Naphazoline intoxication managed with minimally invasive cardiac output monitoring.

Abstract

Naphazoline, a nonspecific alpha-adrenoceptor stimulant, is a potent vasoconstrictor used in nasal sprays, eye drops, and over-the-counter antiseptics. Naphazoline intoxication increases afterload by constricting the peripheral arteries, which can lead to complications including multiple organ failure. Although phentolamine, a nonselective alpha-adrenoceptor antagonist, and nicardipine, a calcium channel blocker, are used for the treatment of naphazoline intoxication, no established administration protocols currently exist. We present the case of a 32-year-old male with depression who ingested 150 mL of an antiseptic containing 0.1% naphazoline (equivalent to 150 mg of naphazoline). Five hours after ingestion, the patient was admitted to hospital exhibiting signs of naphazoline intoxication, such as bradycardia (46 beats/min), blood pressure of 166/122 mmHg, and peripheral cyanosis. We used the FloTrac™/EV1000™ system (Edwards Lifesciences, Irvine, CA, USA), a minimally invasive cardiac output monitoring system, to monitor systemic vascular resistance. The systemic vascular resistance index (SVRI) was elevated (4457 dyne.s/cm5/m2; nomal range: 1970-2390 dyne.s/cm5/m2) upon admission and initial treatment with continuous intravenous infusion of phentolamine led to SVRI normalization within 2 h. With the goal of maintaining SVRI normalization, continuous infusion with nicardipine was then started. At 10 h after treatment initiation, the nicardipine dose peaked at 9 mg/h (1.9 μg/kg/min). Treatment was discontinued 8 h later, and the patient was discharged on the fourth day without sequelae. In conclusion, the use of a minimally invasive cardiac output monitoring system to track vascular resistance can effectively guide the dosing of phentolamine or nicardipine in the treatment of naphazoline intoxication.

• Authors: Takatoshi Oishi, Masahiro Kashiura, Hideto Yasuda, Yuki Kishihara, Keiichiro Tominaga, Hiroyuki Tamura, Takashi Moriya
• Journal: The American journal of emergency medicine (Am J Emerg Med) Vol. 77 Pg. 233.e5-233.e7 (Mar 2024) ISSN: 1532-8171 [Electronic] United States
• PMID: 38155033 (Publication Type: Case Reports)
• Copyright: Copyright © 2023 Elsevier Inc. All rights reserved.

Chemical References

• Naphazoline
• Phentolamine
• Nicardipine
• Receptors, Adrenergic

Topics

• Male
• Humans
• Adult
• Naphazoline
• Phentolamine
• Nicardipine
• Cardiac Output
• Receptors, Adrenergic