Key takeaways:
Cephalexin is an oral antibiotic that treats many bacterial infections, ranging from respiratory and urinary tract infections to skin infections.
Cephalexin can interact with several medications, vaccines, and supplements. But cephalexin has fewer interactions than many other antibiotics.
Try to keep an updated list of your prescription and over-the-counter medications. That way, your prescriber and pharmacist can check if any medications or supplements you take interact with cephalexin.
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If you or your child have ever had a bacterial infection, your prescriber may have given you cephalexin. It’s an affordable, FDA-approved cephalosporin antibiotic that’s widely available in pharmacies across the U.S.
It’s also quite versatile. Cephalexin is used to treat a variety of bacterial infections in children and adults, such as skin, bone, and respiratory tract infections. It also treats ear, urinary, and reproductive system infections.
However, if you’ve been handed a prescription for cephalexin, you may be curious if it interacts with any medications, supplements, or foods that are part of your daily routine. It generally has fewer interactions than many other antibiotics, but it still has some notable ones to keep in mind.
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Cephalexin interactions at a glance
Possible cephalexin interactions include:
Alcohol
Metformin
Probenecid
Warfarin (Coumadin, Jantoven)
Certain live vaccines
Zinc
Furosemide (Lasix)
Mycophenolate (CellCept, Myfortic, Myhibbin)
Sucroferric oxyhydroxide (Velphoro)
Sodium picosulfate (Dulcolax Pico, Clenpiq)
Immune checkpoint inhibitors, such as pembrolizumab (Keytruda)
Cephalexin doesn’t affect certain liver enzymes (proteins) that are responsible for activating or breaking down medications. This helps limit the number of drug interactions that it has. But cephalexin can be tough on your kidneys, so it may interact with other medications that also affect the kidneys. In fact, your dose of cephalexin may be lowered if you have kidney problems.
Here, we’ll discuss some of the most common interactions with cephalexin you should be aware of.
Keep in mind: There may be other cephalexin interactions that aren’t listed here. Always keep an updated list of prescription and over-the-counter medications that you take. Include any vitamins or supplements that you take, too. Your prescriber and pharmacist can check if any of your medications interact with cephalexin.
1. Alcohol
While there isn’t a direct interaction between cephalexin and alcohol, they both can cause similar side effects. These include nausea, vomiting, and diarrhea. Using the two together could make these side effects worse. It’s best if you don’t drink while taking cephalexin.
Plus, certain cephalosporins — such as cefotetan and cefoperazone — can cause a disulfiram-like reaction when paired with alcohol. While cephalexin isn’t one of the common culprits, it’s chemically related to these antibiotics. A disulfiram-like reaction is a rare, but severe, side effect that can cause:
Nausea
Vomiting
Facial flushing
Face and mouth swelling
In general, it’s best to avoid alcohol while you have an infection. Alcohol can also affect the immune system and make it harder for you to heal from an infection.
2. Metformin
Metformin is one of the most popular medications in the U.S. — it’s most commonly used to manage blood glucose (blood sugar) levels in people living with Type 2 diabetes. Cephalexin can raise the amount of metformin in the body by lowering the amount that’s cleared by the kidneys.
This interaction is mentioned in cephalexin’s labeling, but there’s not a lot of data about it. A small study showed that taking one dose of cephalexin with metformin increased metformin levels in the body. However, the study authors didn’t conclude what the clinical effects of this were. There isn’t any widely known data that speaks to the effects of multiple cephalexin doses on metformin.
Cephalexin dosages: View the recommended dosages of cephalexin and when adjustments may be necessary.
Risk management: Learn more about the potential side effects of cephalexin and what you can do to manage them.
Looking for ways to save? Find out the price of cephalexin without insurance and how you can lower your out-of-pocket costs.
It’s rare for metformin by itself to cause hypoglycemia (low blood sugar). But in theory, this interaction could lower your blood sugar too much. Your healthcare team may recommend checking your blood sugar at home more frequently while taking metformin and cephalexin.
3. Probenecid
Probenecid is a medication that treats gout. Cephalexin levels in the body can jump too high when it’s combined with probenecid.
Typically, it’s recommended to avoid taking these medications at the same time. Together, the combination can raise the risk of experiencing cephalexin side effects, such as nausea, vomiting, or diarrhea. It can also place added stress on the kidneys — especially if you already have kidney problems. Your prescriber may adjust the dosage for one or both of these medications if you end up taking them together.
However, drug interactions sometimes can be used as an advantage. Another FDA-approved use of probenecid is boosting the antibiotic activity of certain penicillin antibiotics. This can make the antibiotic more effective in certain situations. Cephalexin isn’t a penicillin antibiotic, but some studies have also reported that probenecid can boost cephalexin levels. More research is needed to confirm this effect.
4. Warfarin
Warfarin (Coumadin, Jantoven) is a blood thinner used to treat and prevent blood clots. If you take warfarin, your prescriber and pharmacist have likely mentioned that it has a lot of interactions, including interactions with your diet.
Medications are no exception to this. Many medications can increase the risk of bleeding when taken with warfarin. Other medications can cause warfarin to be less effective — raising the risk of a blood clot.
Cephalexin can worsen the risk of bleeding when used with warfarin. Cephalexin has a lower risk of causing this interaction than other antibiotics, but your healthcare team may still perform frequent blood tests out of caution while you’re taking cephalexin. This will help them see if your warfarin dosage needs an adjustment.
Make sure to watch for any signs or symptoms of bleeding, including bruising, nosebleeds, or blood in your urine. Report them to your healthcare team right away.
5. Certain live vaccines (cholera, typhoid, BCG)
Antibiotics — including cephalexin — can make live oral typhoid (Vivotif) and cholera (Vaxchora) vaccines less effective. The live BCG vaccine for tuberculosis may also interact with antibiotics. These interactions could cause your body to not build up a strong enough immune response to fight cholera, typhoid fever, or tuberculosis infections.
If you’re taking cephalexin and need these vaccines, it’s best to separate them. This will help make sure you get the most vaccine benefits. Wait to get the Vivotif vaccine for at least 72 hours after finishing your last dose of cephalexin. And after finishing cephalexin, wait at least 14 days to get the Vaxchora vaccine. Your prescriber and pharmacist can help answer any travel vaccine questions you may have.
While not typically used in the U.S., the BCG vaccine is given in many countries to prevent tuberculosis. Research hasn’t shown a recommendation for how to separate antibiotics from the BCG vaccine. But your healthcare team may decide to separate them out so you get the full vaccine benefits.
6. Zinc
Zinc is a mineral found in a variety of dietary supplements at your local pharmacy, and it comes in various doses.
Studies show that zinc can lower the absorption of cephalexin in the body. This may cause cephalexin to be less effective at fighting infections. Separating zinc and cephalexin can help prevent this interaction. If you want or need to take zinc — or multivitamins that contain zinc — doing so at least 3 hours after your cephalexin dose helps avoid this issue.
Frequently asked questions
To be on the safe side, wait at least 8 hours after your last dose of cephalexin before drinking alcohol. Your body should clear most of the medication from your system by then. Though, if you have any kidney problems, you may want to wait up to 5 days before drinking. This is because your kidneys are in charge of filtering cephalexin and getting rid of it through your urine.
Alcohol can also make it harder to heal from an infection because of how it affects your immune system. If you’re still recovering, it’s best to avoid alcohol until you’re feeling better.
There are no strict food restrictions to worry about while taking cephalexin. But remember that this antibiotic can sometimes cause nausea, diarrhea, or an upset stomach. You may want to avoid taking cephalexin with potential trigger foods, such as dairy products, spicy dishes, or overly acidic foods.
You can take over-the-counter (OTC) pain relievers, such as acetaminophen (Tylenol), while taking cephalexin. There are no major drug interactions between these common OTC pain medications and cephalexin.
That said, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve) may also upset your stomach. And if you have any kidney problems, your healthcare team might suggest avoiding NSAIDs. Ask a healthcare professional if NSAIDs are OK for you to take.
Yes, it’s OK to drink coffee while taking cephalexin. While some data suggests that caffeine — the active ingredient in coffee — may boost the activity of a variety of antibiotics, this doesn’t appear to be the case for cephalexin.
To be on the safe side, wait at least 8 hours after your last dose of cephalexin before drinking alcohol. Your body should clear most of the medication from your system by then. Though, if you have any kidney problems, you may want to wait up to 5 days before drinking. This is because your kidneys are in charge of filtering cephalexin and getting rid of it through your urine.
Alcohol can also make it harder to heal from an infection because of how it affects your immune system. If you’re still recovering, it’s best to avoid alcohol until you’re feeling better.
There are no strict food restrictions to worry about while taking cephalexin. But remember that this antibiotic can sometimes cause nausea, diarrhea, or an upset stomach. You may want to avoid taking cephalexin with potential trigger foods, such as dairy products, spicy dishes, or overly acidic foods.
You can take over-the-counter (OTC) pain relievers, such as acetaminophen (Tylenol), while taking cephalexin. There are no major drug interactions between these common OTC pain medications and cephalexin.
That said, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve) may also upset your stomach. And if you have any kidney problems, your healthcare team might suggest avoiding NSAIDs. Ask a healthcare professional if NSAIDs are OK for you to take.
Yes, it’s OK to drink coffee while taking cephalexin. While some data suggests that caffeine — the active ingredient in coffee — may boost the activity of a variety of antibiotics, this doesn’t appear to be the case for cephalexin.
The bottom line
Cephalexin can interact with certain medications and supplements, such as metformin, warfarin, and zinc. It may also interact with live cholera and typhoid vaccines. Let your prescriber and pharmacist know about all the medications and supplements you take — this will help them monitor for any potential cephalexin interactions. And if you experience any new or concerning side effects, reach out to a healthcare professional as soon as you can.
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References
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