Prospective Study Of The Effect Of Methimazole And Propylthiouracil On Peripheral Blood Leucocytes

Objective:The primary objective of this paper was to observe the effect of Antithyroid drug (ATD) of Methimazole(MMI) and Propylthiouracil(PTU) on peripheral leucocytes during the period of therapy of hyperthyroidism.Methods:All the patients with hyperthyroidism were recruited from out-patient department and in-patient Department of Endocrine Department in Guangxi Medical University, the First Affiliated Hospital during the period of december2009to december2011. A total of189patients were included and then randomly divided into two groups:MMI treatment group(MMI group, n=97) and PTU treatment group(PTU group, n=92). ATD was administrated orally by three stages of initial, decrement and maintenance treatment. An individual out of the patients enrolled was followed up at least for six months. At the initial stage of treatment, the daily dose of ATD was30mg for MMI, or300mg for PTU. Periphery blood routine examination was taken every one to two weeks in the first three months of medication to review the blood cell count, whereafter repeated the same work every four to six weeks.Thyroid function and liver function were tested every four to six weeks during the following up period.Results:(1) After ATD administration, there were12cases (12.3%) to be found suffering from leucopenia in MMI group, significantly higher (P<0.05) than that in PTU group (4cases,4.3%).2cases (2.1%)with erythropenia and1case (1.0%) with thrombocytopenia could be seen in MMI group and the same was none in PTU group. Only one case appeared to be agranulocytosis in MMI group. There was no pancytopenia observed in all the patients involved.Out of all the patients with leucopenia,56%(9/16) shown neutropenia,6%(1/16) shown total white blood cell decrease and38%(6/16) shown both total white blood cell decrease and neutropenia.(2) Majority of patients with hypocytomsis (68.4%,13/19) shown up during the period of initial treatment.(3) The time when patients showing leucopenia after treatment was28(41)days [M(IQR)] towards MMI group and21(119)days [M(IQR)] towards PTU group and there was no significantly different between both groups (P>0.05).(4) The difference of parameters of thyroid function were no statistical significance in both group patients (p>0.05)Conclusions:MMI was more likely to cause peripheral blood leucopenia than PTU did in the treatment of hyperthyroidism. Leucopenia resulting of ATD usually could be seen in the period of initial treatment, especially in the first three months after administration of ATD. Majority of the patients only shown neutropenia while total white blood cells count to be remained in the normal range.