Astemizole
Astemizole (marketed under the brand name Hismanal, developmental code R43512) was a second-generation antihistamine drug that has a long duration of action. Astemizole was discovered by Janssen Pharmaceutica in 1977. It has been withdrawn from the market in most countries because of rare but potentially fatal side effects (QTc interval prolongation and related arrhythmias due to hERG channel blockade).
Histamine dihydrochloride
It is also a FDA-approved active ingredient for topical analgesic use and is available in such products as GOLDEN CREME and Australian Dream Cream, which are used for the temporary relief of minor aches and pains of muscles and joints associated with arthritis, simple backache, bruises, sprains, and strains.
Histamine dihydrochloride is administered in conjunction with low doses of the immune-activating cytokine interleukin-2 (IL-2) in the post-remission phase of AML, i.e. when patients have completed the initial chemotherapy. This combination has been reported to significantly reduce the risk of relapse in AML. The effect is particularly pronounced in patients in their first remission who are below the age of 60.