Course and therapy of intoxication with imidazoline derivate naphazoline.
OBJECTIVE
Imidazoline derivatives like naphazoline have a firm place in diagnostics and therapy of otorhinolaryngology because of their vasoconstrictive and decongestive properties. Their alpha-adrenergic potential could induce not only local but also systemic side effects like hypertension and tachycardia which can increase a life-threatening intoxication. Signs of imidazoline intoxication are excessive systolic and diastolic hypertension and hypotension, bradycardia with arrhythmia, respiratory depression, excitation or severe CNS depression.


METHODS
The typical course of an intoxication and its sufficient therapy is reported by means of two cases of intraoperative application of naphazoline for hemostasis.


RESULTS
In case of overdosage or intoxication, symptomatic drug therapy with intravenous administration of 5 mg phentolamine for adults and 1 mg phentolamine for infants has to be done. Phentolamine, an alpha-adrenoceptor antagonist, acting against peripheral and central side effects has to be used because no specific antidote is available.


CONCLUSIONS
Especially pediatric otorhinolaryngologists have to know about symptoms and therapy of an intoxication after application of naphazoline. Particularly with children, a narrow therapeutic to toxic window can be observed in this frequently used drug.
Wenzel
S
S
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany. swenzel@uke.uni-hamburg.de
Sagowski
C
C
Laux
G
G
Kehrl
W
W
Metternich
F U
FU
D000233:Adenoidectomy; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000009:adverse effects*; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000139:chemically induced; D001919:Bradycardia / Q000139:chemically induced; D002648:Child; D003251:Constriction, Pathologic / Q000139:chemically induced; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D006973:Hypertension / Q000139:chemically induced; D007275:Injections, Intravenous; D008297:Male; D009278:Naphazoline / Q000008:administration & dosage / Q000009:adverse effects* / Q000737:chemistry; D009305:Nasopharynx; D019106:Postoperative Hemorrhage / Q000188:drug therapy*; D014068:Tonsillectomy
D000316:Adrenergic alpha-Agonists; D009278:Naphazoline