Pharmacy and Medications

Forteo for osteoporosis

12/12/2005

Question:

I have osteoporosis, and after several years of taking Fosamax, Actonel (and others whose names I cannot recall), my doctor has prescribed Forteo. After considering the risks of taking Forteo, I would appreciate your view of this new drug. Just reading the package information is scary! Thanks

Answer:

Teriparatide (Forteo) is a modified version of a natural hormone, parathyroid hormone (PTH). This hormone helps to regulate the levels of calcium in your blood. In osteoporosis, this action helps strengthen bones and prevent fractures. Teriparatide is given as a subcutaneous (under the skin) injection at a usual dose of 20 micrograms per day.
The effectiveness of teriparatide in osteoporosis has been shown in one large study. It reduced the risks of fractures in the spine and fractures in other parts of the body. Bone mineral density was improved in patients taking teriparatide.
Teriparatide is generally well tolerated. However a number of side effects have been reported. Some of the side effects reported by patients taking teriparatide, include angina (chest pain), dizziness, leg cramps, nausea and hypercalcemia (high calcium levels in the blood). Most of these side effects are temporary, but should be reported to your doctor if they become bothersome or persist.
Teriparatide may also cause orthostatic hypotension, which is dizziness that occurs when changing position, especially from laying or sitting. This effect can be minimized by getting up slowly after sitting or reclining. This side effect is not a cause to discontinue the medication. This adverse effect should decrease in severity with continued use.
Perhaps the most worrisome adverse effect mentioned in the package insert is the development of osteosarcoma, a tumor in the bone. Osteosarcoma was reported in preliminary studies in rats using the equivalent of between 3 and 60 times the normal human daily dose of teraparatide. At the highest dose given in the rat studies, the rate of occurrence of osteosarcoma approached 40-50%. Whether teriparatide increases the risk of osteosarcoma in humans is currently unknown. However, a study in 1600+ patients receiving normal doses none of the patients developed of osteosarcoma in the 18 month study period. Patients that have another bone disorder, children with Paget's disease and patients who have had radiation therapy have a higher risk for developing osteosarcoma than the general population.
Teriparatide is an alternative for patients who have osteoporosis. As with any medication, there are risks to be considered when taking medication. Another factor to consider is the cost of medication. Teriparatide is fairly expensive. In 2004 the drug was roughly ten times more expensive than the medications you have already tried (Fosamax/alendronate and Actonel/risendronate).
When starting any new medication, it is important to weigh the risks of taking the medication against the benefits of taking the medication. If you have concerns about taking teriparatide, discuss them with your doctor or a pharmacist who knows you. Other alternatives do exist, and together, you and your doctor can find the therapy that works best for you. With proper monitoring and awareness of the potential side effects of teriparatide, the medication may be used safely and effectively for osteoporosis
This answer was prepared by Brad Baugh, a PharmD candidate at the University of Cincinnati College of Pharmacy.

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Response by:

Robert James Goetz, PharmD, DABAT
Assistant Professor of Pharmacy Practice
Drug and Poison Information Center
Cincinnati Children’s Hospital Medical Center
University of Cincinnati