A case of Naphazoline intoxication after the Ingestion of ophthalmic drop

Introduction: The imidazoline derivative naphazoline belongs to the a2-adrenergic agonists which are used in over-the-counter eye and nasal preparations because of its vasoconstrictive and decongestive properties. We reported a case of accidental oral ingestion naphazoline eye drop.Methods: A 32-year-old man with methadone addiction, accidentally ingested all of Naphazoline eye drop of his housewife; instead of methadone; 7 hours before admission. About 4 hours later he suffered progressive pulsatile headache. Shortly after, he presented other manifestations: constant abdominal pain, dizziness, weakness and two times vomiting. He had normal defecation. When he referred to our ward, he was confused. With dilated pupils normal vital signs (blood pressure: 150/90 mmHg, Heart rate=73 beat/min, respiratory rate=14cyle/min and temperature=37.2 oral). Other finding of examination included: soft non-tender abdomen in palpitation with hypoactive bowl sounds (3-5 sounds/min), cool and pale extremities, and his glucometer blood sugar level was 112 mg/dl. An half hours after admission he suddenly developed sinus bradycardia (heart rate <40, and reduced to 15-20 beat/min) and hypertension (BP=208/118 mmHg), however his level of consciousness did change. He treated by infusion of nitroglycerin (up to 10 μg/kg/min); however his BP did not reduced properly up to two hours. After two hours his BP returned to 110/70 and infusion of nitroglycerin was hold and he did not received again. His bradycardia treated by 0.5mg Atropine and his HR raised to 103 beat /min. due to his recurrent bradicardia (HR<35-45) he was managed by infusion of 1mg/hour of Atropine up to tomorrow morning (22 hours after Naphazoline ingestion ). His headache and then abdominal pain gradually resolved during his hospital stay. On the tomorrow morning he was alert and his vital signs were in normal range (HR=88, BP=115/85, RR=16) and had soft non-tender abdomen with 6-8 bowel sounds per minute and was discharged.Results: We found few cases of Naphazoline intoxication in literature and majority of them were overdose secondary to topical use of solution in child, however, there are 2 cases of oral ingestion of solution. Our case is the only case who ingested all of ear drop (10cc). He presented typical manifestation of Naphazoline, peripheral a2-adrenergic agonists, intoxication include; bradycardia, hypertension, dizziness, reduced bowel motility, loss of consciousness, mydriasis and peripheral vasoconstriction.Conclusion: Ingestion of Naphazoline could be life threating by bradycardia and raising the blood pressure.