Dr. Keith Roach

DEAR DR. ROACH: I am a regular reader of your column in the Sarasota, Florida, Herald-Tribune. I happen to be on 200 mg of hydroxychloroquine daily for my rheumatoid arthritis. There are mosquitos carrying Plasmodium vivax here, and so far, four people have contracted the disease. Does hydroxychloroquine offer any protection? — A.L.
ANSWER: There are four closely related parasites that cause malaria, and P. vivax is the most dangerous kind. Although malaria was declared to be eradicated from the U.S., there have been reports of sporadic cases. In 2003, for example, there were eight cases in Palm Beach County, Florida.
Prevention of malaria in these circumstances is far more effective through public health measures (such as the measures taken for travelers heading to malaria-endemic countries) than from prophylactic medicine. In this case, the Centers for Disease Control and Prevention, as well as local governments, are performing aerial and truck spraying for mosquitos. They also advise draining any items that hold water, such as old tires, bird baths, buckets and trash containers, at least once a month. Using screens on windows and doors and applying mosquito repellant are other effective ways to protect yourself against malaria.
Hydroxychloroquine is an effective treatment and preventive agent for P. vivax malaria in many parts of the world, but its use can be limited due to resistant parasites. The CDC did not report whether these cases were from hydroxychloroquine-resistant parasites, so I cannot say whether the hydroxychloroquine you’re taking is highly effective.
However, you are taking a much higher dose for your rheumatoid arthritis than the dose normally used for malaria prevention, so it may be protecting you. Since people with chronic conditions are at a higher risk, I’d urge you to be cautious and implement other measures, since the medication isn’t guaranteed protection.
I’d also recommend against readers in your area taking any kind of prophylactic medicine, since the number of cases is so small that the benefit likely isn’t worth the risk (although additional cases have been reported since you wrote your letter).
DEAR DR. ROACH: In your recent response to a question about treating obstructive sleep apnea, you mentioned the benefit of using a CPAP machine. You also mentioned that adding supplemental oxygen while sleeping could make sleep apnea worse. I am 80 now and have used two liters of oxygen at night with my CPAP for nine years. It was prescribed to help control my atrial fibrillation, which was exacerbated by my sleep apnea.
Eight years ago, I had open-heart surgery (due to an aortic aneurysm) and underwent the maze procedure, which, thankfully, resolved my AFib. Should I ask my doctor about discontinuing oxygen at night and just keep using my CPAP? — B.R.H.
ANSWER: I want to emphasize that some people need oxygen and also need treatment, such as a CPAP, for obstructive sleep apnea. The theoretical concern is in people who are using oxygen instead of a CPAP, which can slow down breathing. There is no risk in people using oxygen along with a CPAP. However, since you were using oxygen for AFib (which you no longer have), you may no longer need the oxygen, so it’s a good idea to ask your doctor about it.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.
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