Difficulties in diagnosing narcotic overdoses in hospitalized patients

OBJECTIVE: To describe the clinical presentation of narcotic overdose in hospitalized patients and to differentiate this circumstance from other conditions often misdiagnosed as overdose. DESIGN: Case series. SETTING: Two acute-care teaching hospitals. PATIENTS: Forty-three hospitalized patients who received naloxone for a clinically suspected narcotic overdose. INTERVENTIONS: Two investigators independently evaluated each incident to determine whether the patient had a narcotic overdose. The patients were judged to have had an overdose if caregivers documented an immediate improvement in mental status, respiratory rate, or blood pressure after naloxone administration. MEASUREMENTS: The clinical presentation of a narcotic overdose in hospitalized patients was defined. Conditions misdiagnosed as an overdose were determined. MAIN RESULTS: Symptoms improved rapidly with the administration of naloxone in 28 incidents (65 percent) and were designated overdose. In 15 other instances there was no improvement in symptoms; these patients were designated nonoverdose. Only half of the overdose patients had a respiratory rate < 8 breaths/min immediately prior to naloxone administration. Only two of the overdose patients had the classic triad of symptoms (respiratory depression, coma, and pinpoint pupils). Other overdose patients had only one or two of the classic signs. The clinical presentation of narcotic overdoses in hospitalized patients did not include respiratory depression, hypotension, or coma in the majority of patients. All overdose patients showed a decrease in mental status. The majority of nonoverdose patients had pulmonary conditions that were misdiagnosed as a narcotic overdose. CONCLUSIONS: Narcotic overdoses in hospitalized patients seldom fit the classic description. The lack of respiratory depression does not mean the absence of a narcotic overdose. Patients who receive narcotics and develop a significant decrease in mental status should be evaluated for a possible overdose. Pulmonary, neurologic, cardiovascular, and electrolyte abnormalities often are misdiagnosed as a narcotic overdose in hospitalized patients.