I created this blog for one simple purpose—to help people who have had a serious, adverse reaction to Flagyl (aka, metronidazole), so they have a place to read about the condition and to find answers to questions that no medical professional was willing to help me find.  What you have has a name: Metronidazole Toxicity.  In group, we sometimes call this “getting moxxed.”

I am not a doctor; I was a patient.  All of my posts are based on my personal experience and information I found across the internet.  You will have to decide what to take from this site, but I hope it helps you through your recovery.

Make sure to check out “Treatment” that will go into more detail about the mechanism behind metronidazole toxicity and ways to possibly improve symptoms!

Here is the quick sum-up of my experience with metronidazole:

In June of 2015, I was diagnosed with c diff (a gut bacteria), and prescribed metronidazole, 500mg.  Five days into taking it, I had a serious, adverse reaction, including difficulty walking, slurred speech, dizziness, extreme fatigue and feeling faint.  What followed was six weeks of debilitating fatigue, brain fog, depression, severe insomnia, muscle twitches, nausea, zero appetite, coughing, difficulty swallowing, shortness of breath, brain zaps (feels like lightning bolts surging through my skull), flushing face, chills, hand tremors, neck pain, and the absolute worst anxiety I’ve ever experienced (sound familiar?).

But what was worse was that the doctors flat-out did not believe me.  They insisted that the antibiotic was “out of my system” less than a week after my last dose; therefore, it couldn’t be the drug.  Of all the things that happened to me, this was the most disheartening, and if you are suffering from the same situation with your doctors, I am so sorry.  I hope that this website helps you better understand what you have and what to expect.

Nowadays, most of my symptoms have resolved and the ones that didn’t are minor and infrequent.  I’m back to my normal life.  The first two months were the hardest, and it slowly improved over about nine months, and then, when introducing the treatment plan listed on the Treatment page, things really turned around.

Most of all, this experience has left me disillusioned by the health care system.  If you are experiencing even some of the symptoms I’ve addressed, you are probably experiencing some form of metronidazole toxicity.  Your doctors don’t believe you—I do.  I believe you because I went through it, researched it, and now, I want you to have an easier time than I did in knowing what this condition is about.

If you wish to learn more about my experience with metronidazole toxicity and how the medical community responded, I have an article published in the online magazine Hormones Matter:

Metronidazole Toxicity and Doctor Denial

In addition, if you or are loved one are suffering from metronidazole toxicity, we have a support group on Facebook: The Metronidazole Toxicity Support Group.  This group is not a Wikipedia page; it is a safe place for people suffering from this condition to discuss it with others going through a similar experience.  Make sure to answer both questions; otherwise, the request to join will be denied (we get a lot of bots!).

The Most Common Questions About Metronidazole Toxicity

1.     How common is metronidazole toxicity?

According to Oxford University in their 2021 article, “Metronidazole-associated Neurologic Events: A Nested Case-control Study,” at its most optimistic number, metronidazole-induced neurotoxicity and/or neuropathy occurs in roughly 1 in 400 patients taking the drug, leading to hospitalization.  This is a vast underestimation, as even in our metronidazole toxicity support group, 88% of members were never hospitalized due to their toxicity, no matter the severity of symptoms.  Even the Oxford article notes that their findings are probably under-estimating the true number, but 1 in 400 (or .25%) gives us a baseline.

2.     Will I recover from metronidazole toxicity?

Most likely, yes.  While you certainly feel awful right now, the prospects for recovery are relatively good and (for most people) seem to happen weeks to a few months after discontinuation of the drug.

People who are suffering from strictly mood changes have an especially higher chance of complete recovery.  People who suffer from motor control problems (difficulty walking, slurred speech, etc) and/or autonomic dysfunction (issues with the “automatic” operations in the body like breathing, heart rate, digestion), have a slightly less chance of complete recovery but it’s still the outcome for the majority of patients.  People with neuropathy (tingling, numbness, electric shocks in the limbs and/or face) do struggle to recover fully from the neuropathy itself, but many still do eventually.

If nothing more, you should greatly improve over time.

3.     What is happening that’s causing this adverse reaction?

Essentially, metronidazole goes everywhere in the body, including the brain.  Typically, when someone has an adverse reaction to metronidazole, it is due to the drug’s negative effects on the brain (specifically the cerebellum and brain stem) and the nerves throughout the body.

While the symptoms of metronidazole toxicity are vast and appear very random, most fall into four main categories:

• Cerebellar Dysfunction
• Dysautonomia (dysfunction of the brain stem)
• Altered Mental State (see my page on Anxiety)
• Neuropathy

I have a video that goes into all the symptoms of metronidazole toxicity, which can you view here (pardon my slightly-smirky face–I’m not photogenic!):

In medical literature, it is even noted that metronidazole can cause white matter lesions, which is damage to the brain, and can be seen on an MRI.  However, there is poor correlation between the resolution of these lesions and resolution of symptoms, meaning that the lesions are just another symptom of metronidazole toxicity, not the underlying cause of the toxicity.  For most patients, if they had lesions, the lesions disappear as quickly as a few days after discontinuation of the drug, even is symptoms persist.

Due to doctors only writing about metronidazole toxicity if lesions are discovered in their patients, this leaves a skewed and inaccurate view that the lesions are more common and a misguided test for doctors to depend on when diagnosing the toxicity.  In other words, you don’t have to have lesions to be suffering from metronidazole toxicity; symptoms should be used to diagnose instead.

If you want to learn more about metronidazole toxicity in medical literature, I have a video that goes into that here, as part II of my video series on YouTube.

4.     How long will it take me to recover?

This is a really tricky question.  We have people ask this in support group frequently, but the issue is that people who recover fully don’t need a support group, so many leave or become inactive in group without sharing their outcomes.

Ultimately, it depends on this question: how much dysfunction did metronidazole cause vs. how much damage did metronidazole cause?

If you strictly have an altered mental state and no other symptoms, it’s very possible your symptoms are due to dysfunction, so when that dysfunction resolves, you will recover and it can happen quickly.  However, if you have any motor control issues or issues with your autonomic nervous system (all the “automatic” things in your body, like digestion, blood pressure, breathing, etc), then it’s very possible there has been at least some damage.  Neuropathy is, unfortunately, all damage, which means it has the hardest time healing.

What this means is that, over time, you’ll probably see improvement in symptoms, some being very fast and others very slow.  Some symptoms might not resolve fully, which is what happened to me, but I’m still here, I’m back to my normal life, and my remaining symptoms are more a nuisance 99% of the time.

On top of that, flare ups are very common.  In fact, they happen in over 90% of metronidazole toxicity sufferers.  This means you will experience good and bad days as you’re healing.  Don’t be surprised if one day, you feel almost normal and the next, you’re back in bed.  This doesn’t mean you’re not improving, but it’s a bumpy road.

5.     But why would I have flare ups of my symptoms?

I know, right?  Out of all the bizarre things, but there’s a good reason why this happens, and it’s because of the primary mechanism behind metronidazole toxicity…that metronidazole toxicity is actually metronidazole-induced thiamine deficiency disease.  Thiamine is also called vitamin B1, and it is an essential vitamin your body needs to properly function—without it, your mitochondria (the part of your cells that make energy) become dysfunctional and that dysfunctional can lead to damage.

Between June 2015 and the end of 2017, I had several mild flare ups and 2 major ones, including my last in November of 2017.  It was at this time that I happened upon a medical textbook called “Thiamine Deficiency Disease, Dysautonomia, and High-Calorie Malnutrition.”  Looking back at my own research, it became clear that metronidazole destroys the thiamine in your body; when you are deficient in thiamine, you have:

• Cerebellar Dysfunction
• Autonomic Dysfunction (brain stem dysfunction)
• Altered Mental State
• Neuropathy

Sound familiar?  Thiamine deficiency can even cause lesions on the back of the brain, and medical literature is continuously compared metronidazole toxicity and another type of neurological disorder, Wernicke’s Encephalopathy, due to their striking similarities in symptoms and the appearance of brain lesions.  Wernicke’s is directly caused by thiamine deficiency.

Most likely, you cannot correct a deficiency this great by just eating thiamine-rich foods; it requires months of high-thiamine supplementation and magnesium supplementation.  But this is actually good news, because this means that if you are having metronidazole toxicity issues like flare up’s, there’s something you can do about it!

Please visit my “Treatment” page to learn more and get your quality of life back!

6.     Can I recover without thiamine and magnesium supplementation?

Yes, it’s possible but unlikely.  Your mitochondria have three key enzymes that require thiamine to function and if they are not damaged due to thiamine deficiency, then once you stop metronidazole and begin eating normally, you will slowly restore the thiamine, and your enzymes will not longer be starved.  But if the enzymes are compromised in any way—if the mitochondria aren’t capable of functioning properly or your gut is not capable of absorbing enough thiamine due to bad gut flora, SIBO or just imbalance due to antibiotics—then that little bit of thiamine you get in food just won’t suffice right now.

One thing is true, the longer you wait to fix this deficiency, the harder it will be to fix down the road.  Right now, your enzymes are starved for thiamine and are not functioning correctly—that dysfunction can damage the body, especially the back of the brain and the nerves.  Restoring thiamine can stop the dysfunction, but any damage will need time to heal.  The longer you have the deficiency, the higher the chance of it causing damage.

Again, I am not a doctor, but my research is supported by Dr. Derrick Lonsdale, the lead author of the medical textbook, “Thiamine Deficiency Disease, Dysautonomia, and High Calorie Malnutrition.”  In the end, you will have to look into the research I’ve provided and make your own decision on what is best for you.  The treatment is cheap and you can start TODAY (I’m not getting paid a cent, by the way–I just want you to get better as I have).

As part III of my YouTube video series, I have gone through all aspects of metronidazole-induced thiamine deficiency disease, including: why metronidazole destroys thiamine, what this means for your body, the explanation for flare ups in more detail, paradoxical reactions to thiamine, thiamine testing (and why it stinks), and lastly, how to supplement thiamine and why.  Please check it out here:

And the most mind-numbing question of all…

7.     Why won’t my doctors believe me???

This is probably the most frustrating thing of this whole situation; you know you’re not well.  You know you’re not yourself—the anxiety, the fatigue…you feel like you’re dying sometimes, and your doctor refuses to accept that this could be due to the drug.  They might even refuse tests or insist you’re mentally ill, with or without a previous medical history of mental illness.  I went through this myself and it is terrifying.

Here is the bottom line—doctors are not trained to recognize, diagnose and treat adverse drug reactions.  Again, doctors are not trained to diagnose and treat your condition.

We did a survey in our support group and the results are in: 84% of our metronidazole toxicity sufferers are not believed by their physicians.  Besides the toxicity itself, denial of doctors is the most discussed topic in our support group.

I wrote about my experience with this phenomenon for the magazine Hormones Matter called, “Metronidazole Toxicity and Doctor Denial.”  Dr. Derrick Lonsdale was kind enough to contribute to this article with some points about the connection between metronidazole and thiamine deficiency disease.

Adverse drug reactions are responsible for 100,000 deaths in the US every year.  This does not include the 20,000 people who die from illegal drug use; this does not include those who abused or used their prescription drugs incorrectly (a death rate that has drastically increased recently due to the opiate crisis–this number does not represent those patients).

—I want to emphasize here that, with all the research I’ve done on metronidazole toxicity, I’ve only found two people who died due to its effects.  One was a rare case of liver function issues, nothing to do with the brain, and while the other was due to metronidazole toxicity, but at very high doses through an IV.  The patient continued treatment for over two weeks after toxicity symptoms began.  So can it happen?  Yes, but it seems to be rare and if you stopped taking the drug, is highly unlikely.

The harm caused by drug reactions has been called the “silent epidemic” due to the mortality numbers (and those left permanently disabled) challenging that of Alzheimer’s patients and many other common, life-threatening conditions.  Twice as many people die from adverse drug reactions each year than those who die in car accidents.

And yet, there is no mandate for doctors to report an adverse drug reaction to the FDA.  Even if they suspect or have even confirmed a diagnosis, reporting those effects is 100% voluntary.  Due to this lack of regulation, only 1% to 10% of adverse drug reactions are reported (10% being a really optimistic number).

This is why doctors do not believe a drug can cause such harm to their patients.  Not only are drugs their top weapon to combat disease, but doctors also lack the education to understand just how dangerous prescription (and even non-prescription) drug can be.  Because there is no regulation, they are misinformed about the dangers, and we, the patients, suffer the consequences of their ignorance and denial.

This isn’t entirely their fault, however.  It’s part of a larger problem.  Let’s break it down.

The FDA:  The FDA is directly funded by the pharmaceutical companies, not taxpayer money.  A quarter of all FDA employees will end up working for a pharmaceutical company.  There are thousands of employees at the FDA who are there to approve new drugs; there are–literally–about 50 employees there who monitor the over 3,000 drugs currently on the market.  They are underfunded, understaffed and their money comes from the companies they are supposed to regulate.

The Pharmaceutical Companies:  As for the pharmaceutical industry, they give a lot of money to medical universities.  At Hazard, there is a lecture hall named after Pfizer, Inc. (one of many medical buildings named after pharmaceuticals).  Many medical journals, including the Journal of the American Medical Association, advertise and take money from pharmaceuticals.  And when these companies conduct their clinical trials on new drugs, they do not have to disclose any trial to the FDA where the drug failed to work better than placebo (aka, a sugar pill).  They have the right to conduct 30 trials on a drug, and only disclose the 3 trials to the FDA where the drug happened to work better.

For every nine doctors, there is one pharmaceutical sales rep, and when doctors take gifts from sales reps, those doctors are six times more likely to prescribe new, more expensive drugs to the patients.  This problem is so widespread that even our current Congress (yes, 2017), put restrictions on it due to the corruption.

Of course, there is the strange mentality that doctors are just too plain smart to be influenced by “Big Pharma” and that advertisements and gifts only work on us stupid people.  In the US every year, the pharmaceutical companies spend 4 billion dollars marketing directly to patients (and if it didn’t work, they wouldn’t do it, right?).  They spend 23 billion dollars marketing directly to doctors.

To learn more about this phenomenon, watch the video below–it sums it up quite nicely.

Even if a doctor doesn’t give in to marketing ploys, they are still dealing within a group of peers who regularly do.  They are taught the benefits of drugs, and the adverse effects of them are either glossed over or omitted completely.  The only doctors who seem to understand this issue are ones who have experienced a drug reaction themselves.

The Human Factor.  In addition to the issue above, there is a basic, human element at work here.  Everyone, including doctors and patients, believe that drugs are supposed to heal.  That is their only purpose.  So when a drug not only doesn’t work, but actually harms…this causes a phenomenon called cognitive dissonance.  It creates a contradiction in a person’s thought process “The drug is meant to help, so how can it have caused harm?”  This contradiction causes psychological stress–it threatens the person’s belief and can lead to another issue, “Identity Protective Cognition.”

Here is a lighthearted video about this affect:

Telling a doctor (or anyone) a trivial correction to their thought process is one thing–most people can handle being slightly wrong.  But doctors exist to help their patients recover from disease or injury, so when you tell a doctor their treatment harmed you instead of healed you, you are threatening their identity.

Doctors really do want to help their patients, but just like all humans (including you), they are more interested in protecting themselves.

Therefore, it’s easier to deny the problem or even gaslight the patient (“You’re not sick from this drug I gave you!  You’re just an anxious and depressed person.”).  This is a recipe of a toxic situation, especially when you, the patient, are dealing with a serious medical condition that needs treatment and have no real power in the medical hierarchy to change minds that don’t want to listen.

This is especially difficult if you are dealing with an adverse drug reaction that causes psychiatric symptoms such as depression and anxiety.  It is difficult to test and diagnose, and if physicians cannot find anything physically wrong with you, they can easily assume it’s “all in your head.”

I wish I had a good solution here for this problem.  The only thing I can say is this—it is NOT you.  It is the drug.  And it will get better.  You will have to be patient with yourself and know that you’re not the problem.  You are right—they are wrong.  It’s as simple as that.

I hope this helps you as you continue to recover from this horrible reaction.  I want to say again that I’m so sorry you’re going through this, and I wish you the best in your recovery.

Sources for this blog post:

• To learn more about metronidazole toxicity, click here for the link to a accumulative case study (it’s where a lot of my information came from).
• Here is another link to another study–click here.
• Here’s another one: click here.
• Another:  click here.
• Another case (this one talks about longer resolution of all symptoms, so it’s beyond 3 months out for you, there’s still hope of recovering completely).  Click here.
• To see that you are NOT alone, visit askapatient.com to see other people’s experience going through this horrible reaction.  There are two main listings there, one for Flagyl (the brand name) and one for metronidazole (the generic name).
• For information about adverse drug reactions in general, click here.
• “When Medicine Hurts: The Silent Epidemic” – click here.
• “The Epidemic of Silence with Adverse Drug Reactions” – click here.

I plan to post more on here as time goes on.  I hope at least this first post gives you a better understanding of what metronidazole toxicity is, and maybe helps to relieve some of your anxiety in at least knowing you are not alone in your struggle.

Feel better!  My heart goes out to you!