Patients with
primary hyperparathyroidism (pHPT) are sometimes treated with
bisphosphonates (BPs) as an alternative to surgery despite sparse documentation of the efficacy in this disorder. It is therefore of interest to study the biochemical effects from BPs in patients with pHPT. A series of 21 pHPT patients with serum
calcium levels > 2.8 mmol/L were included. One month before surgery the patients underwent
intravenous infusions of 30 to 40 mg
pamidronate. Study parameters were total and ionized serum
calcium, intact
parathormone (PTH),
alkaline phosphatase (ALP) and
isoenzymes,
creatinine,
osteocalcin, 25-OH
vitamin D(3), 1,25-OH(2 )vitamin D(3), urine
calcium/
creatinine, and osmolality. Registration of
hypercalcemia-related symptoms were done by questionnaire. After
pamidronate there was a temporary reduction in serum
calcium with a nadir at 6 to 10 days. Normalization of serum
calcium was achieved only by surgery. Intact PTH rose after
pamidronate, with a maximum on day 6. Urinary
calcium excretion was reduced after both
pamidronate and surgery. ALP was reduced 30 days after
pamidronate and also after surgery. Serum
osteocalcin was not influenced by
pamidronate. No statistically significant differences in symptoms were reported
after treatment. In conclusion, there was a short, limited
calcium-lowering effect from
pamidronate in pHPT patients and a transient increase in PTH corresponding to the reduced
calcium concentration. An obvious change in bone markers was found only after surgery. Treatment with BPs should not be considered an alternative to surgery, which is still the only method to cure patients with pHPT.