The holidays are supposed to be a festive, joyful time. Paradoxically, that can put some of us under stress as we try to shop for gifts, put up decorations and organize parties.

With too many lists and too little sleep, it’s no wonder that even sensible people might reach for something to take the edge off. Whether it’s a pain reliever for a stress headache, a nightcap to try to get some sleep or a prescription for a back spasm, you may have no warning that some of these seemingly reasonable remedies might turn a simple night of celebration into a medical mess.

Nearly everyone knows not to drink and drive, but far fewer people realize that combining alcoholic beverages with medications can be just as risky. Even one glass of holiday cheer can behave badly when combined with the wrong medication. Some people learn this the hard way: sudden dizziness after a single drink, a splitting headache that gets worse instead of better or a blood-alcohol reading that defies logic. Are these urban legends? No, they’re classic signs of drug-alcohol interactions.

Here’s the twist most partygoers don’t expect: The danger doesn’t just belong to “heavy drinkers.” Plenty of Americans barely drink at all, until the holidays hit, and they’re handed a flute of champagne or a mug of spiked cider. A persistent host may inadvertently pressure a non-drinker with a smile that says, “Oh come on, live a little.”

You can’t always feel the warning signs of a drug and alcohol interaction. Some sneak up silently, such as liver damage. There is also slowed reaction time or more intense sedation.

Very few people realize that some medications could affect blood alcohol levels. An over-the-counter heartburn medicine seems innocuous and might be just the ticket after too many sausages or holiday cookies. Research indicates, though, that drugs such as cimetidine or famotidine may impact blood alcohol levels (Expert Opinion on Drug Safety, Oct. 1, 2018). This interaction has been controversial for decades and some researchers maintain that it has little clinical significance. Nevertheless, we think it is worth a warning. The blood pressure medicine verapamil can also raise blood alcohol levels.

Antidepressants, anxiety meds, sleep aids, antibiotics or pain relievers could turn a casual toast into trouble. Some drug and alcohol combinations spark odd behavior or memory gaps that leave people confused or embarrassed.

One other often overlooked complication of alcohol involves the popular pain reliever acetaminophen (Tylenol). This ingredient is found in hundreds of over-the-counter and prescription medications.

Many people never bother to read the ingredient list or the warnings on their cold or flu medicines, cough remedies or nonprescription pain relievers. If they did, they might discover that acetaminophen does not mix well with alcohol.

Physicians and pharmacists should warn patients about the potential for drug and alcohol interactions, but sometimes they forget. At this time of year, everyone is distracted.

If you would like to learn more about these topics, you can request a free copy of “Graedons’ Guide to Drugs that Interact with Alcohol.” This downloadable pdf may be found in the Health Guides section of the store at www.PeoplesPharmacy.com.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com.