Neurocardiogenic Vasovagal syncope is more common in younger patients but also should be considered in elderly patients with unexplained syncope. Although the triggering mechanisms are complex and may differ among young and elderly patients, the efferent responses generally can be categorized as cardioinhibitory (pauses of = 3 seconds or heart rate <40 beats per minute for more than 10 seconds), vasodepressor (systolic blood pressure falls by 50 mm Hg or more without symptoms or 30 to 50 mm Hg with symptoms of syncope or presyncope, and the heart rate does not decrease by more than 10%), (more…)

Pharmacodynamics describes the course of action of a drugs and aging at the effector organ level, in terms of duration and magnitude of action, and amplitude of and time to reach the peak action, for both therapeutic and adverse actions. Alterations in the number and affinity of drug receptors, postreceptor signaling processes, biochemical responses, homeostatic mechanisms, and body composition, in addition to higher likelihood of polypharmacy and concurrent pathological processes in older age, make elders more susceptible to adverse drug reactions, drug–drug interactions, or decreased/ increased sensitivity to some drug action. (more…)