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

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.

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.

Seventy-seven lactose maldigesters with intolerance underwent two H2 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.

Ingestion of 400 mg of lactose did not cause a significant difference in breath H2 excretion or in the severity of gastrointestinal symptoms compared to placebo.

In patients with lactase deficiency, drugs containing 400 mg of lactose or less can be used safely.