Which conditions impair absorption of levothyroxine?

Which conditions impair absorption of levothyroxine?

• A. Atrophic gastritis, chronic PPI use, and Helicobacter pylori infection
• B. Hyperthyroidism
• C. Celiac disease only
• D. Iron deficiency alone

Answer: (A)

Levothyroxine absorption depends on dissolving the tablet in the stomach (which requires some gastric acidity) and being absorbed in the proximal small intestine. Conditions that reduce acid or damage the gastric mucosa impair this process. Atrophic gastritis decreases acid production, chronic PPI use raises gastric pH, and Helicobacter pylori infection causes gastritis that disrupts the stomach environment needed for efficient dissolution and absorption. Together, these factors commonly blunt levothyroxine absorption and often necessitate dose adjustments or altered administration timing. Hyperthyroidism itself doesn’t directly impair absorption, and while celiac disease can affect absorption, the combination listed is the best-supported set of factors, with iron deficiency by itself not a primary cause.

Levothyroxine absorption depends on dissolving the tablet in the stomach (which requires some gastric acidity) and being absorbed in the proximal small intestine. Conditions that reduce acid or damage the gastric mucosa impair this process. Atrophic gastritis decreases acid production, chronic PPI use raises gastric pH, and Helicobacter pylori infection causes gastritis that disrupts the stomach environment needed for efficient dissolution and absorption. Together, these factors commonly blunt levothyroxine absorption and often necessitate dose adjustments or altered administration timing. Hyperthyroidism itself doesn’t directly impair absorption, and while celiac disease can affect absorption, the combination listed is the best-supported set of factors, with iron deficiency by itself not a primary cause.