Ross D S
Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston.
Mayo Clin Proc. 1988 Dec;63(12):1223-9. doi: 10.1016/s0025-6196(12)65409-3.
Many patients taking customary doses of levothyroxine have slightly elevated serum thyroxine (T4), apparently normal serum triiodothyronine, suppressed serum thyrotropin (thyroid-stimulating hormone; TSH) concentrations, and no clinical symptoms of hyperthyroidism. Recent reports suggest that these patients may have adverse effects from subclinical hyperthyroidism, including abnormally short systolic time intervals, elevations in liver enzymes, and reductions in bone density. Controversy exists about which thyroid function tests should be used to monitor patients taking levothyroxine. A review of currently available data suggests that replacement doses of levothyroxine given to hypothyroid patients should be adjusted so that serum TSH measured by the new sensitive assays is within the normal range. Patients requiring suppressive doses of levothyroxine to shrink goitrous thyroid tissue or to prevent growth of abnormal tissue should be given the minimal dose needed to accomplish the desired clinical or biochemical response.
许多服用常规剂量左甲状腺素的患者血清甲状腺素（T4）略有升高，血清三碘甲状腺原氨酸明显正常，血清促甲状腺素（甲状腺刺激激素；TSH）浓度受到抑制，且无甲状腺功能亢进的临床症状。最近的报告表明，这些患者可能因亚临床甲状腺功能亢进而产生不良反应，包括收缩期时间间隔异常缩短、肝酶升高和骨密度降低。关于应使用哪些甲状腺功能测试来监测服用左甲状腺素的患者存在争议。对现有数据的回顾表明，给予甲状腺功能减退患者的左甲状腺素替代剂量应进行调整，以便通过新的敏感检测方法测得的血清TSH在正常范围内。需要服用抑制剂量左甲状腺素来缩小甲状腺肿组织或防止异常组织生长的患者，应给予实现所需临床或生化反应所需的最小剂量。
