Incidence of tricyclic antidepressant-like complications after cyclobenzaprine overdose

Abstract

Background: The cyclobenzaprine structure is similar to amitriptyline; however, tricyclic antidepressant (TCA)-like wide complex dysrhythmia has not been reported. Our objective was to determine the incidence of TCA-like effects in cyclobenzaprine overdoses as reported to 6 poison centers for 2 years. We compared the incidence of these effects to amitriptyline overdoses collected during the same period. Methods: We performed a retrospective review of 2 years of cases as reported to the Texas Poison Center Network. We identified sole ingestions of cyclobenzaprine and of amitriptyline. Cases had a recorded clinical outcome and clinical effect. A trained reviewer used a standard data collection sheet within a secured electronic database. One investigator audited a random sample of charts. Results: We identified 3974 cases of cyclobenzaprine calls. Of these, we collected 209 cases of acute overdoses without coingestions. There were no deaths. No cases of cyclobenzaprine ingestions were reported to have died or have a wide QRS or ventricular dysrhythmia. Seizures were reported in 2 cases; however, both were unrelated to cyclobenzaprine. Hypotension was reported in 1.4% (3/209) of cases, and a vasopressor was used in one case (0.5%). Patients with an amitriptyline overdose were more likely to have seizure, coma, tachycardia, a wide QRS or ventricular dysrhythmia, and have received sodium bicarbonate or be intubated. Conclusions: Cyclobenzaprine overdoses were not reported to cause widened QRS, ventricular dysrhythmias, or seizures, and hypotension was rarely reported. Tricyclic antidepressant-related effects occurred more often in our comparison group of amitriptyline overdoses.

The Role of Sodium Bicarbonate in the Management of Some Toxic Ingestions

“…Other medications such as antiarrhythmics [ 36 – 38 ], non-TCA antidepressants [ 39 , 40 ], antiepileptic medications [ 41 – 43 ], cyclobenzaprine [ 43 , 44 ], propranolol [ 45 ], cocaine [ 46 ], and certain antihistamines [ 47 ] may produce similar ECG and clinical manifestations with favorable response to similarly administered IV sodium bicarbonate. Amantadine overdose may result in a similar cardiac sodium channel toxicity though IV sodium bicarbonate was not specifically used in the reported cases because of concomitant hypokalemia [ 48 ].…”

Use of an Intravascular Heat Exchange Catheter and Intravenous Lipid Emulsion for Hypothermic Cardiac Arrest After Cyclobenzaprine Overdose

“…Previous case reports have documented the use of sodium bicarbonate therapy in cyclobenzaprine toxicity (Bebarta et al, 2011). This may theoretically benefit patients, especially those with widened QRS complexes due to structural similarity to tricyclic antidepressants.…”

“…Clinical manifestations following an acute toxic ingestion may be consistent with anticholinergic toxicity (Bebarta et al, 2011). While it has been suggested that QRS complex widening, ventricular dysrhythmias, and seizures may occur due to its structural similarity to tricyclic antidepressants, several previous studies have demonstrated that the actual incidence of these events in the setting of cyclobenzaprine toxicity is relatively rare (Spiller et al, 1995;Bebarta et al, 2011).…”

Cardiovascular Toxicity as a Result of Psychotropic Drugs

“…48 A meta-analysis from 15 randomized controlled trials (RCTs) with a total of 3779 patients found a greater incidence of tachycardia (9%) in the paliperidone group with an attributable risk of 4. 55 Amitriptyline intoxication was also associated with tachycardia, 56,57 and more than 60% of these individuals experienced increased heart rate. 52 It is contraindicated for treatment of psychotic symptoms in older adults with dementia due to its strong association with stroke during treatments.…”