The Prospective Studies Of The Effect Of Methimazole And Propylthiouracil On The Liver Function

【Objective】To make an assessment of the effect of methimazole andpropylthiouracil on liver function during the period of treatment ofhyperthyroidism.【Background】 Antithyroid drugs(ATD), which have been used as thetreatments of hyperthyroidism especially towards Graves’ disease for more thanhalf a century, are the important therapeutics to hyperthyroidism and thefoundational therapy of131I and surgery as well. Methimazole (MMI) andpropylthiouracil(PTU) are two of the most commonly used antithyroid drugs atpresent. The adverse reactions of MMI and PTU include rash, joint pain,granulocytopenia, liver injury and so forth. Liver injury is not rare. Although thedegree of liver damage is fairly low in most cases, sometimes it may causeserious consequence and even death that we should take close attention to.【Methods】The objects of this study are189cases with hyperthyroidismwho came from The1stHospital of Guangxi Medical University from december2009to december2011. The patients are randomly divided into MMIgroup(n=97) and PTU group(n=92). Towards initial dose, patients wasadministered orally for MMI (30mg/d) or PTU (300mg/d) respectively.According to patients’ condition the initial dose will be then reduced graduallyto a suitable one of maintenane therapy(MMI5～10mg/d, PTU50～100mg/d).Parameters of thyroid function(T3,T4,FT3,FT4,TSH) and liver function(TBil, ALT,AST, ALP) were tested every four to six weeks after administration of ATD.An individual out of the patients enrolled was followed up for more than three months. Liver injury resulting of ATD was defined as at least one of theparameters of liver function above reached or exceeded twice normal upperlimit range(>=2N).【Results】Compared with MMI group(7cases), the incidence of liver injury inPTU group(17cases) was significantly higher (18.5%vs7.2%，p<0.05).Thetime of liver injury associated with MMI was slightly earlier than that withTPU[（20±8.5）days vs（41±26.4）days, p<0.05]. Majority of patients with liverinjury by both MMI(57.1%,4/7) and PTU(82.4%,14/17) was characterized bythe rise of ALT and the difference between the two groups was marked (p<0.05).Before treatment, there were34cases whose liver function indicators werebetween1N~2N in MMI group, accounting for35.1%, while there were31cases in PTU group, accounting for29.3%. After treatment, there was evidenceof liver injury to be seen coming from those patients above:4(11.8%) cases inMMI group and6(19.4%) cases in PTU group that liver function indicatorsexceed2N.【Conclusions】1. PTU was more likely to lead to liver injury comparedwith_MMI_, but the liver injury caused by MMI occurred earlier in time thanthat by PTU;2. PTU and MMI often lead to mild liver injury, which is characterized by theelevation of ALT;3. There was about one third of patients with hyperthyroidism to have slightlyliver injuries before treatment, but it would be unlikely to increase the risk offurther liver injury by the administration of ATD. 4. During the process of treatment of hyperthyroidism by ATD, the liver functionshould be tested periodically, especially in the first three months;5. Clinically, patients should be told in time that if nausea, inertia and jaundiceoccurred after taking orally the drugs and see the doctor immediately. Oncesevere liver injury to be found, physician should stopped drugs concerned andprotectant liver therapy should be given. In this paper, we suggest to useisotope iodine in the subsequent treatment of hyperthyroidism.