Osteoporosis occurs when loss of bone tissue exceeds the body's ability to make new bone cells. Bones become brittle and liable to fracture under even mild stress. Exercise and vitamin D and calcium supplements can help to prevent or slow osteoporosis. Although there is no cure, several types of drugs can slow the loss of bone tissue. In contrast, the drug teriparatide, given by daily injection, treats osteoporosis by helping the body to produce new bone cells.
Options
Most doctors prescribe a class of drugs called bisphosphonates as the first line of defense in osteoporosis, according to the Merck Manual. Taken orally, these drugs effectively stop the loss of bone cells. However, many people cannot tolerate them because of severe side effects, including problems with the stomach and esophagus, says the Mayo Clinic.
For people who cannot tolerate bisphosponates, one alternative is a daily injection with a different class of drug called teriparatide, which mimics the body's parathyroid hormone.
Action
The parathyroid glands lie behind the thyroid glands in the neck, controlling the levels of calcium in the body. Teriparatide is a synthetic form of parathyroid hormone called PTH 1-34. Unlike other drugs for osteoporosis that slow the rate of bone loss, teriparatide stimulates the production of new bone cells. According to the teriparatide drug monograph, teriparatide helps the intestines to absorb calcium, and helps the kidneys to reabsorb calcium that would otherwise be excreted.
Use
Doctors normally prescribe teriparatide for people with a high risk of fracture from osteoporosis, including men and women past the age of menopause, according to the Mayo Clinic. The Merck Manual adds that doctors reserve teriparatide treatment for patients who fail to stabilize with other treatments. The drug works when injected subcutaneously, just under the skin of the thigh or abdomen, so the patient can perform the injections at home. The patient injects 20 micrograms of drug once per day using a disposable pen-like device.
Effectiveness
According to the Merck Manual, daily injection with teriparatide for 20 months increased patients' bone mass and reduced the number of fractures they suffered. The drug monograph claims that teriparatide increases bone mineral density and strength.
Side Effects
Because doctors do not know the potential long-term side effects of using teriparatide, for now, patients only use it for a maximum of two years, says the Mayo Clinic. The greatest worry is that the patient might develop osteosarcoma, an aggressive form of bone cancer. Other side effects include nausea, weakness and low blood pressure. The teriparatide drug monograph recommends that patients sit or lie down after administering their first injection because of the risk of a sharp drop in blood pressure.
