If you have heart disease

While low-dose aspirin can help prevent heart attack, other painkillers in the nonsteroidal anti-inflammatory drug family (NSAIDs)—which include ibuprofen—have been associated with an increase in the chance for heart attack or stroke. A 2017 British Medical Journal study reported a 20 to 50 percent elevated risk of heart attack among people who used NSAIDs daily for a week or more. The increased risk associated with ibuprofen could be as high as 75 percent. The greatest danger occurred within the first month of NSAID use and at high doses. Those with heart disease or at risk for heart disease should be especially mindful of these findings, though the elevated risk affects everyone, says Catherine Sherwin, PhD, chair of the clinical pharmacology track at the American Association of Pharmaceutical Scientists PharmSci 360 Meeting. If you’re taking blood-pressure medication, be especially cautious—NSAIDs could make them less effective. Talk to your doctor about alternative medications to treat your pain, whether it’s, say, a Tylenol for a headache or physical therapy for back pain.

If you’re on anti-clotting meds

Anticoagulants (such as Warfarin) and antiplatelets (such as Plavix) prevent blood from clotting easily. Anticoagulants are typically prescribed for people at high risk for stroke (such as those with atrial fibrillation or artificial heart valves), or those who’ve suffered from a pulmonary embolism; antiplatelets are usually advised for those who’ve already suffered a heart attack or stroke, as a way to prevent it from happening again. The problem? ‘The combination of these drugs with ibuprofen could significantly increase the risk for bleeding complications,’ says David Craig, PharmD, pharmacist lead at the Moffitt Cancer Center and American Pain Society E-News editor. So instead, discuss other options with your doctor; for instance, you may consider celecoxib, which may be less likely to induce bleeding.

If you have gastrointestinal issues

NSAIDs not only irritate the lining of the stomach and intestines, but they can also reduce blood flow in the area and impair its ability to fix itself. So if you already have digestive issues, such as inflammatory bowel disease (IBD), you probably wouldn’t want to pop an Advil or Motrin or any other NSAID. They’re not effective for pain associated with IBD and, in the cases where you’re suffering from other achy issues, you’re better off talking to your doctor about alternative treatments. Acetaminophen may be a good option for headache pain, for instance. According to Venkata Yellepeddi, Ph.D., adjunct assistant professor in pharmaceutical chemistry at the University of Utah, if you have trouble with menstrual cramping, birth control pills could help

If you’re pregnant

NSAIDs have been found to harm the fetus, raising the risk of miscarriage in early pregnancy and heart defects in the third trimester. What’s more, a recent Human Reproduction study on fetal tissue suggests an association between women who have taken ibuprofen during their first trimester and a subsequent reduction in egg development in the fetal ovaries—which could compromise a daughter’s future fertility. Ibuprofen is also not a good idea during labor and delivery since it could lead to prolonged bleeding. If you’re in need of pain relief at some point over the course of your pregnancy, check with your doctor.

If you have a UTI

A few years ago, researchers reported that NSAIDs may be useful for treating urinary tract infections. Besides possibly soothing pain, they may reduce recurrence, as well as help curb the use of antibiotics—a good thing, given the threat of antibiotic resistance. The hitch? NSAIDs might actually not do any of that: ‘There’s conflicting evidence in the literature on the effectiveness of ibuprofen, and it’s dependent on the antibiotic with which it’s compared,’ says Sherwin. In addition, a PLOS Medicine study reports that women who took ibuprofen only to treat a UTI took an average of three days longer to heal than those on antibiotics, and they had a slightly higher risk of complications. 

If you have arthritis

Arthritis sufferers have long taken ibuprofen and other NSAIDs for arthritis pain. But because of its negative effects on the gastrointestinal and cardiovascular system, certain patients—particularly if they had a history of stomach or heart issues—should probably think twice before popping an ibuprofen.

A 2017 European Heart Journal paper compared the blood pressure effects of different types of NSAIDs (ibuprofen, naproxen, and celecoxib) on osteoarthritis and rheumatoid arthritis patients. The verdict? All the drugs were associated with an increased risk of hypertension—and ibuprofen had the worst impact, with 23.2 percent of patients on the drug going from normal to hypertensive, compared to 19 percent for naproxen and 10.3 percent for celecoxib.

What’s more, for those with rheumatoid arthritis, NSAIDs are not able to control the inflammation enough to prevent further joint damage. What can? Disease-modifying anti-rheumatic drugs (DMARDs) as well as biologic response modifiers (or simply, biologics). Non-drug options—like exercise, physical therapy, and warm baths—can also offer some pain relief.

If you enjoy wine or cocktails

We’ve been there. You’ve got plans to meet a friend for drinks, and you’ve got an awful headache. But think twice before popping an Advil just before running out for that cocktail. Alcohol can irritate the stomach and so can NSAIDs. Put the two together, and you just compounded your chances of damaging your tummy. ‘Alcohol should be avoided due to increased risk of stomach ulcers,’ says Sherwin, who is also division chief of pediatric clinical pharmacology at the University of Utah School of Medicine. Making matters worse, the one-two punch can also up your risk of liver damage.

If you’re about to tackle a really tough workout

Die-hard athletes sometimes take an Advil before, say, a long run. But that may be, at best, a waste of time and potentially harmful at worst. ‘Painkillers are a chemical Band-Aid,’ says Lillie Rosenthal, DO, a medical advisory board member at MedShadow Foundation, a nonprofit group that educates patients on long-term drug safety and efficacy. ‘You have to listen to the body and figure out the cause,’ says Dr. Rosenthal, who specializes in physical medicine and rehabilitation.

With ibuprofen muting the pain, you may not know if you’re overexerting yourself, or it may prevent you from slowing down or getting help when it’s needed. What’s more, if you’re working out extremely hard—as in ultramarathon hard—taking ibuprofen can exacerbate the kidney damage that’s sparked by rigorous exercise.

In a 2017 BMJ Emergency Medicine paper, ultramarathoners who took ibuprofen over the course of 50 miles (for a total of 1200 mg) were about 18 percent more likely to experience acute kidney injury than those who took a placebo. Extreme workouts tax the kidneys by drawing blood to the muscles for a prolonged period of time; taking ibuprofen—which reduces prostaglandins, which then, in turn, diverts blood flow from the kidney—exerts a double whammy on the kidneys. Also, an ibuprofen may not even be that helpful. In a small 2015 study published in the Journal of Athletic Training, researchers rounded up experienced runners, had them do a baseline workout, and then induced muscle pain in their legs through strenuous exercise (ouch!). Later, the subjects were either given ibuprofen or placebo and then told to do a follow-up workout. The difference? Essentially, none. One possible reason, say the researchers, may be that the drug’s effect on the heart may compromise oxygen uptake and negate any gains in pain reduction.

If you have asthma

Ibuprofen and other NSAIDs quell inflammation by inhibiting an enzyme that reduces the production of substances called prostaglandins, which help with healing. The issue is that interfering with prostaglandins could exacerbate asthma. That’s why the insert in your ibuprofen packages warns asthma sufferers to exercise caution, says Marilyn E. Morris, PhD, SUNY Buffalo distinguished professor and chair of the department of pharmaceutical sciences. ‘Asthmatics who have a demonstrated sensitivity to NSAIDs, like ibuprofen, could have a life-threatening bronchospasm event,’ explains Craig. ‘These patients should talk to their doctors about alternative options to manage pain.’