Participants Healthy male participants will receive escalating doses of levomilnacipran, duloxetine, or placebo every 4-7 days throughout a 14-23 day period. The tyramine pressor procedure will be used to identify the dose at which these medications inhibit norepinephrine reuptake. Serotonin reuptake inhibition will be estimated from whole blood serotonin concentrations. Tyramine testing and blood draws will occur at baseline (prior to medication administration) and 4 days after each dose escalation.