the lower levels of serum and rbc cholinesterase in acute opioid poisoning

Background: cholinesterase is an enzyme that plays a critical role in regulating neural transmission. many factors may decrease the cholinesterase levels in serum and red blood cells (rbcs). it is suggested that the use of opium may effectively change the levels of cholinesterase in serum and rbcs. this study aimed to evaluate the serum and rbc levels of cholinesterase in patients who were acutely poisoned with opium. methods: this cross-sectional study was conducted in 65 patients suffering from acute opium poisoning. the serum levels of cholinesterase were measured using an automated analyzer. the levels were also measured in rbcs, using a colorimetric method. simultaneously, 65 patients served as the positive controls from among those poisoned with organophosphates. results: the serum cholinesterase levels were lower than the normal range in 16.9% of patients poisoned with opium and in 76.9% of those poisoned with organophosphate agents (p<0.001). similarly, the levels of rbc cholinesterase were lower than the normal range as found in 64.6% and 15.4% of patients poisoned acutely with opium (group 1) and organophosphate (group 2), respectively (p<0.001). conclusion: acute opium poisoning effectively reduced both the levels and activities of cholinesterase in the patients’ serum and rbcs significantly different from those noted in patients suffering from organophosphate toxicity.