Macrobid vs. Bactrim for Urinary Tract Infection: Important Differences and Potential Risks.

Key takeaways

Nitrofurantoin (Macrodantin) and sulfamethoxazole/trimethoprim (Bactrim) are both antibiotics used to treat urinary tract infections (UTIs). However, there are some differences between them. Nitrofurantoin is a nitrofuran antibiotic, while sulfamethoxazole/trimethoprim is a combination of a sulfonamide and an antifolate. Macrodantin is taken orally, typically every 6 hours for 5 to 7 days, and is available in both capsule and oral suspension forms. In contrast, sulfamethoxazole/trimethoprim is usually taken twice daily for 3 to 14 days and is available as tablets, a liquid suspension, and an injection. Nitrofurantoin has fewer drug interactions and is safe for those with sulfa allergies, but it can cause side effects like nausea and headache. Sulfamethoxazole/trimethoprim can cause side effects such as nausea, diarrhea, and rash, and it interacts with more medications, including dofetilide. Additionally, sulfamethoxazole/trimethoprim is not recommended during pregnancy, while nitrofurantoin should be avoided in the last weeks of pregnancy. Both medications have generic versions available, making them more affordable options.

Nitrofurantoin

(Macrobid)

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Sulfamethoxazole/trimethoprim

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Summary for Macrobid

Prescription only

Nitrofurantoin (Macrobid) is an antibiotic used to treat or prevent a urinary tract infection (UTI). Some side effects include nausea, headache, and gas. It can also make your urine turn dark yellow or brown. Nitrofurantoin (Macrobid) doesn't have many interactions with other medications. There's a lower-cost generic version of nitrofurantoin (Macrobid) available.

Indications for Macrobid

Treatment or prevention of urinary tract infections

Pros and Cons for Macrobid

Pros

Works well to treat and prevent UTIs
Available as both a capsule and a flavored oral suspension
Safe to take if you're allergic to other antibiotics like penicillin or sulfa medications (e.g., Bactrim, Septra (sulfamethoxazole / trimethoprim))

Cons

Might need to take up to four times a day (depending on the formulation)
Can interact with certain types of antacids, travel vaccines, and lab tests
Can harm your lungs, liver, and nerves if taken for a long period of time

Common Side Effects for Macrobid

Nausea (8%)
Headache (6%)
Gas (2%)

Warnings for Macrobid

Lung damage
Liver damage
Nerve damage (neuropathy)
Breakdown of red blood cells (hemolytic anemia)
Severe diarrhea

Summary for Bactrim

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.

Indications for Bactrim

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

Pros and Cons for Bactrim

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

Common Side Effects for Bactrim

Nausea
Vomiting
Diarrhea
Loss of appetite
Rash
Hives
Skin sensitivity to sun or light

Warnings for Bactrim

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