Low-dose lactose in drugs neither increases breath hydrogen excretion nor causes gastrointestinal symptoms

Background Despite the reported tolerance to a low dose of lactose, many lactose malabsorbers follow a rigorous lactose-free diet also avoiding lactose-containing drugs. Up to now, only a few case reports have described the onset of gastrointestinal symptoms in lactose malabsorbers following the ingestion of these drugs. It has been suggested that capsules/tablets contain no more than 400 mg of lactose. Aim To evaluate breath H-2 excretion and intolerance symptoms after ingestion of a capsule containing 400 mg of lactose or placebo through a randomized, cross-over, double-blind, controlled study. Methods Seventy-seven lactose maldigesters with intolerance underwent two H-2 breath tests with both 400 mg of lactose and 400 mg of placebo. Gastrointestinal symptoms occurring in the 8 h following the ingestion of different substrates were evaluated by a visual-analogue scale. Results Ingestion of 400 mg of lactose did not cause a significant difference in breath H-2 excretion or in the severity of gastrointestinal symptoms compared to placebo. Conclusion In patients with lactase deficiency, drugs containing 400 mg of lactose or less can be used safely.