 Naturally, in overdose, they can be cardiotoxic, prolonging heart rhythms and increasing myocardial irritability.New research has also revealed compelling evidence of a link between long-term use of anticholinergic medications like TCAs and dementia.Although many studies have investigated this link, this was the first study to use a long-term approach (over seven years) to find that dementias associated with anticholinergics may not be reversible even years after drug use stops.