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

Vitamin D is essential for bone health and immune function, particularly 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. 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. 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. 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. 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. 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. 4.03% of prescriptions were off-label, including adult-only or inappropriate formulations for neonates and infants under one year of age. Several prescriptions contained excipients of mandatory declaration, especially harmful for neonates and infants, such as ethanol and sucrose. Findings support the need to strengthen pediatric-specific prescribing practices, particularly through improved surveillance of off-label use in primary care.