title: Acute tramadol poisoning and its clinical and laboratory findings.
abstract: BACKGROUND
  Tramadol is a centrally acting analgesic with opioid and nonopioid properties, which extensively used in the relief of mild to moderate pain. Tramadol poisoning is a common cause of acute pharmaceutical poisoning in Iran. There are a few studies about clinical and laboratory findings related to acute tramadol poisoning. Therefore, the aim of this study was to demonstrate the clinical and laboratory findings in tramadol acute poisoning cases.
  
  
  METHODS
  This was a retrospective descriptive study of patients with acute tramadol poisoning who referred to Loghman Hakim Hospital Poison Center during January to April 2012. Data such as patient's age, sex, time of ingestion, ingested dose, cause of poisoning, mean duration of hospitalization, patient's clinical presentations, laboratory findings, therapeutic measures, and patient's outcome have collected in a predesigned checklist.
  
  
  RESULTS
  A total of 144 patients including 111 men (77%) and 33 women (23%) with acute tramadol poisoning was included in this study. The mean ingested dose was 1971.2 mg (100-20000 mg). Seizure (47.91%) was the most frequent clinical symptom. Blood gas on admission showed pH (7.3 ± 0.1), PCO2 (49.7 ± 8.6 mmHg) and HCO3 (-) (24.1 ± 3.8 mEq/L), indicating pure acute respiratory acidosis may be occurred in tramadol-intoxicated patients. There were significant differences between tramadol-intoxicated cases with and without a seizure with regard to the time interval between ingestion and admission on hospital, ingested dose and PCO2.
  
  
  CONCLUSIONS
  Seizure and rise of PCO2 were the most findings in this study.
authors.affiliation: Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Rahimi
authors.affiliation: Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Soltaninejad
authors.affiliation: Excellent Center of Clinical Toxicology, Toxicology Research Center, Department of Clinical Toxicology, Loghman Hakim Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Shahin
authors.initials: S
authors.lastname: Shadnia
keywords: Clinical manifestations; laboratory; poisoning; seizure; tramadol