 - Therapy within 21 days before day 0 with systemic glucocorticoids, lithium, tricyclic antidepressants with the exception of amitriptyline and nortryptiline, thioridazine, haloperidol, flecainide or other drugs with a narrow therapeutic index that are primarily metabolized by hepatic cytochrome P450 CYP 2D6, drugs that affect renal tubular calcium handling eg, thiazide or loop diuretics, or calcitonin 