DEAR DR. ROACH: My primary care doctor has prescribed the medication Evenity for my osteoporosis. I have been on Fosamax for about three years, but my recent bone density scan went down slightly in the osteoporosis area. I am very concerned about the black-box warning of heart attacks and strokes since this is a very new drug with very little trials. I am hesitant to start it and am very interested to know your opinion on the safety of this drug.

• C.M.

ANSWER: Alendronate (Fosamax) is a bisphosphonate — the most commonly used initial treatment for osteoporosis based on decades of safety data. When used properly for men and women who are at a high risk of fracture, and when used for an appropriate amount of time (usually three to five years before reassessing), the risks are small. The benefit in preventing a serious fracture outweighs these small risks for most people.

When bisphosphonates like alendronate don’t work in a person who is taking it as prescribed, it’s worth considering whether it might not have been absorbed by the body well or if the person is getting the necessary calcium and vitamin D for the medication to work. They must be taken very carefully as foods and other drugs (even water with a high mineral content) can cause them to be poorly absorbed.

If no reason can be found, then switching to a different class of drugs is reasonable. Romosozumab (Evenity) is a reasonable choice. In two large trials, one found an increase in the risk of new heart attacks and strokes, but the difference was relatively small. (It was 0.8% in the Evenity group and 0.3% in the Fosamax group.) But the larger trial didn’t find an increase in risk compared to a placebo. Two more trials that were published in the past year, which followed over 20,000 people on Evenity, didn’t find an increase in risk.

Even though there are some reassuring data, I still would not recommend Evenity to people who are at a high risk of heart attack or stroke (such as those with a prior history of having one). Alternatives include parathyroid hormone-type drugs; estrogen receptor modulators like raloxifine, which also reduces breast cancer risk; or denosumab (Prolia), which has the disadvantage of needing indefinite treatment. Further reassuring safety studies could get me to change my mind.

Consultation with an expert may be reasonable. I refer my patients who do not do well on first-line treatments to my colleagues in endocrinology.

Readers may email questions to Dr. Keith Roach at ToYourGoodHealth@med.

cornell.edu.