Q: I’ve had fungus in all my toenails since the summer I hiked for three weeks in snow. Most of my toenails and the outer skin of my feet sloughed off then, about 44 years ago.

I asked my physician to prescribe Jublia despite its low cure rate. At the pharmacy, I was told it needed preapproval. If I wanted to pay cash, though, a 4 milliliter (ml) bottle to be applied daily for 10 months would cost me $418 per bottle! I laughed and said, “No thanks.” I can live with this after all these years.

A: Efinaconazole (Jublia) is a new topical antifungal medication that is being widely advertised on television. Actual cure rates are not mentioned in the commercials.

There were two clinical trials to get Food and Drug Administration approval. In one, a “complete cure” was achieved in 17.8 percent of the subjects after 48 weeks of Jublia applications. In the other study, 15.2 percent of the volunteers achieved a cure after 48 weeks.

Chain pharmacies near us charge between $539 and $589 for a 4 ml bottle. You would need at least one drop per infected toe each day. If all your nails are infected, that could be 12 drops daily (the big toes get two drops). There are roughly 80 drops in a 4 ml bottle, so one bottle would last about a week. After 48 weeks, you could be out more than $20,000 if your insurance company won’t cover the cost.

Q: My thyroid gland was removed, and I have been on Synthroid or generic levothyroxine for more than 20 years. Although I am 52, I feel 20 years older.

I am always tired, and my muscles ache. One doctor told me I had to learn to live with these symptoms, but they are getting worse. It feels like the generic levothyroxine varies in dose from month to month. What can I do to feel better?

A: Questions about the variability of generic levothyroxine pills remain controversial. We generally tell people to stick with a single manufacturer if its product works for them.

A far more contentious issue is whether levothyroxine alone is appropriate for all hypothyroid patients. That has been the standard of treatment for more than half a century, but recent research has helped to explain why some people say they don’t feel good on levothyroxine (T4) alone (Journal of Clinical Endocrinology and Metabolism, May 2009).

In the body, an enzyme converts T4 to T3, the active hormone, by knocking off one iodine atom. A genetic variant of the enzyme occurs in about 15 percent of people. These are the folks who feel better if they get T3 along with levothyroxine to treat their thyroid condition.

For more details about this treatment program, you can download our newly revised Guide to Thyroid Hormones. Look for it under Health Guides at www.PeoplesPharmacy.com.

Q: My doctor prescribed drugs to treat my high blood pressure and also suggested a low-salt diet. My blood pressure stubbornly remained somewhat high.

I talked to the nurse, and he suggested not worrying so much about the salt in my diet and trying to increase my potassium intake. My blood pressure is now normal.

A: Salt may not be the villain everyone thinks it is (JAMA Internal Medicine online, Jan. 19, 2015). Some research shows that the ratio of sodium to potassium is probably more important in determining blood pressure than either mineral alone (Advances in Nutrition, November 2014). Increasing potassium intake through diet can indeed lower blood pressure (BMJ, April 4, 2013).

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of this newspaper or email them via their Web site: www.PeoplesPharmacy.com. Their newest book is “Top Screwups Doctors Make and How to Avoid Them.”