From the Guidelines
Methylene blue can increase the risk of seizures, particularly in patients with a history of epilepsy or seizures. This is based on the guidance provided by the British Thoracic Society guidelines for the management of non-tuberculous mycobacterial pulmonary disease (NTM-PD) published in 2017 1. The guidelines caution against the use of methylene blue in patients with epilepsy or a history of seizures due to the increased risk of convulsions. Key considerations for the use of methylene blue include:
- Avoiding its use in patients with a history of seizures or epilepsy
- Monitoring patients closely for adverse effects, particularly those with renal impairment or liver disease
- Advising patients to report symptoms of visual impairment due to the risk of peripheral and optic neuropathy
- Being cautious when prescribing methylene blue to patients who consume large amounts of tyramine-rich foods or are pregnant. The increased risk of seizures associated with methylene blue is a critical consideration in its use, and healthcare providers should carefully weigh the benefits and risks of treatment, particularly in vulnerable populations.
From the Research
Methylene Blue and Seizure Risk
- The available evidence suggests that methylene blue does not increase the risk of seizures, but rather has anticonvulsant and neuroprotective effects 2, 3, 4.
- Studies have shown that methylene blue can protect against acute seizure and oxidative stress in various models, including kainic acid-induced status epilepticus and methylmalonate-induced seizures 2, 4.
- Methylene blue has been found to increase the latency to first onset of epileptiform activity, decrease the average duration of epileptiform events, and prevent deterioration of oxidative stress markers and glutamate levels 2, 3.
- The anticonvulsant and neuroprotective effects of methylene blue may be related to its potent antioxidant ability and influence on glutamate levels 2, 3.
Clinical Implications
- Methylene blue may be useful as an adjuvant for preventing or treating epilepsy in humans, particularly in cases where oxidative stress and glutamate imbalance are involved 3.
- The use of methylene blue in the treatment of neuropsychiatric disorders, including bipolar disorder, has shown promise, with antidepressant, anxiolytic, and neuroprotective effects reported 5.
- However, caution is needed when using methylene blue, particularly in relation to its inhibitory effect on monoamine oxidase A and potential interactions with other medications 5, 6.