Amitriptyline is the most useful in a class of drugs known as tri- cyclic antidepressants (TCAs). These drugs can be lethal if taken in a certain way.
The TCAs date back to the early 1960s where they established themselves as useful antidepressants. However, their narrow ther- apeutic margin (the dose needed for therapy as an antidepressant and that which is toxic is close) meant that there were dangers in prescribing these drugs, especially to depressed people, from either accidental or intentional overdose.
Their implication in a large number of deaths from overdose meant that other classes of safer antidepressants such as the sera- tonin re-uptake inhibitors (SSRI) like fluoxetine (Prozac) found favour and largely displaced the TCAs.
Since this time the TCAs have undergone something of a resur- gence for the treatment of intractable neuropathic pain (such as trigeminal neuralgia) and migraine.