Suspected cyanide intoxication after nitroprusside continuous rate infusion in a canine hypertensive emergency

Abstract This case report describes the clinical investigations and associated abnormalities of an 11‐year‐old, male, entire, Shih Tzu that presented for management of hypertensive emergency suspected to be due to a phaeochromocytoma affecting the right adrenal gland. The patient did not respond to incremental doses of amlodipine or the addition of phenoxybenzamine. Anti‐hypertensive management was escalated with an intravenous continuous rate infusion of nitroprusside for 29 hours. Several hours after the discontinuation of nitroprusside, marked changes in the patient's venous blood gas analyses raised the suspicion of cyanide toxicity secondary to the nitroprusside infusion.