Cephalexin vs. Amoxicillin for Skin Infection and Ear Infection: Important Differences and Potential Risks.

Key takeaways

Cephalexin (Keflex) and Amoxicillin (Amoxil) are both antibiotics used to treat bacterial infections, such as urinary tract infections (UTIs) and ear infections. However, they belong to different medication classes. Cephalexin is a cephalosporin antibiotic, while Amoxicillin is a penicillin antibiotic. Cephalexin is available as capsules, tablets, and liquid suspensions, and is typically taken 2 to 4 times a day. Amoxicillin comes in tablets, capsules, chewable tablets, and liquid forms, and is usually taken 2 to 3 times a day. Both medications are available as lower-cost generics. Common side effects for both include nausea, vomiting, and diarrhea, but Amoxicillin can also cause a rash. Cephalexin may interact with metformin, probenecid and warfarin while Amoxicillin can interact with probenacid, warfarin and allopurinol. If you have a penicillin allergy, you might also be allergic to Amoxicillin, but the risk is lower with Cephalexin.

Cephalexin

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Amoxicillin

(Amoxil)

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Summary for Cephalexin

Prescription only

Cephalexin, also commonly known as Keflex, is a cephalosporin antibiotic for people ages 1 year and older. It can treat many types of bacterial infections. This includes ear infections, skin infections like cellulitis, urinary tract infections (UTIs), and strep throat. Cephalexin comes as capsules, tablets, and a liquid suspension. It's taken by mouth 2 to 4 times per day. Side effects can include nausea, vomiting, and diarrhea. Cephalexin is a generic medication; its brand name Keflex is no longer available.

Indications for Cephalexin

Respiratory tract infections (e.g., strep throat)
Ear infections
Skin infections (e.g., cellulitis)
Bone infections
Urinary tract infections (UTIs)
Reproductive system infections (e.g., prostatitis)

Pros and Cons for Cephalexin

Pros

Treats several common types of bacterial infections
Okay for children as young as 1 year old to take
Available as a liquid for people who have trouble swallowing pills

Cons

Usually need to take a few times per day
Might not be able to take if you're allergic to penicillins or other cephalosporin antibiotics
Not recommended for the cold or flu (these are viral illnesses, not bacterial infections)

Common Side Effects for Cephalexin

Diarrhea
Nausea
Vomiting
Indigestion
Stomach pain

Warnings for Cephalexin

Allergic reactions
Diarrhea from Clostridioides difficile infection
Seizures
Higher risk of bleeding
Possible development of drug-resistant bacteria

Summary for Amoxicillin

Prescription only

Amoxicillin (Amoxil) is a penicillin antibiotic that's used to treat a wide variety of bacterial infections, such as sinus infections, ear infections, strep throat, and urinary tract infections (UTIs). It's available as oral pills, a chewable tablet, and an oral liquid. Amoxicillin (Amoxil) is well-tolerated, but possible side effects include diarrhea, vomiting, and rash.

Indications for Amoxicillin

Upper respiratory tract infections (ear, nose, and throat infections)
Lower respiratory tract infections (e.g., pneumonia, bronchitis)
Urinary tract infections (UTIs)
Skin infections (e.g., cellulitis)
Helicobacter pylori infection (adults only)

Pros and Cons for Amoxicillin

Pros

Works well to treat many different bacterial infections
Can use for adults and children
Available in many forms (e.g., oral tablet, chewable tablet, capsule, liquid)
Liquid form comes in many different flavors to make it taste better

Cons

Might need to take up to three times per day
Can cause stomach side effects like nausea, vomiting, and diarrhea
Not the best option if you have severe kidney problems
Might not be able to take this medication if you've had a severe allergy to penicillin