Methylene Blue as Rescue Therapy in Refractory Hypotension Following Minoxidil Overdose

Introduction: Minoxidil, a topical agent for hair loss, can cause life-threatening vasodilatory shock when ingested in large quantities. Here, we present a case of refractory shock secondary to minoxidil overdose, successfully treated with methylene blue.


Description: A 19-year-old healthy male presented with severe hypotension (MAP < 50 mmHg) after ingesting ~180 mL of 5% topical minoxidil. He remained alert, but did not respond to fluid resuscitation or escalating doses of norepinephrine and vasopressin. Labs showed metabolic acidosis and elevated lactate, consistent with hypoperfusion. Echocardiography revealed normal cardiac function, and toxicology confirmed minoxidil ingestion. Minoxidil causes profound vasodilation by opening ATP-sensitive potassium channels in vascular smooth muscle. Due to its lipophilicity and large volume of distribution, it is non-dialyzable and can lead to vasoplegic shock resistant to standard therapy. With ongoing hypotension and suspected nitric oxide–mediated vasodilation, methylene blue was given as a bolus followed by a continuous infusion, which led to rapid MAP improvement and allowed for successful weaning of vasopressors. The patient remained stable and was discharged after three days with psychiatric support.

This case illustrates the potential role of methylene blue in reversing minoxidil-induced vasoplegia. By inhibiting the nitric oxide–cGMP pathway, it restores vascular tone when conventional vasopressors are ineffective. Early recognition and use of adjunctive therapy are crucial in managing such toxicologic emergencies.


Discussion: Minoxidil overdose can lead to severe and prolonged hypotension that may be unresponsive to standard therapies. Given its unique mechanism of action and non-dialyzable nature, early consideration of alternative agents is crucial. Methylene blue, through its inhibition of nitric oxide–mediated vasodilation, can be an effective adjunctive therapy as demonstrated in our case.