Abstracts

After we had noticed increased serum creatinine in single patients treated with lamotrigine (LTG) we decided to investigate the frequency and extent of this phenomenon in a greater number of patients. In a retrospective analysis of the data base of our laboratory we selected those patients in whom LTG was started or stopped in the year 2002. The relationship between LTG treatment and creatinine serum levels was investigated. We identified 80 patients (mean age 35.8 y, 41 males) with at least one serum level of creatinine before or after treatment with LTG and one to fourteen creatinine values obtained during this treatment. In 76 patients LTG was started and in 4 patients it was discontinued. There was a correlation between LTG and creatinine serum concentrations (r = 0.334), which was statistically significant (p [lt] 0.001, n = 265). In 48 patients with LTG [gt] 10 [mu]mol/l we compared the creatinine values corresponding to the maximum LTG levels with those obtained before or after treatment. This revealed an average increase of creatinine of 9.2 [mu]mol/l due to treatment with LTG, which was statistically significant (p[lt] 0.001, t-test). In detail, in 40 patients there was an increase ranging between 1.3 and 43 [mu]mol/l, whereas in the remainder creatinine decreased by 2.6 to 30.2 [mu]mol/l. However, pathological creatinine values ([gt] 100 [mu]mol/l) were found in only 4 patients, two of them had already patholgical values before LTG treatment. Even in these patients there were no signs or symptoms of any clinically relevant impairment of renal function due to LTG. LTG leads to increased creatinine serum levels, what has not been reported up to now. The mechanism of this effect remains to be elucidated. A clinical relevance of this finding seems rather unlikely, but cannot be ruled out in individual patients.