my personal edition > osteoporosis > news


  E-Mail this DGDispatch to a colleague

DGDispatch

First Report of Severe Hypocalcaemia During Alendronate Treatment: Presented at AACE

By W. A. Thomasson
Special to DG News

CHICAGO, IL -- May 6, 2002 --Researchers have documented the first known case of hypocalcaemia and hyperparathyroidism associated with alendronate treatment.

Mario Skugor, MD, and colleagues at the Cleveland Clinic Foundation, Ohio, United States, presented the findings here Saturday at the annual meeting of the American Association of Clinical Endocrinologists (AACE).

There have been five reports of hypocalcaemia following treatment with other bisphosphonates; three cases were associated with predisposing risk factors, and the medication was given intravenously in the other two, the researchers noted.

The current case is a 78-year-old woman who had been diagnosed with osteoporosis and was started on alendronate 70 mg/week plus calcium 1,500 mg/day and vitamin D 800 IU/day. After three months of alendronate treatment she was referred to the Cleveland Clinic based on elevated levels -- 98 pg/mL -- of intact parathyroid hormone (iPTH). Calcium and albumin levels were normal, and phosphorus was low normal. On repeat measurement, iPTH had dropped to 65 pg/dL, just above the normal range, but then rebounded to 121 pg/mL a month later. There were no notable changes in other values.

The problem was felt to be the transient hyperparathyroidism that is sometimes seen as a result of alendronate initiation, and the physicians decided to follow her with repeat measurements every two months.

A month later, however, she presented to the emergency room with symptoms of hypocalcaemia and serum calcium levels of 6.8 mg/dL. She was treated with intravenous calcium and alendronate treatment was discontinued.

At the end of month 2, her iPTH had dropped to 21 pg/mL. She was then rechallenged with 35 mg of alendronate per week. After week 2 her iPTH has risen to 64 pg/mL, and by week 4 it was 85 pg/mL. Calcium and phosphorus levels were decreasing, although still within the normal range. Alendronate was then discontinued permanently, with renormalization of values.

The authors concluded that this case may indicate the need for periodic calcium determinations during weekly alendronate therapy. "Calcium measurements are automated," said Dr. Skugor in an interview with Doctor's Guide, "so it's not as though we're embarking on a big expense."

Still, testing everyone might be an overreaction to a single case, even though the problem can be serious when it occurs. "I think we should select the patients," he said, naming a number of conditions associated with poor calcium absorption, increased calcium excretion, or other abnormalities that might place patients at risk. He also noted that the case underscored the need for calcium and vitamin D supplementation in connection with alendronate use, even though in this instance supplementation did not prevent the problem.

E-Mail this DGDispatch to a colleague

To print, use this version