Management of tricyclic antidepressant overdose Essay

Management of tricyclic antidepressant overdose - Essay Example The major use of the drugs belonging to this class has been of course as an antidepressant, but they have also found to be effective in controlling enuresis and attention deficit disorder in children and incontinence in the elderly. Other miscellaneous indications for use are Migraine, chronic pain, neuralgias, hiccups and irritable bowel syndrome. However the Therapeutic Index of these drugs has a narrow margin of safety i.e. the dose level between therapeutic and toxic level is very less. This accounts for several cases of adverse effects and acute toxicity with these compounds. The toxicity is due to the same manner and mechanism of action in which the drug exerts its therapeutic action. Although poorly understood, the TCAs are hypothesized to exert their therapeutic action by preventing the reuptake of norepinephrine and serotonin by the presynaptic neuron. This results in an increased supply of these neurotransmitters in the synapse, which continues to stimulate the effector cells and organs. It is this constant stimulation that is believed to be responsible for the clinical improvement in depression (Baldessarini, 1989). According to Richelson (1982) TCAs are also competitive antagonists of histamine H1 andH2 receptors. They also block muscarinic acetylcholine and alpha-one adrenergic receptors. The toxicity symptoms and presentations are manifested as central nervous system toxicity in the form of myoclonic seizures, cardiovascular complications like life threatening arrhythmias, asystole, ventricular tachycardia and ventricular fibrillation. The patient is usually presented with symptoms of orthostatic hypotension which is quite common with TCA use and is independent of the age factor and in some cases is followed by cardiac arrest. Treatment is aimed at reversing the effects of the TCAs by specific antagonists, promoting elimination of the drug and its metabolites from the body and reestablishing