12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The mechanism of action of ADDYI in the treatment of premenopausal women with hypoactive sexual desire disorder is not known. 12.2 Pharmacodynamics Receptor Binding: In vitro, flibanserin demonstrated high affinity for the following serotonin (5-hydroxytryptamine or 5-HT) receptors: agonist activity at 5-HT1A and antagonist activity at 5-HT2A. Flibanserin also has moderate antagonist activities at the 5-HT2B, 5-HT2C, and dopamine D4 receptors. Alcohol Interaction See Clinical Trials Experience (6.1) Cardiac Electrophysiology The effect of ADDYI on the QT interval was evaluated in a randomized, double-blind, placebo- and active- (single dose moxifloxacin) controlled crossover study in 56 healthy men and women. Subjects in the ADDYI groups received either 50 mg twice a day (equivalent to the daily recommended dosage) or 100 mg three times a day (3 times the daily recommended dosage) administered for 5 days. The time frame for electrocardiogram (ECG) measurements covered maximum plasma concentrations of flibanserin and relevant metabolites. In this study, ADDYI did not prolong the QT interval to any clinically relevant extent. The mean increase in heart rate associated with the 100 mg three times a day dose of ADDYI compared to placebo ranged from 1.7 to 3.2 beats per minute. 12.3 Pharmacokinetics Flibanserin showed dose-proportional pharmacokinetics for Cmax after single oral doses of 100 mg to 250 mg (the recommended and 2.5 times the recommended dosage, respectively) in healthy female subjects. Steady state was achieved after 3 days of dosing. The extent of exposure (AUC0-∞) with once-daily dosing of 100 mg of flibanserin was increased 1.4-fold as compared to a single dose. Figure 1 Mean + SD Plasma Flibanserin Concentration-Time Profiles in Healthy Female Subjects Following a Single Oral Dose of 100 mg of Flibanserin (Linear Scale) Reference ID: 4865026