Cotrimoxazole and folate metabolism.
Cotrimoxazole 4 tablets daily (1 tablet = trimethoprim 80 mg and sulphamethoxzole 400 mg) was given for a period of six to fourteen days to 13 inpatients, and serum-folate levels were measured before and one day after the course of treatment. The results were compared with those from 8 patients not receiving antibacterial therapy, tested on admission and one week later. Two assay techniques were used, one employing Lactobacillus casei and the other 125I-labelled folate isotope dilution. The microbiological technique showed a significant decline in folic-acid levels in the serum after cotrimoxazole, and this decline was not seen in controls. By contrast, the radioisotope technique showed no significant alteration in serum-folate levels compared with controls. This suggests that cotrimoxazole does not depress true serum-folate and that many low microbiological results obtained during cotrimoxazole therapy reflect interference with the assay organism. There is insufficient evidence to incriminate cotrimoxazole as a significant cause of blood dyscrasias in excess of those which might occur on sulphonamide alone or even with other antibacterials.
D001681:Biological Assay; D004338:Drug Combinations; D005492:Folic Acid / Q000097:blood / Q000378:metabolism*; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes; D007780:Lacticaseibacillus casei; D011865:Radioisotope Dilution Technique; D012141:Respiratory Tract Infections / Q000097:blood / Q000188:drug therapy; D013420:Sulfamethoxazole / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D014295:Trimethoprim / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D014552:Urinary Tract Infections / Q000097:blood / Q000188:drug therapy
D004338:Drug Combinations; D007457:Iodine Radioisotopes; D005492:Folic Acid; D014295:Trimethoprim; D013420:Sulfamethoxazole