Be cautious using sleep aids for pain

Dear Dr. Roach: I have peripheral neuropathy due to a pinched nerve. I get some relief from it, but it still hurts and keeps me from sleeping. My doctor recommended a Tylenol PM, and it helps me sleep well for six or seven hours most nights. But some nights I wake up hurting and have trouble getting back to sleep. Then I can take two regular Tylenol and, most nights, get back to sleep after about 30 minutes. My concern is the long-term use of the Tylenol PM. — W.H.

Tylenol PM contains both acetaminophen (the pain reliever in plain Tylenol) and diphenhydramine (an antihistamine with sedating qualities). Both of these components have some potential for harm.

Excess amounts of acetaminophen can be toxic to the liver. Healthy adults should take no more than 4,000 mg per day (that’s eight extrastrength tablets, but since other medications also may contain acetaminophen, it’s the total amount that needs to be considered). People with mild liver problems should not exceed 3,000 mg per day, or should discuss with their doctor.

Diphenhydramine potentially can cause a large number of problems, but most people tolerate it reasonably well. It is not my first choice for a sleep aid, as it increases risk for falls and automobile accidents. Diphenhydramine is associated with an increased risk of developing dementia; however, it’s not yet clear whether the diphenhydramine really causes the dementia.

There are no risk-free medications. One option I would consider is trying regular Tylenol (not the PM) at bedtime. It may be that it’s the extra pain relief that is helping you sleep, and you may not need the diphenhydramine at all.

Finally, a recent study showed that changing to a plant-based diet improved symptoms of diabetic neuropathy: It may benefit you.

Write to Dr. Roach at ToYourGoodHealth @med.cornell.edu.