Although there have been descriptive, uncontrolled clinical reports of removal of
tablet debris by gastric lavage, there have been no clinical studies that have demonstrated that this has any impact on outcome in patients with
tricyclic antidepressant (TCA)
poisoning. There is also the possibility that lavage may increase
drug absorption by pushing
tablets into the small intestine. Furthermore, gastric lavage in patients with TCA
poisoning may induce
hypoxia and a
tachycardia potentially increasing the risk of severe complications such as arrhythmias and convulsions. In view of the paucity of evidence that gastric lavage removes a significant amount of
drug and the risk of complications associated with the procedure, the routine use of gastric lavage in the management of patients with TCA
poisoning is not appropriate. Volunteer studies have shown generally that
activated charcoal is more likely to reduce
drug absorption if it is administered within 1 hour of
drug ingestion. In the one volunteer study that looked at later administration of
activated charcoal, there was a 37% decrease in plasma concentration associated with administration of
activated charcoal at 2 hours post-ingestion. There have been no clinical studies that enable an estimate of the effect of
activated charcoal administration on outcome in the management of patients with TCA
poisoning. Volunteer studies have shown that multiple-dose
activated charcoal increases the elimination of therapeutic doses of
amitriptyline and
nortriptyline, but not of
doxepin or
imipramine; however, these studies cannot be directly extrapolated to the management of patients with TCA
poisoning. There have been no well designed controlled studies that have assessed the impact of multiple-dose
activated charcoal in the management of patients with TCA
poisoning. Because of the large volume of distribution of TCAs, it would not be expected that their elimination would be significantly increased by multiple-dose
activated charcoal.Haemoperfusion, haemodialysis and the combination of these procedures do not result in significant removal of TCAs and are not recommended in the management of patients with TCA
poisoning.