From the Guidelines
Methylene blue is a valuable rescue medication for hypotensive patients who are not responding to conventional vasopressors, particularly in cases of vasoplegic shock, with a recommended dosing of 1-2 mg/kg as an initial IV bolus, repeated every hour if needed, and a continuous infusion of 1 mg∙kg−1∙h−1 for vasodilatory shock, as stated in the 2023 American Heart Association guidelines 1.
Key Considerations
- The medication works by inhibiting nitric oxide synthase and guanylate cyclase, effectively counteracting excessive vasodilation that occurs in distributive shock states.
- Important considerations before administration include checking for G6PD deficiency, as methylene blue can trigger hemolysis in these patients.
- It should also be avoided in patients taking serotonergic medications due to the risk of serotonin syndrome.
- During administration, clinicians should monitor for potential side effects including blue discoloration of skin and urine, headache, nausea, and changes in pulse oximetry readings which may falsely indicate desaturation while actual oxygenation remains adequate.
Clinical Context
- Methylene blue is especially useful in vasoplegic syndrome following cardiopulmonary bypass, septic shock, and anaphylaxis when standard vasopressors like norepinephrine, vasopressin, or phenylephrine have failed to maintain adequate blood pressure, as supported by the 2023 American Heart Association guidelines 1 and other studies 1.
- The use of methylene blue in hypotensive patients has been described in case series and case reports as an effective adjunct to treat refractory vasodilatory shock after CCB overdose, although responses are mixed and the effects may be transient 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Utility of Methylene Blue in Patients with Hypotension
- Methylene blue (MB) has been shown to be effective in treating refractory hypotension in various studies 2, 3, 4, 5, 6.
- The medication works by inhibiting nitric oxide synthesis, which helps to increase blood pressure and reduce the need for vasopressors and inotropes 2, 3, 4, 6.
- In pediatric patients, MB has been used to treat vasoplegic shock, with favorable hemodynamic responses observed in several case reports and studies 2, 3.
- A meta-analysis of randomized controlled trials found that MB increased mean arterial pressure in hypotensive patients, with a weighted mean difference of 6.93 mmHg 4.
- MB has also been used in other perioperative scenarios, such as septic shock and anaphylaxis, with promising results, but additional studies are required to develop formative conclusions 6.
- The dosing and safety of MB in patients with hypotension have been evaluated in several studies, with no significant side effects reported 3, 6.
- Overall, the evidence suggests that MB may be a useful adjunctive therapy in patients with refractory hypotension, particularly in cases of vasoplegic shock 2, 3, 4, 5, 6.