Comparison of blood methotrexate level according to the route of administration in non-surgical treatment of ectopic pregnancy / 대한산부인과학회지

ABSTRACT

OBJECTIVE: This study was performed to compare the pharmacokinetics of methotrexate (MTX) in unruptured ectopic pregnancy according to the injection route. METHODS: Between May 2005 and August 2009, thirty-five patients of unruptured ectopic pregnancy in Chungbuk National University Hospital were treated medically either by intramuscular (IM) or intraamniotic (IA) injection of MTX according to the presence of fetal heart beat. Serum concentration of MTX was measured by fluorescent immunoassay using the blood samples withdrawn serially after its injection. RESULTS: The peak plasma MTX level was achieved at the 30-minute after injection sample in both groups. The mean peak plasma level of MTX in IM group was significantly higher than that of IA in 60-minute (2.296+/-0.64 umol/L vs 1.535+/-0.31 umol/L; p<0.006), 90-minute (1.9+/-0.51 umol/L vs 1.225+/-0.21 umol/L; p<0.002), and 240-minute (1.443+/-0.33 umol/L vs 1.077+/-0.18 umol/L; p<0.011) samples. The mean pretreatment plasma beta-hCG level was significantly higher in IA group, both tubal pregnancy (48,405+/-37,811.7 IU/L vs 18,452.05+/-19,205.34 IU/L; p<0.007) and cervical pregnancy (94,574.2+/-45,037.1 IU/L vs 42,446+/-34,778.12 IU/L; p<0.037), than those of IM group. But neither plasma MTX level nor pretreatment beta-hCG level were related to the treatment outcome. CONCLUSION: The plasma level of MTX increased rapidly in both IM and IA groups; the peak level reached at 30 minutes, and decreased to less than 1 umol/L after 240 minutes. Moreover, it was higher in IM group than IA group. Nevertheless, IA injection may be useful in patients who had high beta-hCG level or fetal heart beat, which are not usually indicated to medical treatment.