B52 (medical treatment)

A B52 is an intramuscular injection containing three medications: diphenhydramine, haloperidol, and lorazepam. The B stands for Benadryl, the 5 stands for 5 milligrams of haloperidol, and the 2 stands for 2 milligrams of lorazepam. This injection is used to treat agitation. Haloperidol is included because it blocks dopamine receptors, which may relieve agitation. Lorazepam is included because it enhances GABA inhibitory action to relieve anxiety and cause sedation. Diphenhydramine is included upon the rationale that it provides sedation and reduces the risk of extrapyramidal symptoms (EPS), such as dystonia, from haloperidol.