Methylene Blue Drug Interactions: What Not to Take With It

The most important methylene blue interaction is with drugs and supplements that raise serotonin. Ramsay and colleagues (British Journal of Pharmacology, 2007) showed that methylene blue is a potent inhibitor of monoamine oxidase A, the enzyme that clears serotonin, so combining it with antidepressants and other serotonergic products can cause serotonin syndrome. That is a rare but potentially serious reaction, and it is the interaction the FDA warned about in a 2011 safety communication. Beyond serotonin, a few people should avoid methylene blue no matter the dose: anyone with G6PD deficiency, anyone who is pregnant or nursing, and children.

Below we go through which medications and supplements matter and why, what serotonin syndrome looks like, why the gap between a serotonergic drug and methylene blue is your prescriber's call, and a few habits that help if your doctor agrees methylene blue is right for you.

• Serotonergic drugs are the main risk. SSRIs, SNRIs, MAOIs, tricyclics, and similar medications can combine with methylene blue to trigger serotonin syndrome.
• Some people should avoid it completely. G6PD deficiency, pregnancy, and nursing are firm contraindications, and it is not for children.
• Timing is a medical decision. Any washout between a serotonergic drug and methylene blue has to be set by your prescriber, never improvised.

Important: This article is educational and is not medical advice. Do not start, stop, or combine any medication based on it. Review the full adverse medications list and speak with your healthcare provider or pharmacist before using methylene blue.

Here are the main methylene blue drug interactions, grouped by drug class. Each line names its source: the FDA prescribing information for Provayblue (methylene blue injection), the FDA's 2011 drug safety communication, or the Drugs.com interaction checker. These sources were written about medical methylene blue, mostly given by IV, so read them as what those sources say, not as advice from us. This post explains the classes. To look up one drug by name, use the full adverse medications list.

Brand names for the antidepressants come from the medication table in the FDA 2011 communication. Drugs.com ratings were checked on November 3, 2026.

If you only read one part, read this. Here is what the sources above say not to combine with methylene blue, and who they say should not take it at all.

• SSRIs, SNRIs, MAOIs and opioids, including tramadol. The Provayblue boxed warning says to avoid using them together with methylene blue.
• Bupropion, buspirone, mirtazapine, clomipramine, linezolid and dextromethorphan. The Provayblue label names each of these in its drug interactions section.
• Triptans, stimulants such as Adderall, ondansetron, St. John's wort, 5-HTP and tryptophan. Drugs.com rates each of these as a major interaction.
• A serotonergic drug started right after methylene blue. The Provayblue label says to tell patients not to take serotonergic drugs within 72 hours after the last dose.
• People with G6PD deficiency. The Provayblue label lists this as a contraindication because of the risk of hemolytic anemia. It also lists severe hypersensitivity to methylene blue or other thiazine dyes.
• Pregnancy and breastfeeding. The Provayblue label says it may cause fetal harm and advises stopping breastfeeding for up to 8 days after treatment.

Do not stop or change a prescription on your own. If you take anything on this list, talk to the prescriber who manages it first. For any drug not named here, look it up on the full adverse medications list, which links each entry to its Drugs.com page.

Serotonin is the main concern because of one enzyme. Ramsay and colleagues (British Journal of Pharmacology, 2007) showed that methylene blue is a potent inhibitor of monoamine oxidase A, or MAO-A, the enzyme that breaks serotonin down in the brain. That is why methylene blue is treated as a monoamine oxidase inhibitor for interaction purposes, in the same category as the older antidepressants doctors never pair with serotonin-raising drugs. When MAO-A is switched off at the same moment another drug is driving serotonin upward, serotonin can accumulate in the nervous system faster than the body can clear it.

That build-up is serotonin syndrome. Boyer and Shannon (New England Journal of Medicine, 2005) describe it running from mild to life-threatening: agitation, sweating, a racing heart, shivering, and muscle twitching on the milder end, and high fever, muscle rigidity, and confusion at the severe end, which is a medical emergency. This has happened in real patients. A 2022 case report in the American Journal of Case Reports describes serotonin syndrome after surgery in a patient given methylene blue, and a 2025 Cureus study found that a large share of surgical patients given methylene blue were also on a serotonin-raising drug. Reports like these led the FDA to issue its 2011 safety communication.

Antidepressants are the group that matters most, and the medications involved are common enough that people do not always think of them as serotonin drugs. If you take anything in the categories below, the safe assumption is that it should not be combined with methylene blue unless a doctor who knows your full history specifically clears it and supervises the timing. The list is broader than antidepressants alone.

Medication classes that raise serotonin

• SSRIs (selective serotonin reuptake inhibitors), such as sertraline, fluoxetine, escitalopram, citalopram, and paroxetine
• SNRIs (serotonin-norepinephrine reuptake inhibitors), such as venlafaxine and duloxetine
• MAO inhibitors, such as phenelzine, tranylcypromine, selegiline, and isocarboxazid
• Tricyclic antidepressants, such as amitriptyline and nortriptyline
• Other serotonergic agents, including bupropion, trazodone, lithium, triptans for migraine, tramadol, dextromethorphan, and some anti-nausea drugs such as ondansetron

The practical rule is simple. If a medication is used to treat depression, anxiety, OCD, migraine, chronic pain, or nausea, assume it could raise serotonin and check with your pharmacist before going anywhere near methylene blue. Brand names change and combination products can hide these ingredients under unfamiliar labels, so have a pharmacist read your actual prescription list rather than going from memory.

A few other categories are worth raising with your provider, especially if you take them every day. The FDA label for methylene blue injection (Provayblue) lists hypertension among its reported reactions, so anyone managing blood pressure should clear it with their prescriber first. There is also a smaller set of drugs that affect how blood carries oxygen, including certain topical anesthetics and other agents linked to methemoglobinemia. And any medication with a narrow margin between a helpful dose and a harmful one deserves a second look.

None of this means methylene blue is dangerous for the average healthy person. It means that before you add it to medications you already take, get a quick medication review. A pharmacist can usually do this for free in a few minutes and will catch anything the categories above missed.

Stimulant medications are one of the most common questions we see, and they deserve their own section. The Vyvanse (lisdexamfetamine) prescribing information, as published on DailyMed, lists patients taking monoamine oxidase inhibitors, including "intravenous methylene blue," among those who should not use the drug because of an increased risk of hypertensive crisis. That wording refers to intravenous methylene blue as a medical treatment, not to an oral supplement, but it shows why the combination gets flagged. Methylene blue inhibits monoamine oxidase A, and that MAOI-like action is the reason stimulants come up at all. See the Vyvanse prescribing information on DailyMed for the exact language.

Drugs.com is the interaction reference we use for the rest of the list. Our full adverse medications list links each row to its Drugs.com page, and it marks amphetamine (Adderall), lisdexamfetamine (Vyvanse), methylphenidate (Ritalin, Concerta), and bupropion (Wellbutrin) with a "Major interaction" label. Bupropion is an antidepressant rather than a classic stimulant, but it is one of the names people search for alongside them.

If you take any prescription stimulant, ask the prescriber who manages it before adding methylene blue. Do not stop or change your dose on your own to make room for a supplement, and do not assume that spacing the two apart makes the combination safe.

Supplements can interact too, and they are the ones people forget to mention. Several popular supplements raise serotonin or act on the same pathways as antidepressants. St. John's Wort, the herbal product widely used for low mood, is the clearest example: Boyer and Shannon (New England Journal of Medicine, 2005) list it among the substances tied to serotonin syndrome, and it should not be combined with methylene blue. The same caution applies to direct serotonin precursors such as 5-HTP and L-tryptophan, to SAM-e, and to the mood and sleep nootropic stacks built around tryptophan-rich ingredients. Our rule of thumb: if you take a supplement because it lifts your mood or helps you sleep, treat it like a serotonergic drug and check before combining it with methylene blue.

People with glucose-6-phosphate dehydrogenase deficiency, usually shortened to G6PD deficiency, should not take methylene blue at all. The FDA label for Provayblue lists G6PD deficiency as a contraindication because of the risk of hemolytic anemia, the destruction of red blood cells. G6PD deficiency is an inherited condition that leaves red blood cells less able to handle oxidative stress, as the StatPearls review on G6PD deficiency explains. For this group it is not a question of dose; it is a reason to avoid methylene blue.

G6PD deficiency is more common than most people think. The StatPearls review describes it as one of the most common enzyme deficiencies in the world, seen more often in people of African, Mediterranean, Middle Eastern, and Southeast Asian heritage, and many people who have it have never been tested. If you or close relatives have a history of unexplained anemia, episodes of jaundice, or a bad reaction to fava beans or certain antimalarial medications, those are exactly the clues that warrant a conversation with your doctor and a simple blood test before you consider methylene blue.

Methylene blue is not for pregnancy, breastfeeding, or children, at any dose. The FDA label for Provayblue warns that it may cause fetal harm when given to a pregnant woman, and it advises stopping breastfeeding during and for up to 8 days after treatment. Lowering the amount does not change that.

If you are pregnant, trying to conceive, nursing, or looking for something to give a child, methylene blue is not the right product. The most useful thing we can tell you is to stop there and ask your own clinician about other options.

People sometimes ask whether they can simply space methylene blue and their antidepressant a few hours apart, the way you might separate two supplements that compete for absorption. That does not work here. Many serotonergic drugs, along with the active byproducts they leave behind, linger in the body for days and in some cases weeks, so putting a few hours between doses does almost nothing to lower the risk. The serotonin-raising effect is still firmly in place when the methylene blue arrives.

In clinical settings the accepted approach is a washout period, meaning a defined stretch of time after stopping the serotonergic medication before methylene blue is introduced, and the right length depends entirely on the specific drug and the person taking it. Setting that window is a medical decision, partly because stopping an antidepressant on your own carries risks of its own, from withdrawal effects to the return of the condition it was treating. Any washout belongs with the prescriber who manages that medication.

If none of the medications, supplements, or conditions above apply to you, these habits still make sense and take very little effort:

• Get a pharmacist medication review. Bring your full list, prescription and over-the-counter, and ask specifically about serotonergic interactions.
• Start low. Lower doses reduce the chance of side effects across the board, so there is rarely a reason to rush upward.
• Use a clean, tested product. Interaction risk is about the molecule, but purity matters too. We use USP-grade methylene blue, third-party tested by independent labs.
• Know the warning signs. Agitation, a rapid heartbeat, sweating, shivering, muscle twitching, or confusion after a dose are reasons to stop and seek medical care promptly.

Used this way, with a clear medication list, a low dose, a tested product, and an eye on how you feel, most healthy adults can use methylene blue sensibly. For specifics on amounts once you have confirmed it is right for you, see our methylene blue dosing guide and our broader look at whether methylene blue is safe.

Read this part first, whether you use drops or capsules. Each line below names its source. The FDA prescribing information for Provayblue (methylene blue injection) was written about IV hospital use, so read it as what that label says, not as advice from us.

• SSRIs, SNRIs, MAOIs and opioids, including tramadol. The Provayblue label boxed warning says to avoid using them with methylene blue because of the risk of serious or fatal serotonin syndrome.
• Bupropion, buspirone, clomipramine, mirtazapine, linezolid and dextromethorphan. The Provayblue label names each of these in its drug interactions section.
• St. John's Wort, 5-HTP and L-tryptophan. Our adverse medications list shows Drugs.com rating each of these as a major interaction with methylene blue.
• G6PD deficiency. The Provayblue label lists it as a contraindication because of the risk of hemolytic anemia.
• Pregnancy and breastfeeding. The Provayblue label says it may cause fetal harm and advises stopping breastfeeding for up to 8 days after treatment.

For any drug not named here, look it up on the full adverse medications list, and talk to your healthcare provider before starting methylene blue in any form.

Every Nutricel product uses USP-grade methylene blue and is made in an GMP certified facility in the United States, and our capsules are third-party tested by independent labs. The difference between them is what goes in alongside the methylene blue.

Blue Boost is our core formula: 12mg of methylene blue per capsule with Vitamin C Ester and organic cacao. If you mainly want methylene blue itself, start here.

Blue Immune combines methylene blue with copper, magnesium, NAC, grass-fed beef liver, and camu camu for fatigue and cellular energy support, based on the Root Cause Protocol.

Blue Shroom pairs methylene blue with six organic mushroom extracts including lion's mane, reishi, cordyceps, chaga, shiitake, and turkey tail.

Blue Renew is built around GlyNAC with collagen and creatine, aimed at longevity and brain function as you age.

Blue Remove combines zeolite, curcumin, and nattokinase, aimed at circulation and the body's normal inflammatory response.

Blue Liquid is USP-grade methylene blue in a dropper bottle (1%, 10mg per mL), for people who prefer liquid and want to adjust in small steps.

Methylene blue has one interaction that matters most and a short list of people who should avoid it altogether. Get those right and you have dealt with the main risks; ignore them and the risk is real. Everything in this guide comes back to one habit: check before you combine.

• The main interaction is with serotonergic drugs, because methylene blue inhibits MAO-A (Ramsay and colleagues, 2007) and can contribute to serotonin syndrome.
• SSRIs, SNRIs, MAOIs, tricyclics, and serotonergic supplements such as St. John's Wort are the key things never to combine it with.
• G6PD deficiency, pregnancy, and nursing are contraindications, and methylene blue is not for children.
• Any washout between a serotonergic medication and methylene blue has to be set by your prescriber, not improvised at home.
• When in doubt, a free pharmacist medication review is the fastest way to know whether methylene blue fits your situation.

Mechanism and Serotonin Interaction

Clinical Reports and Reviews

Interaction Labels and Ratings

Drug Profile and Contraindications

Sam Carlson, Marketing Developer at Nutricel

Sam is a marketing developer at Nutricel who writes the Nutricel Insights series to help our customers understand methylene blue and make informed choices, translating the published research into plain language. Sam is not a medical professional, and these articles are intended as education rather than medical advice. Every figure in this piece is tied to the peer-reviewed studies and FDA guidance listed in the references, and you should always speak with your healthcare provider before starting any supplement.