The drugs have several characteristics that make them useful as reliable and lethal drugs. In particular they exhibit cardiotoxic and central nervous system (CNS) effects. CNS symptoms in- clude sedation and coma, but it is the cardiotoxic effects that reduce cardiac output, lower blood pressure and disrupt car- diac rhythm that bring about death.
The toxic effects are accentuated if the drug is rapidly absorbed from the gut and this occurs in the alkaline environment of the small intestine. Preparation as a drink facilitates this, as does the use of an anti-emetic like metoclopramide (Maxolon) which speeds gastric emptying.
Fig 12.1 The tricyclic antidepressant amitriptyline