Flagyl and Fungi: A Bad Combination?

Flagyl and Fungi: A Bad Combination?

Flagyl is a standard prescribed antibiotic that is used for gram-positive infections including C. difficle and some parasitical infections. There are many different known side effects associated with the medication. These side effects range from the common gastrointestinal upset related to antibiotics to long-term neuropathy and immune system depression. Also, Flagyl is a recognized human carcinogen. Flagyl does, however, have its uses as medication, but its side effects should be more widely known. One of the lesser known side effects of the antibiotic is its possible aldehyde breakdown enzyme down-regulation which increases mold sensitivity. 1

What Are Aldehyde Breakdown Enzymes and Why Do They Matter?

Aldehyde oxidase and aldehyde dehydrogenase are produced by the body to breakdown aldehydes. Aldehydes are many different compounds, including formaldehyde and acetaldehyde. We encounter many different aldehydes throughout our daily life, and differ in their toxicity. 2

Alcohol, for example, is a frequent human exposure to aldehydes that our body needs to process correctly. If it is not able to simple alcohol consumption easily becomes deadly. 3

Consumption of alcohol requires ample amounts of aldehyde oxidase and aldehyde dehydrogenase to convert acetaldehydes produced from ethanol detoxification by the liver into carboxylic acids that can be used by the body. Without theses enzymes, alcohol consumption becomes quite toxic. The medication disulfiram was developed to help treat alcoholism by depleting alcohol and aldehyde detoxification enzymes (mainly ALDH1A1 and ALDH2 somewhat.) When a person consumes alcohol on the drug they develop symptoms similar to mold sensitivity, headaches, brain fog, visual disturbances, elevated heart rate, face flushing, allergic reactions, digestive issues, and shortness of breath. If enough alcohol is consumed the symptoms intensify from a severe hangover to coma and eventually death from untreated aldehyde poisoning. 4 5

Some people have gene mutations sadly that cause the body to produce less of these enzymes or none at all. ALDH2 is one of these genes and is tested if you get a 23 and Me test. Mold and yeast also produce a lot of aldehydes that require these enzymes to help us detoxify them. 6

Does Flagyl Increase Mold Sensitivity?

Flagyl like the medication disulfiram may reduce the body’s ability to produce aldehyde detoxification enzymes. The inhibition of these enzymes is the reason why alcohol is strongly discouraged in people who are taking Flagyl for infections. The same can be said for individuals who have mold sensitivity issues, yeast overgrowth, or live in moldy environments. 7 8 9

Flagyl supposedly inhibits the production of aldehyde detoxification enzymes within our cells and affects our mitochondria and liver function. It is possible that if you needed to take Flagyl and suffer from fungi issues, molybdenum may help increase enzyme production or at the bare minimum help you maintain proper levels of the mineral when you stop the medication so that proper enzyme levels can be up-regulated by the body. The body uses molybdenum to produce aldehyde detoxification enzymes. 10 11 12

There are however a few studies that do cast doubt in Flagyl causing a reduction of aldehyde detoxification enzymes in people who have proper enzyme levels or people that do not have genetic predispositions to lower enzyme potential. One study indicates that the side effects from Flagyl are not from inhibiting aldehyde detoxification enzymes but instead are from the medication producing serotonin syndrome in some people. Another study indicates that the side effects of Flagyl that mimic aldehyde detoxification issues maybe from the microbiome shift caused by the antibiotic. 13 14 15

So it would be my recommendation as well that if the serotonin increasing mechanisms of Flagyl are correct that people taking SSRI’s, 5-HTP, or anything that increases serotonin to talk with their doctor and use caution when using Flagyl.

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