A method for delivering a therapeutic agent to a subject from a transdermal delivery system is described, where the therapeutic agent (i) has a half-life in the blood when delivered orally of greater than about 48 hours and (ii) is for the treatment of a chronic condition. The transdermal delivery system achieves transdermal delivery of the therapeutic agent that is bioequivalent to administration of the therapeutic agent orally, wherein bioequivalency is established by (a) a 90% confidence interval of the relative mean Cmax and AUC of the therapeutic agent administered from the transdermal delivery system and via oral delivery between 0.70 and 1.43 or between 0.80 and 1.25, or (b) a 90% confidence interval of the geometric mean ratios for AUC and Cmax of the therapeutic agent administered from the transdermal delivery system and via oral delivery between 0.70 and 1.43 or between 0.80 and 1.25.
