyroxine gel cap formulation.

TSH Variability of Patients Affected by Differentiated Thyroid Cancer Treated with Levothyroxine Liquid Solution or Tablet Form

BACKGROUND

Recent guidelines from the American Thyroid Association (ATA) indicate that, in many patients affected by differentiated thyroid cancer (DTC), the serum TSH should be maintained between 0.1 and 0.5 mU/L. The purpose of this study was to evaluate the TSH variability of patients affected by DTC treated with liquid L-T4 formulation or in tablet form.

PATIENTS AND METHODS

Patients were eligible if (a) they were submitted to a total thyroidectomy and ¹³¹I remnant ablation for DTC in our institution and (b) they were classified low-risk patients according to ATA guidelines 2009. Patients were randomized (1 : 1) to receive treatment of hypothyroidism with liquid L-T4 or tablet form. The first check-up evaluation was made from 8 to 12 months after ¹³¹I remnant ablation. TSH values were established again after further 12 months.

RESULTS

A significant increase in TSH values (median) was observed in patients taking tablets [TSH (min-max): 0.28 (0.1-0.45) versus 0.34 (0.01-0.78) mIU/L, p = 0.041] as compared to those taking liquid formulation [TSH (min-max): 0.28 (0.1-0.47) versus 0.30 (0.1-0.55) mIU/L, p = 0.345].

CONCLUSIONS

The use of L-T4 liquid formulation, as compared to that of tablets, resulted in a significantly higher number of DTC patients maintaining TSH values in range for the ATA risk score, reducing TSH variability over the time.

Liquid and softgel levothyroxine use in clinical practice: state of the art

Levothyroxine is recognized as the treatment of choice for hypothyroidism. So far, the tablet levothyroxine has been the formulation almost exclusively used, even though an optimal daily dose of levothyroxine has been unsuccessfully sought and a consensus not achieved. Due to progressive use of a more individually tailored levothyroxine dose, increasing evidence has instead displayed that many gastrointestinal disorders, polypharmacy, and food interference may raise the daily levothyroxine requirement. In recent years, alternative levothyroxine formulations have become available and have rapidly gained attention because of their pharmacokinetic properties. This study aims to provide an overview regarding the use of softgel capsule and/or liquid levothyroxine solution while performing a review of published studies about such topic. A comprehensive computer literature search of the PubMed/MEDLINE, Scopus, and Google Scholar databases has been conducted to find published articles on this topic. The search algorithm was based on the combinations of the following terms: "oral solution" or "soft gel" or "liquid", and "levothyroxine". The computer search resulted in 75 articles; through a critical review of such titles and abstracts and a screening of their references lists, the review included 18 original articles relating to 800 patients treated with alternative formulations. Despite some limits, the results obtained using softgel and liquid levothyroxine were consistent with each other. In selected categories of levothyroxine-treated patients (pediatric, suffering from hypo-achlorhydria, polypharmacy, undergone bariatric surgery, fed through enteric tube) these new formulations have shown promising attributes in improving a treatment that needs to be individually tailored.

Oral L-thyroxine liquid versus tablet in patients with hypothyroidism without malabsorption: a prospective study

No consistent data are present in literature about the effectiveness of levothyroxine (L-T4) liquid formulation in patients without malabsorption. The aim of this study is to compare the effectiveness of L-T4 liquid formulation, with L-T4 tablets, in hypothyroid patients without malabsorption or drug interference. One hundred and fifty two patients were recruited. Patients were switched from the L-T4 therapy in tablets, to liquid L-T4 at the same dosage, 30 min before breakfast. Serum thyrotropic hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were re-evaluated after 1-3 months (first control) and 5-7 months (second control) from the switch. TSH values significantly declined with respect to the basal value after the switch to liquid L-T4 both at the first control (P < 0.05) and at the second control (P < 0.01); FT4 and FT3 levels were not significantly changed. We show that liquid L-T4 is more effective than L-T4 tablet in controlling TSH levels in hypothyroid patients without malabsorption, gastric disorders, or drug interference.