Important Notice: Our web hosting provider recently started charging us for additional visits, which was unexpected. In response, we're seeking donations. Depending on the situation, we may explore different monetization options for our Community and Expert Contributors. It's crucial to provide more returns for their expertise and offer more Expert Validated Answers or AI Validated Answers. Learn more about our hosting issue here.

What are H1 and H2?

April 26, 2017H1 H2

0

10 Posted

What are H1 and H2?

1 Answer

0

10 Posted

Mast cells release 3 known types of histamine, H1, H2, H3. It is believed there are also H4 and H5 histamine. Skin has receptors at least for H1 and H2. Airways have receptors for H1, the gastrointestinal (GI) tract has receptors for H2, and the brain is believed to have H3 receptors. The H1 drugs are those commonly thought of as antihistamines, such as Zyrtec, Benadryl, Claritin, Allegra, and Atarax. The H2’s are normally thought of as ulcer medications, but are actually histamine 2 blockers. Zantac, Pepcid, Axid and Tagamet are the most common.