TABLE 5

Profile of other antiarrhythmic drugs at human H3 histamine receptors

Drug	Class	Mechanism	pK_i	Inhibition
				%
Disopyramide	IA	Na⁺ blocker	–	20
Procainamide	IA	Na⁺ blocker	–	52
Quinidine	IA	Na⁺ blocker	–	63
Phenytoin	IB	Na⁺ blocker	–	10
Lidocaine	IB	Na⁺ blocker	–	4
Mexiletine	IB	Na⁺ blocker	–	22
Propafenone	IC	Na⁺ blocker	–	7
Flecainide	IC	Na⁺ blocker	–	3
Atenolol	II	β blocker	–	19
Propranolol	II	β blocker	–	17
Acebutolol	II	β blocker	–	26
Metoprolol	II	β blocker	–	9
Nadolol	II	β blocker	–	20
Sotalol	II/III	β/K⁺ blocker	–	27
Dronedarone	III	K⁺ blocker/other	–	55^{^a}
Verapamil	IV	Ca²⁺ blocker	–	29
Diltiazem	IV	Ca²⁺ blocker	–	17
Mibefradil	IV	Ca²⁺ blocker	–	17

Cellular proliferation assays were run as described in Materials and Methods using the indicated ligand in the presence of fixed concentrations of histamine at human H3 histamine receptor isoform 1. Antagonist percent inhibition is normalized to the percent inhibition of thioperamide, and represents the percent inhibition at 10 µM, the highest concentration tested. The dash indicates that the inhibition constant could not be estimated.
↵^a Data generated in radioligand binding assays with H3 histamine receptor isoform 1.