Table 1

Pharmacokinetic parameters and potencies of HERG inhibition of the macrolides

Drug	pK_a	Dose	TotalC_max	PPB	FreeC_max	IC₅₀	IC₅₀ (μM)/FreeC_max (μM)
		mg/day	μg/ml	%	μM
Clarithromycin	8.99	500	2.6	70	1.04	32.9	32
Roxithromycin	N.A.	300	10	80	2.39	36.5	15
Erythromycin	8.88	2000	4.9	80	1.34	72.2	54
Josamycin	N.A.	400	0.3	15	0.31	102.4	332
Erythromycylamine	8.96	500	0.4	20	0.43	273.9	642
Oleandomycin	8.84	500	0.8	51^1-150	0.57	339.6	596

Data were obtained from Periti et al. (1989),Nilsen (1995), and McFarland et al. (1997). Data were also obtained from Physicians' Desk Reference (1999).

PPB, plasma protein binding; N.A., not available.
↵1-150 In-house data.