Are you a healthcare professional? Join GoodRx for HCPs

Compare Bactrim vs. Amoxicillin

Head-to-head comparisons of medication uses, side effects, warnings, and more.

Key takeaways

Sulfamethoxazole/trimethoprim (Bactrim, Septra) and amoxicillin (Amoxil) are both antibiotics used to treat bacterial infections, including urinary tract infections (UTIs) and ear infections. However, they belong to different medication classes. Sulfamethoxazole/trimethoprim is a combination of a sulfonamide and an antifolate, while amoxicillin is a penicillin antibiotic. Sulfamethoxazole/trimethoprim is available in oral and injectable forms, whereas amoxicillin is available as oral tablets, capsules, chewable tablets, and liquid. Both medications can cause side effects like nausea, vomiting, and diarrhea, but sulfamethoxazole/trimethoprim can also cause skin sensitivity to sunlight and changes in blood sugar levels. Amoxicillin is generally safe during pregnancy, while sulfamethoxazole/trimethoprim is not recommended. Additionally, sulfamethoxazole/trimethoprim can interact with warfarin and dofetilide (Tikosyn), whereas amoxicillin can interact with medications like warfarin and allopurinol. Both medications require a prescription and should be taken as directed by your healthcare provider.

Sulfamethoxazole/trimethoprim
Amoxicillin (Amoxil)
Sulfamethoxazole/trimethoprim
Amoxicillin (Amoxil)
Summary of Bactrim vs. Amoxicillin
Summary for Sulfonamide antibiotic
Prescription only
Sulfamethoxazole/trimethoprim (sometimes known as SMZ/TMP) is a combination medication containing an antifolate and sulfa antibiotic. It's used to treat different types of infections, such as urinary tract infections (UTIs), ear infections, and lung infections. This antibiotic has two different brand names, Bactrim and Septra, and it's also available as a lower-cost generic. It's a tablet that's taken by mouth, typically twice daily for most types of infections. This antibiotic also comes as a suspension under the brand name Sulfatrim for people who can't swallow tablets and as an injection for people in the hospital. Common side effects include nausea, diarrhea, and rash.
Summary for Penicillin antibiotic
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 of Bactrim vs. Amoxicillin
Indications for

•Urinary tract infection (UTI)

•Lower respiratory tract infection (e.g., Pneumocystis pneumonia, infections related to bronchitis)

•Diarrhea caused by Shigella (shigellosis)

•Travelers' diarrhea - tablet or liquid only

•Ear infections - tablet or liquid only

Indications for

•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 of Bactrim vs. Amoxicillin
Pros and Const for Sulfonamide antibiotic
Pros

•Treats many types of bacterial infections

•Can be given to children as young as 2 months old to treat certain infections

•Available as a lower-cost generic

Cons

•Can upset your stomach and make your skin more sensitive to the sun

•Not the best choice for people with liver or kidney problems

•Not recommended if you're pregnant

•Can't take if you have a sulfa allergy

Pros and Const for Penicillin antibiotic
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
Common Side Effects of Bactrim vs. Amoxicillin
Common Side Effects for

•Nausea

•Vomiting

•Diarrhea

•Loss of appetite

•Rash

•Hives

•Skin sensitivity to sun or light

Common Side Effects for

•Diarrhea

•Nausea

•Vomiting

•Rash
Warnings of Bactrim vs. Amoxicillin
Common Side Effects for

•Not for use during pregnancy

•Severe allergic reactions and skin reactions

•Low platelet counts and risk for bleeding

•Diarrhea from Clostridioides difficile infection

•Low sodium levels and high potassium levels

•Blood cell-related problems

•Problems with processing phenylalanine - for people with phenylketonuria (PKU) only

Common Side Effects for

•Severe allergic and skin reactions

•Diarrhea from Clostridioides difficile infection

•Development of drug-resistant bacteria
Prices with our coupons for Bactrim vs. Amoxicillin
Learn more about Sulfamethoxazole/trimethoprim
Learn more about Amoxicillin

Browse medications

View All

Research prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.

Compare Bactrim vs. Amoxicillin

Key takeaways

Summary of Bactrim vs. Amoxicillin

Indications of Bactrim vs. Amoxicillin

Pros and Cons of Bactrim vs. Amoxicillin

Common Side Effects of Bactrim vs. Amoxicillin

Warnings of Bactrim vs. Amoxicillin

Prices with our coupons for Bactrim vs. Amoxicillin

Compare other Ear Infection and Urinary Tract Infection drugs

Browse medications

Good news for your inbox