Changes in acid-base balance and calcium metabolism after urinary diversion through ileal segments. II. Treatment with nicotinic acid.

Investigations in animals have shown that nicotinic acid, an intestinal cyclic-AMP inhibitor, partially corrects the metabolic changes associated with urinary diversion through intestinal segments. Blood and serum chemistry were studied in patients before and 3 to 5 months after undergoing urinary diversion through ileal segments, both with and without nicotinic acid treatment. It was found that diverted patients had metabolic acidosis, an increased anion gap and increased levels of serum alkaline phosphatase; there were no significant changes in serum PTH and vitamin D levels, calcaemia and phosphoraemia. There was a tendency towards dehydration, hypernatraemia, hyperchloraemia and secondary hyperaldosteronism produced by ileal secretion of a hypotonic fluid. Nicotinic acid 3 g/day significantly reduced the chloraemia but did not correct the metabolic acidosis, although it reduced its severity, since blood pH decreased when treatment was suspended. Nicotinic acid cannot be recommended for routine use in the management of metabolic acidosis after urinary diversion, and patients with a marginal renal reserve should not be considered for trans-intestinal urinary diversion.