Failure of cimetidine to reduce postoperative hypocalcemia in patients with primary hyperparathyroidism undergoing...

Although use of histamine H2 antagonists for chronic treatment of primary hyperparathyroidism (PHP) is ineffective, pretreatment with cimetidine has been reported to reduce the incidence of postoperative hypocalcemia in patients with PHP undergoing neck exploratory operation. The current investigation was conducted to determine the validity of this assertion.

In a randomized, double-blind, placebo-controlled trial, 20 patients with PHP were treated with either cimetidine or placebo for 10 to 14 days before neck exploratory operation. Clinical outcome and biochemical indexes before and after drug treatment in both groups were compared.

Cimetidine treatment resulted in a modest increase in preoperative parathyroid hormone level but did not affect any other parameter, including serum calcium level or renal tubular reabsorption of phosphate. Intraoperative time was similar in both groups. Mean postoperative calcium nadir was identical regardless of therapy (8.3 mg/dl), and seven (70%) patients from each group had at least one serum calcium measurement less than 8.5 mg/dl.

Cimetidine treatment before neck exploratory operation for PHP does not diminish the frequency or severity of postoperative hypocalcemia.