Natpara approved for hormone disorder causing low blood calcium

(HealthDay)—Natpara (parathyroid hormone) has been approved by the U.S. Food and Drug Administration to control low blood calcium among people with hypoparathyroidism.

Hypoparathyroidism is a rare disease that occurs when the body doesn't secrete enough parathyroid hormone, which regulates blood levels of calcium and phosphorus.

Hypoparathyroidism is typically caused by malfunctioning or surgically removed parathyroid glands. The condition affects about 60,000 people in the United States, the FDA said in a news release. Symptoms commonly include numbness, tingling, muscle twitching, cramps, abnormal heart rhythm and seizures. Longer-term complications may include kidney damage, kidney stones and cataracts.

Natpara, a once-daily injection, was evaluated in a clinical study of 124 people. Forty-two percent of those treated with Natpara achieved normal blood calcium levels, the FDA said.

The drug's label includes a boxed warning that bone cancer had been observed in a study of rats given Natpara. However, it's unknown if the drug would cause bone cancer among people, the FDA said.

The most common side effects of Natpara include tingling, pricking and burning of the skin, low blood calcium, headache, high blood calcium and nausea.

Natpara is produced by NPS Pharmaceuticals, based in Bedminster, N.J.