When you’ve got a runny nose or stuffy head, you may want to reach for an over-the-counter (OTC) cold and flu medicine. But these drugs aren’t for everyone. While they may help relieve your symptoms, some of these products can cause problems if you have certain health conditions. 

Here’s a look at how common ingredients in cold and flu medicines can interact with chronic health conditions. Make sure to check all labels carefully, since some cold and flu medicines have more than one active ingredient. 


These medicines help ease a stuffy nose. Decongestants include Sudafed PE (phenylephrine) and Sudafed 12-Hour (pseudoephedrine). Decongestants are also available in nasal sprays and drops. 

Decongestants can raise blood pressure and blood glucose levels. They also can interact with certain prescription medicines. Check with your doctor before taking a decongestant if you have any of these conditions: 

  • Asthma
  • Diabetes
  • Glaucoma
  • Heart conditions
  • High blood pressure
  • Prostate problems 
  • Thyroid conditions


Antihistamines can ease coughing, sneezing, and a runny nose. But if you have closed-angle glaucoma (also called narrow-angle glaucoma or angle-closure glaucoma), you’ll want to look for another treatment option. Antihistamines can cause your pupils to enlarge, which can cause problems with this type of glaucoma. 

Some common antihistamines include Benadryl (diphenhydramine), Chlor-Trimeton (chlorpheniramine), and Claritin (loratadine). Sometimes antihistamines are also in multisymptom cold and flu medicines, so read labels carefully or ask your doctor what to take. 

If you have another type of glaucoma, check with your doctor before taking antihistamines, just to be safe. 

Pain Relievers

Pain relievers can ease the aches and pains of a cold or flu and help reduce fever. Common pain relievers include aspirin, Advil (ibuprofen), Aleve (naproxen), and Tylenol (acetaminophen). Be careful about taking a pain reliever if you have one of the following conditions:

  • Diabetes: Large doses of aspirin can lower your blood glucose. Ask your doctor if aspirin is OK for you or if you should use another type of pain reliever. 
  • Asthma: Studies show that pain relievers can make asthma symptoms worse. Talk with your doctor or pharmacist if you have questions about other options for pain relief. 

Know All the Ingredients

Many cold remedies contain several ingredients. Some of these can interfere with the following health conditions:

  • High blood pressure: Check all medicine labels for sodium. Some OTC cold medicines contain a lot of sodium, which can raise your blood pressure. Ask your doctor or pharmacist which medicines are safe to take. 
  • Diabetes: Some OTC medicines also contain a lot of sugar. If you have diabetes, make sure you check the labels on all OTC cold medicines to make sure they don’t have large amounts of sugar. Or ask your doctor or pharmacist about sugar-free options. 

Key Takeaways

Before taking cold and flu meds, you’ll want to read all the labels and choose medicines that treat your symptoms. If you have a chronic health condition like high blood pressure or diabetes, take the added precaution of checking with your doctor or pharmacist. They will know if the ingredients are likely to cause problems for you.