%0 Journal Article
%T Two cases of high serum clozapine concentrations occurring during inflammation in Chinese patients
%A Can-Jun Ruan
%A Chuan-Yue Wang
%A Fu-Chun Zhou
%A Hong-Yan Zhuang
%A Jose de Leon
%A Wei Guo
%A Wen-Biao Li
%A Xiao-Ling Zhang
%A Ya-Qiong Li
%A Yi-Lang Tang
%J The International Journal of Psychiatry in Medicine
%@ 1541-3527
%D 2018
%R 10.1177/0091217417749799
%X Serious infections or inflammations have been associated with serum clozapine concentration increases and sometimes with clozapine toxicity. These two cases describe Chinese patients (Case 1: a 57-year-old female nonsmoker with severe dermatitis and Case 2: a 47-year-old male nonsmoker with influenza and secondary infection). In both cases, the Drug Interaction Probability Scale established the presence of a probable drug¨Cdrug interaction. In both cases, the clozapine and the total clozapine concentration-to-dose ratios followed a temporal pattern (normal¨Chigh¨Cnormal), consistent with an inhibition of clozapine metabolism during peak inflammation. In the first case, the total clozapine concentration-to-dose ratio (8 with no/low inflammation: median of 3.10 and 2 at peak inflammation: median of 3.90) provided a significant difference (P£¿=£¿0.044). In the second patient, because of the smaller sample size and reduced statistical power (4 with no infection: a median of 1.59 and 2 at peak infection: 3.46), the increase did not reach significance (P£¿=£¿0.13). In the first case, the median baseline clozapine concentration-to-dose ratio increased by a factor of 1.45 from 2.00 to a peak of 2.89. To compensate for the inhibition of clozapine metabolism, the dose correction factor was 0.69 (1/1.45) or a decrease in dose of approximately one-third. In the second case, the median baseline clozapine concentration-to-dose ratio increased by a factor of 2.56 from 1.15 to a peak of 2.94. This provided a dose correction factor of 0.40 (1/2.56) or approximately half the dose, similar to published cases in Caucasians with serious respiratory infections
%K clozapine/blood
%K clozapine/pharmacokinetics
%K dermatitis
%K drug interaction
%K infection
%K influenza
%U https://journals.sagepub.com/doi/full/10.1177/0091217417749799