For Many, Brain Fog Lingers Post-COVID-19 Infection

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Hello again, dear readers, and welcome to a bonus letters column. We’ve had a deluge of mail, so we’ll jump right in.

-- We continue to get questions about COVID-19, which is clearly with us for the long haul. A reader in Long Beach, California, echoed several readers in wondering about the aftereffects of the illness. “Can having COVID-19 cause cognitive changes?” they asked. The answer is yes. People who have recovered from COVID-19, including those with mild illness, report ongoing changes to memory, attention, alertness and the ability to process new information. This is collectively referred to as “brain fog.” Some people also find they have an increase in anxiety and depression, as well as changes to sleep. In some cases, these resolve in the weeks after physical symptoms have ended. For some people who develop what is known as long COVID, the cognitive effects continue. The reasons for this are not clear, but both brain fog and long COVID are subjects of intensive research.

-- In writing about cardiovascular disease, we have mentioned statin drugs. These medications, which improve unhealthy blood lipid levels, reduce the risk of illness and death. This prompted a question from a reader in California: “Do statin drug have side effects?” they asked. “If so, what are they?” Yes, like many medications, statin drugs can have side effects. The most common is muscle discomfort or pain. It can range from mild to severe. In some people, liver inflammation can occur. That’s why doctors often order a liver enzyme test to act as a baseline when starting a patient on statins. It’s possible, but not common, for changes in blood sugar metabolism to occur. Some people report experiencing memory problems or confusion, which are reversed when the drugs are discontinued. Not everyone develops side effects, but certain conditions -- such as alcohol use, being older and taking multiple medications -- can increase risk. Be sure to ask your doctor to explain possible side effects when being prescribed a new drug.

-- A reader who often experiences side effects from medications asks if they can be predicted. “I was wondering if there is some blood test that can determine if a certain medication would be OK for me to take?” they wrote. Your question brings us into the expanding field of (deep breath) pharmacogenetics. It’s the study of how each person’s specific genes affect the way they respond to medications. This includes how effective the drug may be, and whether or not side effects are likely to occur. Tests are done with a cheek swab, a saliva sample or a blood draw. At this time, however, pharmacogenetic testing isn’t available for all medications. Eligible medications include a breast cancer drug known as Tamoxifen, an HIV drug, an epilepsy treatment and certain blood thinners.

As always, we appreciate your taking the time to write to us. And thank you, as well, for the very kind notes some of you have sent. We’re happy to know the column is both helpful and enjoyable.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)