Abstract: | Cimetidine inhibited cholinesterases from human blood serum, erythrocytes, brain and gastric mucosa in a dose-dependent manner. The median inhibitory concentrations ranged between 7.0 x 10(-4) mol/l and 2.1 x 10(-3) mol/l. The inhibition was of competitive type, the inhibitory constant of acetylcholinesterases in erythrocytes were found to be 8.5 x 10(-5) mol/l and of pseudocholinesterases in serum 8.5 x 10(-4) mol/l. A significance of our findings may be the explanation of side effects seen in cimetidine overdosage. |