Prescription of vitamin D in neonates and infants under one year of age in Spain: An eight-year observational study

in early life. While its supplementation is widely recommended during infancy, data on prescribing patterns in the pediatric population— especially in a primary health care setting—are limited, particularly in Spain. Objective To determine the prevalence and characteristics of vitamin D prescriptions in infants under one year of age in Spain, and to identify potential safety concerns related to off-label use and excipients. Methods We conducted a cross-sectional, observational study using prescription data from January 2013 to December 2020. All prescriptions of medications containing vitamin D (cholecalciferol or calcifediol) for infants aged < 1 year in primary health care were analyzed. Variables included were pharmaceutical form, dosage regimen, age indication, prescription requirement, and the presence of mandatory-declaration excipients. Results A total of 4,829,158 prescriptions were recorded. Cholecalciferol was the most frequently prescribed active ingredient (96.43%). Considering all vitamin D medications, oral solution was the predominant pharmaceutical form (99.43%), and daily administration was the most common dosing regimen (96.51%). Off-label prescriptions accounted for 4.03% of the total, often involving adult-only formulations or pharmaceutical forms unsuitable for infants, such as tablets/capsules and orodispersible tablets. Several medications included excipients with known pediatric safety concerns, such as ethanol, sorbitol, aspartame, and sucrose. Conclusion This large long-term study provides critical insight into vitamin D prescribing practices in primary care for infants in Spain. While most prescriptions aligned with pediatric recommendations, the presence of off-label use and potentially harmful excipients highlights the need for improved regulatory oversight and prescriber awareness. Highlights • Analysis of 4.8 million vitamin D prescriptions in Spanish neonates and infants aged < 1 year. • 96.43% of prescriptions involved cholecalciferol, primarily as an oral solution with daily dosing.