Researchers at Creighton University have developed a new antihistamine that blocks the H3 histamine receptor. The new drug that blocks H3 is called by its research name – PF-03654746. It’s an exciting discovery because it appears to be the first antihistamine that reduces congestion.
Up until now the only way to reduce nasal congestion was to take an antihistamine/decongestant combination such as Allegra-D or Zyrtec-D. These drugs contain Sudafed, which works, but brings the potential issues of causing insomnia and raising blood pressure. Additionally, taken on a daily basis the body eventually becomes tolerant of its effects and the congestion comes back. Furthermore, because Sudafed can be used to make street drugs it has become closely controlled by the government.
This new antihistamine doesn’t raise blood pressure, cause insomnia or lead to tolerance. It seems to treat congestion by blocking the H3 receptors found in nerves in the nasal membranes. Blocking the H3 on the nasal nerves keeps blood vessels from being engorged and leading to tumescence (i.e. nasal congestion). Clinical trials done with the drug have shown it to be safe and effective. Hopefully, FDA approval will be forthcoming.
(There are currently four known histamine receptors in the human body numbered 1 through 4: H1 blockers are well known and include Benadryl, Allegra, Claritin, Zyrtec and others. H2 blockers are also known and numerous and include Zantac, Pepcid, Tagamet and Axid. H4 blockers are still an early research topic.)