Bone marrow hypoplasia during intensive care: bone marrow culture studies implicating ranitidine in the suppression of haemopoiesis.

Two seriously ill patients with renal failure developed bone marrow hypoplasia and peripheral blood cytopenias during admission to an Intensive Care Unit (ICU). Both patients were being treated with ranitidine and, in both, there was evidence of drug accumulation. Serum from the patient with the highest concentration of ranitidine inhibited granulocyte-macrophage colony growth from normal bone marrow. The addition of ranitidine to cultures of normal bone marrow also produced a concentration-dependent inhibition of colony growth. Ranitidine should be used with caution in patients with renal failure where drug accumulation may seriously impair bone marrow function.