Dear Dr. Roach: I am an 85-year-old woman in relatively good health. I had been taking raloxifene for approximately 45 years. My doctor at the time said that since I had a complete hysterectomy, I should be on it for the rest of my life to help prevent breast cancer and osteoporosis. My bone density is normal.

A few months ago, my provider refused to renew my prescription because she was not familiar with the medicine. I would like your opinion on this decision.

— H.W.

Answer: Raloxifene was approved for use in 1997 in the United States as prevention for osteoporosis, and in 2007, it was approved to reduce the risk of breast cancer. Most experts who prescribe raloxifene intend that the medicine should be taken long-term.

One reason that many people are concerned about taking osteoporosis medicines is that the ones that slow down bone absorption are associated with an increase risk of atypical femur fractures if they’re taken for too long. Bisphosphonate drugs, like alendronate and risendronate, are in this class. RANKL activators like denosumab are also associated with atypical femur fractures, which are devastating. These drugs are generally reevaluated and usually stopped after three to five years.

By contrast, raloxifene, which acts like an estrogen to strengthen bones (and an anti-estrogen to prevent breast cancer), does not seem to have a significant risk of developing an atypical femur fracture.

The long-term safety studies on raloxifene went on for eight years, so you are well past the published literature. Still, I don’t think that “refusing” to represcribe the medicine was the best way of handling this. If she was uncomfortable doing so, it might have been prudent to refer you to an expert in osteoporosis.

Dear Dr. Roach: We’ve lived at 6,000 feet for about 30 years. Over the years, our mean corpuscular volume (MCV) levels have slowly increased to 100 fl (the normal range being 79-97 fl). Our primary care physician and other doctors have indicated that they’ve seen larger red blood cells than what is normal in other patients as well, due to living at a high altitude.

My husband and I are in our 80s and 60s, respectively. We are healthy and have had mostly normal blood test results. If our MCV levels continue to rise, will there come a time when we should be worried about them?

— S.K.A.

Answer: MCV levels are the most common way to express the size of your red blood cells. There are many common reasons for red blood cells to be bigger than normal, including low vitamin B12, low folic acid, low thyroid levels, alcohol use, a few medicines, and a large number of blood diseases.

However, your doctors are quite right that there is a small increase in MCV levels among people living at higher altitude. On average, their levels are 6 points higher, so the normal range at high altitude might be 86-103 fl.

There isn’t a danger of large red blood cells at this size, so it’s a question of whether there might be another cause besides the altitude. If it keeps going up, your doctor might order some lab tests or refer you to a hematologist, who is an expert in blood conditions.

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.