As you age it is not uncommon to have occa- sional periods of forgetfulness or “brain fog” where you can’t think clearly or have trouble multitasking and comprehending information. Is it an unfortunate reality of aging or something that can be corrected? It is not wise to ignore it thinking it is your age because the medications you are on may be the real culprit.

“Memory issues can be common side effects for many drugs older adults often take for the first time in their lives,” says Dr. Mark Albers, a neurologist with the McCance Center for Brain Health at Harvard-affiliated Massachusetts General Hospital. “While these drugs don’t affect everyone equally, people should examine any new medication or changes in dosage and frequency if they suddenly have problems with memory and thinking.”

Multiple factors

There are several reasons medication can affect memory more as you age.

Weak blood-brain barrier. The blood-brain barrier allows blood to carry nutrients and oxygen into the brain while blocking toxins and other harmful substances. This wall weakens with age, and drugs can “leak” into the brain, affecting cognitive functions.

Polypharmacy. Many older adults need multiple medications to treat one or more conditions, a situation known as polypharmacy. It is also common for older people to take drugs in higher doses and with greater frequency than younger people.

Sensitivity. Older people tend to metabolize drugs more slowly, making their bodies more sensitive to medications and more vulnerable to side effects.

Track your memory problems

If you suspect a drug is causing memory problems, don’t stop taking it on your own. Instead, track your symptoms for one to two weeks and then share the results with your doctor. Make a note of the following:

• when you usually take the drug

• whether you take it with or without food

• what type of memory problems you experience and how long they last

• when the issues usually arise, such as a specific period after taking the drug or when you’re trying to complete certain tasks.

Be as detailed as possible. The more information you can provide, the better chance your doctor can identify a pattern to determine if and how a drug may be the problem.

Drugs of addiction

Medications usually affect memory by interfering with how hormones and neurotransmitters transmit signals between brain cells.

You often know if a drug causes memory problems soon after taking it, according to Dr. Albers. Some memory issues are temporary or come and go. Others are more frequent and begin to affect quality of life.

“It depends on how much you take, how your body metabolizes the drug, and your individual sensitivity,” says Dr. Albers. “Problems also could be caused by undesirable drug interactions.”

While many medications can cause brain fog and other memory problems, sleep and pain drugs are the most common culprits. These are the medications that have the added danger of being addictive.

Sleep aids. Over-the-counter sleep aids often contain diphenhydramine, an antihistamine with anticholinergic properties. Anticholinergic drugs are well known to impair cognitive function in older people. Prescription sleep drugs, such as zolpidem (Am- bien), can diminish activity in parts of the brain involved in how events are transferred from short-term to long-term memory, which affects memory recall.

Pain medications. Most of the drugs used to treat chronic pain can cause confusion and memory is-

sues. The list includes opioid analgesics, tricyclic antidepressants such as amitriptyline (Elavil, Endep) and nortriptyline (Aventyl, Pamelor), and gabapentin (Neurontin).

The good news is that these problems often go away with modifications. For instance, your doctor might suggest you switch to a different drug, change the dose or frequency, or go off the drug entirely if your health has improved. “Sometimes, just changing when you usually take your medication can make a difference,” says Dr. Albers.

If you take multiple medications, the approach may be trial-and-error: your doctor will try modifying one drug at a time, and if your condition doesn’t change, will move to the next one and repeat the process.