Benadryl, Histamines, Mast cells and Microbiome

A reader who has been very very limited in what they can eat due to histamine response — so limited that a good day is just 500 calories. She has stated taking benadryl once a day with major improvement.

She started taking it on the suggestion of a physician when she shared with the physician that she may have a mast cell dysfunction. I must emphasis, that she was careful to ‘share a suspicion‘ — informing a physician of your self-diagnosis often leads to labelling by medical professional and poor cooperation.

Benadryl is diphenhydramine. It is also known as  Benadryl, Banophen, Diphenhist, Wal-Dryl, Nytol, Unisom, ZzzQuil, Diphen, Benadryl Allergy, Aller-G-Time, and more

Why Benadryl and not some arbitrary antihistamine?

“Diphenhydramine is a sedating peripheral H1 receptor antagonist. It is used for symptomatic relief of allergic symptoms caused by histamine released in response to allergens.”[eMedicine]  H1 receptor antagonist is the fancy way of saying H1-Blocker.

As with most things biological, there are multiple paths to a reaction. In some cases a H2 blocker is a better choice. [eMedicine] lists these as other H1 blockers and sedating (quieting the release of histamines):

There are other H1 blockers but they are not poor sedating or selective.  These include:

In short, all antihistamines are not the same in how they are acting. Finding the right one if you are dealing with histamine and mast cell issues is essential.

But Wait! Let us examine the difference in Microbiome impact!

I tend to be a firm believer that some medicines and drugs also owe their effectiveness to changes of the microbiome they cause.These changes alter metabolites/chemicals the the microbiome produces and the body reacts to. Unfortunately, information on the expensive diamine oxidase (DAO) that is used also, is not available.

In time, I have a page to allow readers to do this themselves on my http://microbiomeprescription.azurewebsites.net/ site – that is, examine microbiome impact when there are multiple candidate drugs to treat an issue.

Table below in Excel: Antihistamines

  • -1 : decreases
  • 1 : increases
  • 0 : no impact
tax_rank tax_name Hydroxyzine_hydrochloride Diphenhydramine Cyproheptadine Loratadine Desloratadine Fexofenadine Cetirizine
family Bacteroidaceae -1 -1 -1 -1 -1 -1 -1
family Bifidobacteriaceae -1 -1 -1 0 -1 -1 -1
family Clostridiaceae -1 -1 -1 -1 -1 -1 -1
family Coriobacteriaceae -1 -1 -1 -1 -1 -1 -1
family Desulfovibrionaceae -1 -1 -1 -1 -1 -1 -1
family Enterobacteriaceae -1 -1 -1 -1 -1 -1 -1
family Eubacteriaceae -1 -1 -1 0 -1 -1 -1
family Fusobacteriaceae -1 -1 -1 -1 -1 -1 -1
family Lachnospiraceae -1 -1 -1 -1 -1 -1 -1
family Peptostreptococcaceae -1 -1 -1 -1 -1 -1 -1
family Porphyromonadaceae -1 -1 -1 -1 -1 -1 -1
family Prevotellaceae -1 -1 -1 -1 -1 -1 -1
family Ruminococcaceae -1 -1 -1 -1 -1 -1 -1
family Streptococcaceae -1 -1 -1 -1 -1 -1 -1
family Veillonellaceae -1 -1 -1 -1 -1 -1 -1
family Verrucomicrobiaceae -1 -1 -1 -1 -1 -1 -1
genus Akkermansia -1 -1 -1 -1 -1 -1 -1
genus Bacteroides -1 -1 -1 -1 -1 -1 -1
genus Bifidobacterium -1 -1 -1 0 -1 -1 -1
genus Bilophila -1 -1 -1 -1 -1 -1 -1
genus Blautia -1 -1 -1 0 -1 -1 -1
genus Clostridium -1 -1 -1 -1 -1 -1 -1
genus Collinsella -1 -1 -1 0 -1 -1 -1
genus Coprococcus -1 -1 -1 0 -1 -1 -1
genus Dorea -1 -1 -1 0 -1 -1 -1
genus Eggerthella -1 -1 -1 -1 -1 -1 -1
genus Escherichia -1 -1 -1 -1 -1 -1 -1
genus Eubacterium -1 -1 -1 0 -1 -1 -1
genus Fusobacterium -1 -1 -1 -1 -1 -1 -1
genus Odoribacter -1 -1 -1 -1 -1 -1 -1
genus Parabacteroides -1 -1 -1 -1 -1 -1 -1
genus Peptoclostridium -1 -1 -1 -1 -1 -1 -1
genus Prevotella -1 -1 -1 -1 -1 -1 -1
genus Roseburia -1 -1 -1 -1 -1 -1 -1
genus Ruminococcus -1 -1 -1 -1 -1 -1 -1
genus Streptococcus -1 -1 -1 -1 -1 -1 -1
genus Veillonella -1 -1 -1 -1 -1 -1 -1
species Akkermansia muciniphila -1 -1 -1 -1 -1 -1 -1
species Bacteroides caccae -1 -1 -1 -1 -1 -1 -1
species Bacteroides fragilis -1 -1 -1 -1 -1 -1 -1
species Bacteroides ovatus -1 -1 -1 0 -1 -1 -1
species Bacteroides thetaiotaomicron -1 -1 -1 -1 -1 -1 -1
species Bacteroides uniformis -1 -1 0 -1 -1 -1 -1
species Bacteroides vulgatus -1 -1 -1 -1 -1 -1 -1
species Bacteroides xylanisolvens -1 -1 -1 -1 -1 -1 -1
species Bifidobacterium adolescentis -1 -1 -1 0 -1 -1 -1
species Bifidobacterium longum -1 -1 -1 0 -1 -1 -1
species Bilophila wadsworthia -1 -1 -1 -1 -1 -1 -1
species Collinsella aerofaciens -1 -1 -1 0 -1 -1 -1
species Dorea formicigenerans -1 -1 -1 0 -1 -1 -1
species Eggerthella lenta -1 -1 -1 -1 -1 -1 -1
species Escherichia coli -1 -1 -1 -1 -1 -1 -1
species Fusobacterium nucleatum -1 -1 -1 -1 -1 -1 -1
species Lactobacillus paracasei -1 -1 -1 0 -1 -1 -1
species Odoribacter splanchnicus -1 -1 -1 -1 -1 -1 -1
species Parabacteroides distasonis -1 -1 -1 -1 -1 -1 -1
species Parabacteroides merdae -1 -1 -1 -1 -1 -1 -1
species Peptoclostridium difficile -1 -1 -1 -1 -1 -1 -1
species Roseburia hominis -1 -1 -1 -1 -1 -1 -1
species Roseburia intestinalis -1 -1 -1 0 -1 -1 -1
species Streptococcus parasanguinis -1 -1 -1 -1 -1 -1 -1
species Streptococcus salivarius -1 -1 -1 -1 -1 -1 -1
species Veillonella parvula -1 -1 -1 -1 -1 -1 -1
species_group Lactobacillus casei group -1 -1 -1 0 -1 -1 -1

Bottom Line

I hope this post will educate people that “all antihistamines are not the same” – both in terms of known mechanism as well as impact on the microbiome.

I am hoping to have a page done by next weekend that will allow the impact of various medications and drugs (as far as is known and published) on the microbiome.

Addendum

The reader is also taking the following in addition to help with  the suspected mast cell issues:

This is an education post to facilitate discussing this approach with your medical professionals. It is not medical advice for the treatment of any medical condition. Always consult with your medical professional before doing any  changes of diet, supplements or activity. Some items cites may interfere with prescription medicines.