THE CONSULTANT PHARMACIST JUNE 2017 VOL. 32, NO. 6 337 New Perspectives Cholecalciferol (D 3 ) Versus Ergocalciferol (D 2 ) in Older Adults Simona Dereje, Ilan Muradov, Samira Nazzal, Timothy Nguyen Vitamin D is a fat-soluble vitamin that is naturally found in very few food sources. It is produced endogenously from ultraviolet light from the sun striking the skin and then triggering vitamin D synthesis and activation. Vitamin D helps promote calcium absorption in the gut, maintains adequate serum calcium and phosphate levels, promotes bone growth, modulates cell growth, and has many other roles. There have been an increasing number of people, especially in older adults, with vitamin D deiciency. This is in part a result of a reduction of sun exposure as people age, increase in use of sunscreen, and other factors. This article highlights the roles of cholecalciferol (vitamin D 3 ) versus ergocalciferol (vitamin D 2 ) supplementation for practicing pharmacists. KEY WORDS: Cholecalciferol, Ergocalciferol, Older adults, Vitamin D. ABBREVIATIONS: 25-hydroxyvitamin D = 25(OH)D, IOM = Institute of Medicine, Vitamin D 2 = Ergocalciferol, Vitamin D 3 = Cholecalciferol. Consult Pharm 2017;32:337-9. Introduction Vitamin D insuiciency (levels < 29 ng/mL) is highest among older adults and individuals who are institutionalized or hospitalized. 1 According to the Institute of Medicine (IOM), a 25-hydroxyvitamin D [25(OH)D] level less than 20 ng/mL is a vitamin D deiciency, and 21-ng/L to 29 ng/L is vitamin D insuiciency. 2 Vitamin D insuiciency can lead to symptoms that include muscle weakness, unexplained fatigue, bone pain, diiculty thinking clearly, and sot bones that may result in deformities; in many cases it is asymptomatic. 1,2 Furthermore, a level of < 20 ng/ mL constitutes vitamin D deiciency and can ultimately lead to complications such as impaired immune system functioning, rickets, insulin resistance, and brittle bones. 2 hese complications and the broad spectrum of symptoms highlight the importance of getting screened, especially in individuals who are considered high risk (Table 1). hose: • With osteoporosis or malabsorption syndrome • Are obese (> 30 kg/m 2 ) • Have disorders that afect vitamin D and phosphate metabolism, e.g., chronic kidney disease • Are African-American and Hispanics 2,3 he National Health and Nutrition Examination Survey found that more than 40% of the American population were vitamin D deicient (levels < 20 ng/ mL), with the highest rates seen in African-Americans Table 1. Major Causes of Vitamin D Deiciency • Inadequate sunlight exposure • Sunscreen • Nutrient deiciencies • Increased requirement or increased excretion • Natural dark skin tone • Obesity • Fat malabsorption (e.g., inlammatory bowel disease, gastric bypass surgery) • Nephrotic syndrome • Medications (e.g., anticonvulsants, some HIV meds) • Other causes (e.g., older adults) Abbreviation: HIV = Human immunodeiciency virus. Source: References 2, 3.