Foods You Should Avoid While Taking Isoniazid

Isoniazid is a medication used to treat active and latent tuberculosis. I was prescribed it as a prophylactic against latent tuberculosis. Having been through nursing school, I picked up my textbooks and read up on Isoniazid to see what potential food interactions could occur while on this medication. This article will list the major foods you should avoid while taking Isoniazid.


Good thing I was never much of a beer, wine, and spirits kinda gal. One of the major adverse effects of taking Isoniazid is hepatitis. Unfortunately, alcohol is very damaging to the liver, especially when consumed in high amounts. So to prevent any potential liver troubles, anyone taking Isoniazid must avoid alcohol consumption. This warning is especially dire for people who have or have had liver problems or hepatitis. And the chances of developing liver problems increase with age.

High tyramine foods (or I ate his liver with some fava beans and a nice chianti!)

These immortal words spoken by cinematic villain Hannibal Lecter are no coincidence. It turns out they contain high levels of tyramine and are found in foods you should avoid while taking Isoniazid. Tyramine is a chemical substance that forms when the protein tyrosine breaks down. Consuming high levels of tyramine while on Isoniazid may cause dangerously high blood pressure. This chemical is most prominent in aged cheeses, wines and beers (even some non-alcoholic ones), and cured or pickled meats. For a more complete list of high tyramine foods, click here. Certain foods like chocolate and caffeinated beverages have lower amounts of tyramine and can be consumed, but in limited quantities.

Foods with histamine

While foods high in tyramine may cause blood pressure to rise to dangerous levels, foods high in histamine do the opposite. Histamine is the chemical naturally released by the body in response to allergies. It is also found in many of the foods you should avoid while taking Isoniazid. High histamine foods can cause low blood pressure and headaches for someone taking this medication. For a list of high histamine foods, click here. You’ll notice some of the same foods high in histamine are also high in tyramine like wine, beer, cured meats, and aged cheeses.

What the heck can I eat???

Needless to say when I saw a list of the foods to avoid while taking Isoniazid, I almost fell off my chair. I spoke with my pharmacist about these potential food interactions and was advised to limit many of these foods rather than not eat them again for 6 months. Speak with your health care provider about which foods are safe in small amounts and which ones you should avoid entirely. What I have done is this:

If I can live without it, I eliminate it.

If I love it, I limit daily and weekly intake and keep a food diary

If I have a question, I call my pharmacist or doctor

If I go out to dinner, I carry a list of these foods and my food diary

Sources:, Low Tyramine Diet, 2011, Isoniazid, February 2012

Personal experience

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