Pharmacology in Emergency Medicine| Volume 48, ISSUE 4, P458-460, April 2015

Download started.


Profound Symptomatic Bradycardia Requiring Transvenous Pacing After a Single Dose of Tizanidine

Published:November 18, 2014DOI:



      We report a case of profound symptomatic bradycardia after a single dose of tizanidine.

      Case Report

      A 93-year-old female became altered and was found to have hypotension and profound symptomatic bradycardia 30 min post ingestion of a single 4-mg dose of tizanidine at her physician's office. Emergency Medical Services was called to scene and patient was transported to our tertiary medical center. In the emergency department, the patient required intubation, vasopressor support, and transcutaneous pacing. An electrocardiogram revealed atrial fibrillation with slow ventricular response with a heart rate of 19 beats/min. The patient was transferred to the intensive care unit and subsequently taken for cardiac catheterization, where a transvenous pacer was placed. During the next few days, her vital signs and mental status improved, allowing for successful extubation. Before discharge, the patient received a single-chamber pacemaker.


      Profound symptomatic bradycardia from a single dose of tizanidine has not been reported. A review of the patient's medications did not reveal a significant cytochrome P450 drug interaction to result in an adverse effect as previously reported in the literature.


      Tizanidine should be used cautiously in elderly population and drug interactions screening should be performed.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Emergency Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


      1. Tizanidine monograph. Clinical pharmacology. Gold Standard, Inc. Tampa, FL. Available at: Accessed June 26, 2013.

        • Kao C.
        • Chang J.
        • Chen J.
        • et al.
        Hypotension due to interaction between lisinopril and tizanidine.
        Ann Pharmacother. 2004; 38: 1840-1843
        • Publow S.W.
        • Branam D.L.
        Hypotension and bradycardia associated with concomitant tizanidine and lisinopril therapy.
        Am J Health Syst Pharm. 2010; 67: 1606-1610
        • Johnson T.R.
        • Tobias J.D.
        Hypotension following the initiation of tizanidine in a patient treated with an angiotensive converting enzyme inhibitor for chronic hypertension.
        J Child Neurol. 2000; 15: 818-819
      2. Drug Interactions. Micromedex 2.0. Truven Health Analytics, Inc. Greenwood Village, CO. Available at: Accessed June 26, 2013.

      3. Drug Interaction Report. Clinical pharmacology. Gold Standard, Inc. Tampa, FL. Available at: Accessed June 26, 2013.

      4. Lexi-Interact Online. Lexi-Comp. Wolters Kluwer Health, Inc. Hudson, OH. Available at: Accessed June 26, 2013.

        • Naranjo C.A.
        • Busto U.
        • Sellers E.M.
        • et al.
        A method for estimating the probability of adverse drug reactions.
        Clin Pharmacol Ther. 1981; 30: 239-245