Abstract
Objective:
Vitamin D deficiency is prevalent worldwide and is usually treated with oral supplementation. Bioavailability of vitamin D may differ among individuals due to variable absorption and metabolism in the body.
Methods:
A 66-year-old woman presented for evaluation of low 25-hydroxyvitamin D (25[OH]D) level. She had no known prior history of gastric or intestinal surgeries or malabsorptive conditions. She had previously been treated with oral vitamin D3 at 2,000 IU daily with poor response. She was then treated with oral vitamin D2 at 50,000 IU weekly, with persistently low 25(OH)D level at 14 ng/mL after 8 weeks of treatment.
Results:
Celiac screen was negative and duodenal biopsy was normal. Due to demonstration of poor oral absorption, she was prescribed vitamin D2 at 50,000 IU sublingually for 8 weeks and then changed to over-the-counter vitamin D3 drops sublingually (1,000 IU/drop) at 4,000 IU twice daily due to suboptimal response with vitamin D2. 25(OH)D level improved gradually to 28 ng/mL after 12 weeks on this regimen and was at 37 ng/mL at 1 year.
Conclusion:
Sublingual vitamin D3 may be an effective alternative mode of vitamin D supplementation in patients who demonstrate poor oral vitamin D absorption despite adequate supplementation for various reasons.
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