Bactrim vs. Macrobid
See how Bactrim and Macrobid compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Bactrim treats a broader range of infections, including UTIs, respiratory infections, and PCP, while Macrobid is approved only for uncomplicated urinary tract infections.
Bactrim carries a risk of serious skin reactions and is unsafe in infants or people with G6PD deficiency, while Macrobid carries risks of lung and liver toxicity with long-term use.
Bactrim is typically far less expensive than Macrobid, but the right choice depends on where the infection is and what's causing it.
Bactrim vs. Macrobid Drug Summary
Bactrim
Bactrim (sulfamethoxazole/trimethoprim) is a combination sulfonamide antibiotic that blocks two sequential steps in bacterial folate production. It's taken as an oral tablet, liquid, or IV infusion, usually every 12 hours, for infections like UTIs, bronchitis, and Pneumocystis pneumonia.
Macrobid
Macrobid (nitrofurantoin) is a urinary anti-infective that concentrates in urine rather than the bloodstream. It's taken as an oral capsule twice daily for 7 days, specifically for uncomplicated bladder infections.
Bactrim vs. Macrobid Side Effects
Bactrim
Macrobid
Bactrim vs. Macrobid Dosage
Bactrim
Macrobid
| STAGE | DOSE | WHEN |
| Starting dose | 800 mg/160 mg q12h | At the start |
| Maximum dose | 8-10 mg/kg/day | If needed |
| Dose changes | 3 increases | As tolerated |
| 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 q12h | At the start |
| Maximum dose | 8-10 mg/kg/day | 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 vs. Macrobid Indications
Bactrim
Bactrim treats a broad range of bacterial infections, from urinary tract infections to Pneumocystis pneumonia. It combines two antibiotics that block sequential steps in bacterial folate production, which helps limit resistance.
Pneumocystis pneumonia (PCP) treatment and prevention
Shigellosis
Urinary tract infections
Acute otitis media in children
Macrobid
Macrobid is FDA-approved only for acute, uncomplicated urinary tract infections caused by E. coli or S. saprophyticus. It concentrates in urine rather than the bloodstream, so it isn't effective for infections outside the bladder.
Acute uncomplicated UTIs (cystitis)
Caused by E. coli or S. saprophyticus
Off-label: long-term prevention of recurrent UTIs
Not used for kidney infections (pyelonephritis)
Bactrim vs. Macrobid Pros and Cons
Bactrim
Bactrim is a low-cost combination antibiotic with FDA approval for several infection types, including UTIs, respiratory infections, and PCP prevention. It's widely stocked and generally covered by insurance without much hassle.
Pros
Covers a wide range of infections beyond the urinary tract
Used for both treatment and prevention of PCP in immunocompromised patients
Available as tablet, liquid, and IV formulations
Cons
Carries a risk of severe skin reactions (SJS/TEN)
Contraindicated in infants under 2 months old
Not safe in G6PD deficiency due to hemolytic anemia risk
Should be avoided during pregnancy and breastfeeding
Macrobid
Macrobid is a targeted urinary antibiotic that stays concentrated in the bladder, so it works well for uncomplicated UTIs but not for infections elsewhere in the body. It costs more than many older antibiotics and may need prior authorization from some insurers.
Pros
Remains reliably effective against E. coli despite decades of use
Stays concentrated in urine with minimal systemic absorption
Used off-label for long-term prevention of recurrent UTIs
Cons
Not approved for kidney infections or systemic infections
Contraindicated in significant kidney impairment
Long-term use linked to lung and liver toxicity
Costs more, roughly $80 to $200 per month without insurance
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