Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ QT interval prolongation QRS prolongation (> 100 ms) is a sign of toxicity Rightward deviation of terminal 40 ms of the QRS is the most sensitive marker of toxicity (rightward terminal R wave in aVR) Ventricular arrhythmias +++ GENERAL CONSIDERATIONS ++ Properties are similar to those of class I antiarrhythmic agents Orthostatic hypotension secondary to alpha1-adrenergic receptor blockade may cause frequent falls, particularly in the elderly Ventricular proarrhythmia may occur in patients with serious structural heart disease Tricyclic antidepressant overdose carries a mortality rate of 2–3% secondary to cardiac complications – Generally considered second-line therapy for depression due to their cardiac and anticholinergic effects +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Dizziness, syncope Dry mouth Urinary hesitancy Muscle rigidity Incoordination Drowsiness Blurred vision +++ PHYSICAL EXAM FINDINGS ++ Orthostatic hypotension Irregular pulse Low blood pressure +++ DIFFERENTIAL DIAGNOSIS ++ Overdose of anticholinergic agents Brugada syndrome +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ Drug screen +++ ELECTROCARDIOGRAPHY ++ QT, ORS prolongation Terminal R wave in aVR Ventricular arrhythmias +++ TREATMENT +++ CARDIOLOGY REFERRAL ++ Ventricular arrhythmias Syncope Suspected tricyclic toxicity +++ HOSPITALIZATION CRITERIA ++ Syncope Serious ventricular arrhythmias Suspected overdose +++ MEDICATIONS ++ Aggressive supportive measures, such as gastric lavage, airway maintenance, and activated charcoal Alkalinization with IV bicarbonate for cardiac arrest, hypotension, arrhythmias, acidosis, and QRS prolongation +++ MONITORING ++ ECG monitoring in hospital +++ DIET AND ACTIVITY ++ Restricted activities until adverse effects are gone +++ ONGOING MANAGEMENT +++ HOSPITAL DISCHARGE CRITERIA ++ Resolution of drug effects +++ COMPLICATIONS ++ Sudden death +++ PROGNOSIS ++ Excellent with early recognition and appropriate treatment +++ PREVENTION ++ Patient education about drugs +++ RESOURCES +++ PRACTICE GUIDELINES ++ Tricyclic antidepressant overdose almost always requires hospitalization +++ REFERENCE + +Pruckner N, Holthoff-Detto V. Antidepressant pharmacotherapy in old-age depression: a review and clinical approach. Eur J Clin Pharmacol. 2017;73(6):661–667. [PubMed: 28280892] Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.