Hospital Medicine. 2nd edition. Wachter RM; Goldman L; Hollander H; eds., Philadelphia, PA: Lippincott Williams & Wilkins, 2005 Apr; :1229-1242
There are many different initial manifestations of an acute drug overdose. These may include an altered level of consciousness, seizures, hypotension, cardiac arrhythmias, metabolic acidosis, or gastrointestinal symptoms. Important variables in the history include the specific drug or drugs taken, the amount taken, the time between the overdose and presentation, and any underlying medical illnesses Certain drugs (e.g., carbamazepine, salicylates, tricyclic antidepressants, sustained-release or enteric-coated preparations) may be absorbed slowly or erratically, which can delay the onset of toxicity. Some drugs (e.g., digoxin, lithium, salicylates, theophylline, metformin, verapamil) can cause toxicity after chronic, repeated overmedicate or In the presence of impaired drug elimination because of kidney or liver dysfunction.