Macrobid vs. Bactrim
See how Macrobid and Bactrim compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Macrobid is a narrow-spectrum option built specifically for uncomplicated bladder infections, while Bactrim treats a much wider range of infections including bronchitis, ear infections, and traveler's diarrhea.
Bactrim typically costs far less than Macrobid, but it carries a higher risk of severe skin reactions such as Stevens-Johnson syndrome.
Macrobid cannot be used safely if kidney function is reduced, while Bactrim requires caution with potassium levels and folate deficiency.
Macrobid vs. Bactrim Drug Summary
Macrobid
Macrobid is a urinary anti-infective in the nitrofuran class, used to treat uncomplicated bladder infections caused by E. coli or S. saprophyticus. It is taken as an oral capsule every 12 hours for seven days and concentrates in the urine rather than the bloodstream.
Bactrim
Bactrim combines sulfamethoxazole and trimethoprim, which block two sequential steps in bacterial folate synthesis. It treats urinary tract infections, pneumonia, bronchitis, traveler's diarrhea, and other bacterial infections. It comes as a tablet, liquid, or injection, usually dosed every 12 hours.
Macrobid vs. Bactrim Side Effects
Macrobid
Bactrim
Macrobid vs. Bactrim Dosage
Macrobid
Bactrim
| STAGE | DOSE | WHEN |
| Starting dose | 100 mg every 12 hours | Days 1-7 |
| Maximum dose | 100 mg every 12 hours | Same as starting |
| Dose changes | None | Fixed dose |
| STAGE | DOSE | WHEN |
| Starting dose | 800 mg/160 mg every 12h | At the start |
| Maximum dose | 8-10 mg/kg/day TMP q6-12h | If needed |
| Dose changes | 3 increases | As tolerated |
Macrobid
| STAGE | DOSE | WHEN |
| Starting dose | 100 mg every 12 hours | Days 1-7 |
| Maximum dose | 100 mg every 12 hours | Same as starting |
| Dose changes | None | Fixed dose |
Bactrim
| STAGE | DOSE | WHEN |
| Starting dose | 800 mg/160 mg every 12h | At the start |
| Maximum dose | 8-10 mg/kg/day TMP q6-12h | If needed |
| Dose changes | 3 increases | As tolerated |
Macrobid vs. Bactrim Indications
Macrobid
Macrobid is FDA-approved only for uncomplicated bladder infections caused by susceptible bacteria, not for kidney infections or infections that have spread beyond the bladder. Doctors sometimes prescribe it off-label at a lower dose for long-term prevention of recurrent UTIs.
Treats acute uncomplicated cystitis (E. coli, S. saprophyticus)
Off-label: low-dose prophylaxis for recurrent UTIs
Not approved for pyelonephritis or kidney infections
Not approved for children under 12 or infants under 1 month
Bactrim
Bactrim is FDA-approved for a wide range of infections beyond UTIs, including Pneumocystis pneumonia, shigellosis, ear infections in children, and traveler's diarrhea. It is also used off-label for certain skin infections caused by MRSA.
Treats UTIs, PCP, shigellosis, otitis media, and more
Off-label: MRSA skin and soft tissue infections
Off-label: Stenotrophomonas maltophilia infections
Not approved for strep throat (Group A)
Macrobid vs. Bactrim Pros and Cons
Macrobid
Macrobid's narrow focus on the urinary tract makes it a reliable, low-disruption option for straightforward bladder infections, and resistance remains low despite decades of use. It is not an option for anyone with reduced kidney function, and it costs more out of pocket than Bactrim.
Pros
Narrow spectrum lowers risk of disrupting gut bacteria
Remains effective against E. coli despite decades of use
Short 7-day course for most UTIs
Cons
Not safe if kidney function is reduced (CrCl under 60)
Risk of lung damage with long-term use
Not approved for children under 12
Bactrim
Bactrim's broader reach lets it treat infections beyond the bladder, including some that spread to the kidneys or bloodstream, and it is one of the least expensive antibiotics available. It carries a higher risk of serious skin reactions and drug interactions than more narrowly targeted options.
Pros
Treats many infection types beyond UTIs
Effective for kidney infections since it reaches the bloodstream
Roughly $10 to $30 per month without insurance, less than Macrobid
Cons
Higher risk of severe skin reactions (Stevens-Johnson syndrome)
Contraindicated with folate deficiency anemia
More drug interactions due to broader systemic effects
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