Lactose content of gastrointestinal drugs: does it matter?

Abstract

Sirs, I read with interest the paper by Eadala et al.1 reporting the amount of lactose contained in oral medications commonly employed to treat gastrointestinal disorders. While it is certainly important to be aware that lactose is often present in a wide range of drugs in higher amounts than previously suspected, this finding should not be overemphasized. It is well known that most patients with lactose intolerance can ingest up to 10–12 g of lactose without experiencing symptoms.2, 3 Others consider the safety limit to be as low as 5 g.4 Whatever be the truth and allowing that a minority of subjects can be sensitive to even lower doses,5, 6 the amount of daily lactose intake calculated by Eadala et al in the examined medications is bound to be, with a few exceptions (such as lactulose and, possibly, budesonide and loperamide), clinically irrelevant. Moreover, a recent study has provided evidence that ingestion of 400 mg of lactose from oral medications does not cause a significant effect either on breath H2 excretion or on gastrointestinal symptoms.7 On the other hand, patients with irritable bowel syndrome (IBS) often ascribe bloating and diarrhoea to the ingestion of foods and drugs irrespectively of their possible lactose content. Caution should be exercised before concluding that lactose-free medications must be prescribed to patients with IBS or other intestinal disorders. Declaration of personal and funding interest: None.