Calcium crucial to benefits of osteoporosis drugs

Mar 23 2005

Although an increasing number of people are taking powerful new prescription drugs to treat osteoporosis, chances are the majority of patients are not getting the greatest effect from these medicines because they do not have an adequate calcium and vitamin D intake, according to a paper published in the March 2005 issue of The Journal of Women's Health.

John A. Sunyecz, M.D., president of MenopauseRx, Inc., who co-authored the paper, "Calcium's Role in Osteoporosis Drug Therapy," notes that many people being treated for osteoporosis mistakenly think their calcium and vitamin D intake is no longer important once prescription therapy begins. "People taking osteoporosis medications should remember that they do not contain calcium and have been proven most effective when taken with adequate calcium and vitamin D, usually achieved with the addition of supplements to the daily diet," he explains.

"This paper builds on previous research published last year that shows physicians are not taking the clinical information we know about these drugs and putting it into practice when treating patients. From 1994 to 2003 there was a five-fold increase in prescriptions for bisphosphonates, however during that same time period, the percentage of osteoporosis patients who were treated with calcium supplements decreased by nearly 50 percent."

Dr. Sunyecz also stresses the importance for physicians prescribing osteoporosis drugs to educate their patients about the necessity for calcium supplementation.

"Physicians need to take a more active role by prescribing calcium supplements along with the drugs and informing their patients that these drugs will only be effective if taken properly," he says.

The paper reviewed the clinical trials leading to the Food and Drug Administration (FDA) approval of the osteoporosis drugs, which fall into four categories: bisphosphonates (alendronate/Fosamax, risedronate/Actonel); recombinant human parathyroid hormone (PTH) (teriparatide/Forteo); calcitonin (Miacalcin); and selective estrogen receptor modulators (SERMs) (raloxifene/Evista). The osteoporosis drugs have been proven effective only when taken in conjunction with adequate calcium plus vitamin D.

Dr. Sunyecz observes that many patients he sees in his daily medical practice do not pay attention to achieving the target calcium level until he counsels them on its importance.

"Their assumption is 'I'm on this osteoporosis prescription now, so I no longer need to worry about calcium,'" he reports. "I believe this is occurring partly because the doctors who have prescribed the medication did not emphasize the need for calcium enough, and partly because patients are just jumping to the wrong conclusions."

To help patients understand how osteoporosis drugs work, Dr. Sunyecz explains, "Think of you body as a construction site with your bones as the unfinished frame, osteoporosis drugs as the tools and calcium as the raw material needed to build the structure. If your body doesn't have the raw material, the tools alone may be ineffective in building the structure."

Experts say that adult Americans should be consuming between 1,000 and 1,200 mg of calcium per day, and certain groups like teens, pregnant women and postmenopausal women require even more.

Many people find it difficult to obtain enough calcium through diet alone. In fact, 75 percent of Americans don't get enough calcium through diet. The average woman over 50 has a calcium intake of less than half the amount recommended for postmenopausal women, and people with osteoporosis who routinely have low calcium intakes are more likely to need a calcium supplement to achieve the most effective treatment.

In his recent report on Bone Health and Osteoporosis, the U.S. Surgeon General states that supplements may be helpful for people who don't get enough calcium in their diets. Os-Cal and TUMS, the two calcium supplements doctors recommend most, are excellent choices that require just one or two tablets with breakfast and dinner to meet the recommended amount of calcium.

The selection of a calcium supplement should be determined based on a number of factors, including availability, absorbability and cost. The key is to choose a supplement that will be taken every day.

The two most common sources of calcium in supplements are calcium carbonate and calcium citrate, which are equally well absorbed when taken with food. Calcium carbonate has about twice as much elemental calcium as calcium citrate (40 percent vs. 21 percent). So supplements like TUMS and Os-Cal, which are calcium carbonate, require fewer and smaller tablets to achieve a given dose of elemental calcium. Os-Cal and TUMS also cost less than the leading calcium citrate supplement.

"Since calcium carbonate supplements, such as Os-Cal +D and TUMS, have the highest percentage of elemental calcium, they are considered the most cost-effective form and should be the first choice for most patients," says Dr. Sunyecz.

Dr. Sunyecz also points out that calcium supplements should not be taken at the exact same time as bisphosphonates. Calcium carbonate supplements should be taken with food while bisphosphonates should be taken on an empty stomach, which makes it less likely that patients will take the two together, thus limiting the risk of poor bisphosphonate absorption.

The FDA states that "calcium and vitamin D supplements are an integral part of all treatments for osteoporosis." Using a prescription osteoporosis medication alone may not help very much. Most of the clinical studies submitted for the FDA approval of the osteoporosis drugs required adequate calcium supplementation. In fact, Os-Cal +D was the calcium supplement used in most of the clinical trials for these drugs.

"Although the FDA recommends that consumers use supplements as a part of osteoporosis treatments, the message is often not emphasized by doctors themselves," says Dr. Sunyecz. "It is crucial that doctors advise patients to take calcium supplements regularly every day, and to work with them to make sure they are getting the benefits of the osteoporosis drug treatment."

Dr. Sunyecz also calls to attention the need for stronger guidance on package labeling for osteoporosis drugs and to give stronger guidance regarding calcium supplement recommendations.