Treatment with cimetidine in patients with primary hyperparathyroidism.

Treatment with cimetidine (1000 mg daily in four divided doses) was given for 3--30 weeks to 10 patients with primary hyperparathyroidism (HPT). All patients had hypercalcaemia and raised serum concentrations of parathyroid hormone (PTH). During treatment no consistent effects were noted on neither serum calcium or PTH and normalization did not occur in any case. Hypergastrinaemia was demonstrated in 6 patients and was also unaffected by therapy while in the 4 patients with normal pre-treatment gastrin values a slight increase was seen. This study does not support the view that cimetidine can be of use for the treatment of primary HPT.