title: Hypotension and bradycardia associated with concomitant tizanidine and lisinopril therapy.
abstract: OBJECTIVE
  A case of severe bradycardia and hypotension associated with concomitant tizanidine and lisinopril therapy is reported.
  
  
  CONCLUSIONS
  An 85-year-old man with a chief complaint of profound weakness was admitted to the hospital with a blood pressure reading of 60/32 mm Hg and a heart rate of 37 beats/min. His medical history included type 2 diabetes mellitus, congestive heart failure, gastroesophageal reflux disease, chronic obstructive pulmonary disease, osteoarthritis, restless leg syndrome, benign prostatic hyperplasia, generalized anxiety disorder with depression, and severe chronic back pain for which he was receiving treatment at a pain clinic. Two days before hospital admission, he had been seen at the pain clinic and started on ti-zanidine. Additional medications included acetaminophen, chlorpromazine, citalopram, finasteride, lidocaine patch, lisinopril, metformin, pramipexole, omeprazole, simvastatin, theophylline, diclofenac topical gel, hydrocodone-acetaminophen, and ondansetron. After taking three doses of the newly prescribed tizanidine, he developed severe hypotension and bradycardia. Notable laboratory test values included a serum creatinine concentration of 1.90 mg/dL, a blood urea nitrogen concentration of 21 mg/dL, a serum potassium concentration of 5.5 meq/L, and a serum sodium concentration of 128 meq/L. Upon admission, tizanidine, lisinopril, theophylline, omeprazole, and simvastatin were withheld, and i.v. fluids were administered. The patient's vital signs began to gradually improve. Within 24 hours, the patient's blood pressure and heart rate had improved, as had the previously abnormal laboratory test values. Tizanidine was discontinued, and all of his other preadmission medications were restarted at discharge.
  
  
  CONCLUSIONS
  The addition of tizanidine in a patient receiving long-term treatment with lisinopril was associated with severe hypotension and bradycardia.
authors.affiliation: Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN, USA.
authors.forename: Susan W
authors.initials: SW
authors.lastname: Publow
authors.forename: Donald L
authors.initials: DL
authors.lastname: Branam
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000009:adverse effects; D000369:Aged, 80 and over; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects; D001919:Bradycardia / Q000139:chemically induced*; D003000:Clonidine / Q000009:adverse effects / Q000031:analogs & derivatives*; D004347:Drug Interactions; D006801:Humans; D007022:Hypotension / Q000139:chemically induced*; D017706:Lisinopril / Q000009:adverse effects*; D008297:Male; D012720:Severity of Illness Index
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D000806:Angiotensin-Converting Enzyme Inhibitors; C023754:tizanidine; D017706:Lisinopril; D003000:Clonidine