Vasovagal syncope (VVS) is the most common type of syncope. The mechanism is reflex-mediated triggered by various afferent input to the brain. The event is usually preceded by diaphoresis, warmth, nausea, and pallor, and is followed by fatigue. While several drugs are indicated in the treatment of VVS, to our knowledge, there is no current treatment of an impending syncopal attack. In the present study, the investigators hypothesize that a single administration of sublingual CPC preparation during the prodromal phase aborts tilt-induced syncope or near syncope with SBP less than or equal to 70 mmHg in patients with a history of VVS. Patients with an established diagnosis of typical VVS or near syncope will be randomized to receive CPC or placebo in 1:1 ratio. Drug or placebo will be administered at the onset of prodromes during tilt table testing. In addition to the primary endpoint (syncope or near syncope with SBP less than or equal to 70 mmHg), the investigators will be assessing the effects of the drug on time to event, incidence of asystole (> 3 sec), and fatigue after tilt table testing.
Syncope is defined as transient loss of consciousness associated with inability to maintain postural tone with rapid and spontaneous recovery. The purpose of this study is to assess the effects of sublingual administration of a new medication called CPC on tilt-induced syncope in patients with a history of vasovagal syncope (VVS) or near syncope. 132 participants will be enrolled at the University of Wisconsin - Madison. Each participant will be in the study for 1 day.