Toxicity of trimethoprim-sulphamethoxazole in patients with megaloblastic haemopoiesis.
Four consecutive patients with megaloblastic anaemia who also received therapy with trimethoprim-sulphamethoxazole all showed poor responses to specific haematinic therapy. This was attributed to trimethoprim, which suppressed reticulocyte responses in three cases and produced a pancytopenia in two and a falling haemoglobin with neutropenia in a third. A fourth patient, with pernicious anaemia, had a satisfactory reticulocyte response but experienced no clinical benefit until after withdrawal of trimethoprim.Trimethoprim seems not to be a safe form of therapy in patients with a megaloblastic process; many of the toxic reactions reported with this drug may be on the basis of an unrecognized megaloblastic form of haemopoiesis.
D000328:Adult; D000368:Aged; D000380:Agranulocytosis / Q000139:chemically induced; D000748:Anemia, Macrocytic / Q000188:drug therapy*; D000752:Anemia, Pernicious / Q000150:complications; D000890:Anti-Infective Agents / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D001792:Blood Platelets; D004906:Erythrocyte Count; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D005493:Folic Acid Antagonists / Q000009:adverse effects*; D005494:Folic Acid Deficiency / Q000150:complications; D006801:Humans; D008875:Middle Aged; D011743:Pyrimidines / Q000009:adverse effects*; D012156:Reticulocytes / Q000187:drug effects; D013420:Sulfamethoxazole / Q000009:adverse effects*; D013762:Tetrahydrofolate Dehydrogenase / Q000097:blood; D014295:Trimethoprim / Q000009:adverse effects; D014805:Vitamin B 12 / Q000627:therapeutic use; D014806:Vitamin B 12 Deficiency / Q000188:drug therapy
D000890:Anti-Infective Agents; D005493:Folic Acid Antagonists; D011743:Pyrimidines; D005492:Folic Acid; D014295:Trimethoprim; D013762:Tetrahydrofolate Dehydrogenase; D013420:Sulfamethoxazole; D014805:Vitamin B 12