레보티록신 (갑상선 호르몬) 제제 사이의 변경

비록 의사와 환자가 합성 레보티록신 제제 간의 변경에 관한 우려를 할 수 있지만, 변경하는 것은 일반적으로 임상적 문제가 되지 않습니다.

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2780쌍에서 제네릭 레보티록신 제제 사이의 변경을 한 것과 하지 않은 그룹에서 TSH 수치의 변화를 평가는 비교 효과 연구에서 정상 범위에 있는 TSH 수치를 나타내는 사람의 비율은 유사했습니다 (각 82.7%, 84.5%). 한 제조사에서 다른 제조사로 변경한 경우 환자가 우려하거나, 혈청 TSH를 좁은 범위 내에서 유지하는 것이 중요한 경우(예: 갑상선암 치료), 좁은 범위 내에서 혈청 TSH를 유지하는 것이 중됴한 경우 혈청 TSH가 여전히 치료 범위에 있다는 것을 확인하기 위해 제제 변경 6주 이후에 혈청 TSH를 측정합니다.

 

Abstract

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Importance Switching among generic levothyroxine sodium products made by different manufacturers typically occurs at the pharmacy and may affect serum thyrotropin (TSH) levels.

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Objective To compare TSH levels between patients who continued taking the same sourced generic levothyroxine product and those who switched.

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Design, Setting, and Participants This comparative effectiveness research study with 1:1 propensity matching used data from OptumLabs Data Warehouse, a national administrative claims database linked to laboratory test results. Adults aged 18 years or older were included if they filled a generic levothyroxine prescription between January 1, 2008, and June 30, 2019, and had a stable drug dose, the same drug manufacturer, and a normal TSH level (0.3-4.4 mIU/L) for at least 3 months before either continuing to take the same product or switching among generic levothyroxine products (index date). Patients were excluded if they were pregnant, had diagnosed hypopituitarism or hyperthyroidism, or had a medical condition or used medications that could affect thyrotropin levels. They were also excluded if they filled a prescription for other forms of thyroid replacement therapy between 6 months before the index date and when the first TSH level was obtained 6 weeks to 12 months after the index date. Data were analyzed from December 1, 2019, to November 24, 2021.

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Main Outcomes and Measures Proportion of individuals with a normal (0.3-4.4 mIU/L) or markedly abnormal (<0.1 or >10.0 mIU/L) TSH level using the first available laboratory result 6 weeks to 12 months after the index date. A propensity score model was developed to minimize confounding using logistic regression with the binary outcome of continuing the same sourced levothyroxine product vs switching generic levothyroxine. Covariates were demographics, comorbidities, and baseline TSH level. The balance among the treatment groups was evaluated by comparing standardized mean differences of baseline covariates between the groups.

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Results A total of 15 829 patients filled generic levothyroxine (mean [SD] age, 58.9 [14.6] years; 73.4% [11 624] were women; 4.5% [705] were Asian, 10.2% [1617] were Black, 11.4% [1801] were Hispanic, and 71.4% [11 295] were White individuals); of these patients, 56.3% [8905] received a daily levothyroxine dose of 50 μg or less. A total of 13 049 patients (82.4%) continued taking the same sourced preparation, and 2780 (17.6%) switched among generic levothyroxine preparations. Among 2780 propensity-matched patient pairs, the proportion of patients with a normal TSH level after the index date was 82.7% (2298) among nonswitchers and 84.5% (2348) among switchers (risk difference, −0.018; 95% CI, −0.038 to 0.002; P = .07). The proportion of patients with a markedly abnormal TSH level after the index date was 3.1% (87) among nonswitchers and 2.5% (69) among switchers (risk difference, 0.007; 95% CI, −0.002 to 0.015; P = .14). The mean (SD) TSH levels after the index date were 2.7 (2.3) mIU/L among nonswitchers and 2.7 (3.3) mIU/L among switchers (P = .94).

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Conclusions and Relevance Results of this comparative effectiveness research study suggest that switching among different generic levothyroxine products was not associated with clinically significant changes in TSH level. These findings conflict with the current guideline recommendation that warns clinicians about potential changes in TSH level associated with switching among levothyroxine products sourced from different manufacturers.

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Ref. JAMA Intern Med. 2022;182(4):418-425.

UpToDate 2022.06.09