Vigersky Robert A, Filmore-Nassar Amy, Glass Allan R
Endocrinology Service, Walter Reed, Army Medical Center, Washington, DC 20307, USA.
J Clin Endocrinol Metab. 2006 Jan;91(1):225-7. doi: 10.1210/jc.2005-1210. Epub 2005 Oct 11.
Drug-drug interactions are common but often are discovered only long after initial drug release. Metformin has been available in the United States for 9 yr and elsewhere for many years, but as of yet there are no reports that the drug modifies thyroid hormone economy.
The objective of the study was to describe the clinical and biochemical findings of four patients with chronic hypothyroidism, previously euthyroid on fixed doses of L-T4 for several years, in whom the metformin was initiated.
This was a retrospective review.
The study was conducted at a tertiary care military hospital providing care to active-duty soldiers, sailors, and marines, retirees of the armed forces, and their eligible dependents.
Four patients with chronic hypothyroidism who were placed on metformin participated in the study. INTERVENTION, MAIN OUTCOME MEASURE: Serum TSH, free T4, and free T3 levels were measured during metformin treatment.
Initiation of treatment with metformin (three for diabetes mellitus and one for nonalcoholic steatohepatitis) caused suppression of TSH to subnormal levels without clinical symptoms of hyperthyroidism in any patients. There was no change in free T4 or free T3 in patient 1.
No other potential causes of TSH suppression, including medication changes or interference in the TSH assay, could be identified. The mechanism of the fall in serum TSH in these four patients is unclear at this time. Should these findings be confirmed in larger prospective studies, metformin's ability to suppress TSH without causing clinical or chemical hyperthyroidism might render this drug a useful adjunct to the treatment of patients with thyroid cancer.
药物相互作用很常见，但往往在药物首次上市后很长时间才被发现。二甲双胍在美国已上市9年，在其他地方也已上市多年，但尚未有该药物影响甲状腺激素代谢的报道。
本研究的目的是描述4例慢性甲状腺功能减退患者的临床和生化检查结果，这些患者此前多年一直服用固定剂量的左甲状腺素（L-T4）且甲状腺功能正常，之后开始服用二甲双胍。
这是一项回顾性研究。
该研究在一家三级军事医疗中心进行，为现役士兵、水手和海军陆战队队员、武装部队退休人员及其符合条件的家属提供医疗服务。
4例慢性甲状腺功能减退患者参与了本研究，他们开始服用二甲双胍。干预措施、主要观察指标：在二甲双胍治疗期间测量血清促甲状腺激素（TSH）、游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）水平。
开始使用二甲双胍治疗（3例用于糖尿病，1例用于非酒精性脂肪性肝炎）后，所有患者的TSH均降至正常水平以下，但均无甲状腺功能亢进的临床症状。患者1的FT4和FT3无变化。
未发现其他导致TSH降低的潜在原因，包括药物变化或TSH检测干扰。目前尚不清楚这4例患者血清TSH下降的机制。如果这些发现能在更大规模的前瞻性研究中得到证实，二甲双胍在不引起临床或生化甲状腺功能亢进的情况下抑制TSH的能力可能使其成为甲状腺癌患者治疗的有用辅助药物。
