Methylene blue may be administered to a patient for a number of reasons. If an excessive dose is given then a number of toxic effects may develop.
Methylene blue is eliminated primarily in the urine, causing the urine to appear blue or green. This is to be expected and is not a toxic effect.
An increased risk for a toxic dose of methylene blue is seen:
(1) in neonates, associated with the low body weight
(2) parenteral administration
(3) renal insufficiency
Adverse effects of an overdose of methylene blue:
(1) Heinz body positive hemolytic anemia with hyperbilirubinemia
(2) phototoxicity with cutaneous bullae and/or desquamation
(3) methemoglobinemia
(4) dysuria (due to irritation of the urinary tract)
(5) nausea
(6) tachycardia and hypertension
(7) substernal chest pain
(8) anxiety
To read more or access our algorithms and calculators, please log in or register.
Specialty: Toxicology, Emergency Medicine, Critical Care
