Older adult patients comprise the majority of hospitalized patients. Additionally, the frail elder population continues to grow, as people are living well into their 90s and beyond. Adult-Gerontology Acute Care Nurse Practitioners (AG-ACNPs) must constantly be aware of normal physiologic changes, and pharmacokinetics and pharmacodynamics associated with prescribing for this population. A foundational tenet of prescribing in the older adult population is to “start low and go slow”. Avoid inappropriate medications in hospitalized older patients, as they are at greater risk for delirium, which can increase complications, length of stay, and mortality. This chapter helps the AG-ACNP learn the normal physiologic changes associated with aging, the pharmacokinetics in the aging population, tips for prescribing for older hospitalized patients, drugs to avoid with older patients, and causes of falls in the older population.