Q: I have had restless legs syndrome for as long as I can remember. I was given Mirapex in 2010, and the doctor maximized the dose in 2011.

I NEVER gambled or shopped excessively in my life before starting this medication. I have since gambled away my entire savings, lost my marriage, lied about going to work, binge shopped and hid things, which ultimately ruined the life I worked hard to build.

When I learned about these side effects, I went to my doctor and asked to be taken off the medicine. Can you believe he actually told me that he didn’t know about these side effects? It has taken a lot in the past four years to try to rebuild my life, forgive myself and control behaviors that I learned over those years.

I now take carbidopa/levodopa without any problem.

A: Many people are shocked to learn that some medications have been linked to compulsive behavior, such as gambling, binge drinking, shopping and even hypersexuality. Such behaviors are associated with the antipsychotic drug aripiprazole (Abilify) and drugs used to treat Parkinson’s disease and RLS, pramipexole, ropinirole and rotigotine.

These drugs affect the brain chemical dopamine. Researchers writing in the journal JAMA Internal Medicine (December 2014) called for boxed warnings on the prescribing information and vigilant monitoring of patients taking such medications.

Q: I have hypothyroidism and have been taking generic levothyroxine for a few years. My doctor and I have struggled to find the correct dosage and recently settled on 125 mcg daily.

I asked my doctor to prescribe branded Synthroid, because I read it is better. He did so, at the same dosage level as the generic.

Within one day of taking Synthroid, I feel as if I am about to explode. I am anxious, and my heart is racing. I also have diarrhea. Is there an explanation?

A: We have heard from many people that switching from branded to generic levothyroxine or vice versa can result in symptoms. Excess thyroid hormone can cause rapid heart rate, sweating, anxiety, tremors, diarrhea and irritability. Such a switch may require a dose adjustment.

Q: I recently tried to refill my prescription for atenolol and was informed there was a nationwide shortage. My drugstore was out of it.

I am loath to switch to metoprolol, another beta blocker, and hope I can find more atenolol soon. Is there any indication when this shortage will end?

A: Drug shortages have become commonplace, even for old generic drugs like atenolol. The Food and Drug Administration anticipates that atenolol should become available again in February. In the meantime, metoprolol might substitute, though your doctor will need to make that determination.

Q: Years ago, I was getting cold sore after cold sore after cold sore. Then I read about trigger foods and realized that the cashews I was enjoying probably were a big source of the problem.

I began taking L-lysine daily. I later read that one shouldn’t take it all the time. So I now go easy on my trigger foods and just take some L-lysine if I feel a cold sore coming or if I eat some chocolate or nuts. This seems to work for me.

A: The idea of reducing cold sore susceptibility by reducing arginine intake and increasing lysine goes back to the early 1980s (Chemotherapy, 1981). A small placebo-controlled trial found that L-lysine supplements reduced the number of cold sores and their severity and duration (Dermatologica, 1987).

Although cashews are not technically nuts, they are rich sources of the amino acid arginine. So it makes sense for you to exercise restraint when consuming cashews.

In their column, Joe and Teresa Graedon answer letters from readers. Send questions to them via www.peoplespharmacy .com.