[Severe megaloblastic anaemia by triamterene in a patient with alcoholic liver cirrhosis (author's transl)].

Mucosal ulceration and severe bone-marrow insufficiency with marked megaloblastic transformation occurred during treatment with triamterene in a patient with decompensated alcoholic liver cirrhosis and malnutrition. When the triamterene-containing preparation was stopped and folinic acid administered the haematological picture improved, but the patient died, with signs of hepatocellular insufficiency, of gastro-intestinal bleeding. The serum folic-acid level was markedly reduced due to the chronic malnutrition, while the vitamin B12 level was within normal limits. This observation indicates that when the pool of folic-acid coenzymes is reduced, triamterene can cause megaloblastic anaemia due to its folic-acid antagonism. Triamterene should, therefore, be given to patients with borderline folic-acid reservoirs, chronic alcoholism or during pregnancy, only under careful serial control of the blood picture.