PsychoTropical Research - Monoamine oxidase inhibitors, Dietary Tyramine and Drug Interactions

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Monoamine oxidase inhibitors

Monoamine Oxidase Inhibitors, Dietary Tyramine and Drug Interactions

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Document Summary

Key Facts

  • For those who already follow healthy eating (and drinking) amounts and patterns a low tyramine diet involves almost no changes at all.
  • Only rotten foods, or those prepared using 'fermenting' techniques have high tyramine.
  • The possible high blood pressure reaction is proportional to the amount of the tyramine-containing food eaten.
  • There is no food or drink that is so strong (i.e. high in tyramine) that a small amount (i.e. 100 grams or less) is likely to be risky.
  • However some specialised aged Belgian-type beers (Lambic) do have high tyramine, with some having 50 mg/L, and higher. Since they may be drunk on an empty stomach they could be risky.
  • If a reaction ever did occur, and you attend hospital when you get symptoms, the chance of coming to harm is very remote.
  • The symptoms of a reaction are: a thumping forceful heartbeat (usually a slower pulse rate), paleness (pallor), rapid onset severe headache, tightness in the chest. Pulse may drop as low as 40 beats per minute.
  • The risk of harm from blood pressure reactions with foods and MAOIs has previously been greatly exaggerated.
  • Remember to check compatibility of any medications you get, including over-the-counter (non-Doctor scripts) drugs.

General Summary

Interactions between monoamine oxidase inhibitors and other drugs are now understood much more clearly than in the past. These interactions are not as widespread or as difficult to deal with as many people think, and as many texts indicate. In my opinion, such problems with MAOIs are less than with the SSRIs, especially fluoxetine, which has multiple potentially problematic interactions. However, it is relevant to appreciate that many standard texts do contain incorrect information that can cause confusion. The references and details herein may help to clarify these issues.

There is now more quality data on the tyramine levels in foods, and how much tyramine is likely to constitute a problem. Some previous opinions and advice have been based on old data and have over-extrapolated from minimal information. This paper surveys more original data on tyramine than any paper previously published.

All levels are given as mg of tyramine per kilogram or litre: so if you live in a non-metric area, then get smart and think metric: it is unhelpful and confusing to work in standard servings/standard drinks or oz./pints.

Although a small proportion of people may get a significant blood pressure increases with only 10 mg of tyramine a majoriy of people need to have 50 mg or more (in a meal) to get a serious blood pressure increase (i.e. 60 mm Hg or more). For a detailed analysis of the evidence relating to tyramine dose and blood pressure see {Gillman, 2009 #10056} and www.psychotropical.com. So, it is easy to work out how much tyramine is in 100 grams of any of these foods. Learn what 100 grams looks like, and what sensible food portion sizes are: if you eat 1 kg beef steaks, or half a kilo of cheese, chocolate etc. then you will need to adjust to avoid trouble (and to become healthy). Some people will need to consult a dietician for explanations of how to eat sensibly. Also see website information like http://www.win.niddk.nih.gov/publications/PDFs/justenough.pdf

For those who already follow healthy eating amounts and patterns the low tyramine diet involves almost no changes at all. This is because healthy amounts of cheese are around what is safe tyramine-wise: i.e. 100 grams of cheese in a meal is a very large portion, and very few cheeses contain more than 25 mg of tyramine in 100 grams (i.e. 250 mg/kg). So a typical 50 gram portion (12.5 mg tyramine) is very unlikely to cause a blood pressure reaction.

It is important to realise that even if excessive tyramine is taken, serious consequences are most unlikely providing appropriate action is taken. That will usually mean monitoring blood pressure for a few hours and having medication to lower it (in hospital) if it goes over about 180 - 200 mm Hg.

Most countries have Drug information services that can answer questions and such advice should be sought by Doctors or patients when needed. Such telephone numbers can be found via the web, local hospitals, or telephone company inquiry services.

Storage of foods below 5°C is a crucial factor, and some domestic fridges fail the test. It is vital to check your fridge temperature with an accurate thermometer.

Document pages and headings.

Monoamine Oxidase Inhibitors, Dietary Tyramine and Drug Interactions 2

Summary 2
Key Facts 2
General Summary 2

Introduction 3

Mechanism of Tyramine Formation 4

Amino Acids 4

Tyramine in foods and beverages 5

What are the symptoms of a reaction? 6
First, the tyramine champions 6
Milk Products 7
Milk and yoghurt 7
Cheeses 7
Mature cheeses 7
Non-matured cheeses 8
Fermented Sauces - Vegetable 8
Marmite 8
Soy sauce, Miso and Sufu etc 8
Fermented Sauces - Animal 9
Fish Sauces 9

Meat and Fish Products 10

Meat 10
Fresh Meats 10
Dry cured Ham 10
Fermented Sausages 11
Preparations of stock cubes, powders, bouillon, etc 11
Fish 11
Fresh Fish 11
Smoked Fish 12
Dried Fish 12
Canned Fish 12
Fish Sauces 12
Malaysian "budu" and "cincalok" 12

Vegetables 12

L-DOPA 13
Miscellaneous 13
Chocolate 13

Wine and beer 14

Wine 14
Vinegars 15
Beers 15
Other non-serious, non-dangerous interactions 14

MAOIs: Interactions with other drugs 16

Risky analgesics 17
Antidepressant drugs 17
Fluoxetine 17
Ceasing treatment 18
Medical treatment of high BP 18

Acknowledgements 18