This study will evaluate the safety and tolerability of MK-4618 when coadministered with antihypertensive agents and will evaluate changes in blood pressure following co-administration of MK-4618 with a beta blocker and a vasodilator. The primary hypothesis of the study is that MK-4618 does not result in a clinically meaningful change in systolic blood pressure relative to placebo when co-administered with a beta-blocker or with amlodipine.