Isoniazid, quinidine, and sulphafurazole absorption in patients with jejunum transposition 15 years earlier.

Gastric surgery has formerly been shown to affect drug absorption. The absorption of oral isoniazid (INH), quinidine, and sulphafurazole (sulfisoxazole) was therefore studied in 19 ulcer patients operated on some 15 years earlier with resection of the ventricle combined with jejunum transposition. Twelve medical inpatients served as controls. The operated patients had all experienced relief of their ulcer symptoms, and there was no evidence of clinical malabsorption. In operated patients the peak serum levels of all three drugs were reached earlier than in controls. At 1 and 6 h the INH serum levels were increased in operated patients, but the sulphafurazole serum levels were at no time different in operated and control patients. As measured by the 24-h urinary excretion, jejunum transposition did not modify the total amounts of INH or sulphafurazole absorbed. In contrast, the quinidine absorption was decreased by about 50% in operated patients, which seems to be the result of increased gastric pH in the operated patients, leading to a poor dissolution and/or precipitation of quinidine in the gastric contents. Obviously, the jejunum transposition per se may not affect the total amounts of drugs absorbed, provided the physiochemical effects resulting from, for example, pH changes due to antrectomy and/or vagotomy are taken into account.