Cipro vs. Keflex

See how Cipro and Keflex compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Cipro can clear an uncomplicated UTI in as few as 3 days, but its boxed warnings for tendon rupture and nerve damage limit it to cases without safer options.

  • Keflex has a milder safety profile with no boxed warnings, but it does not cover Pseudomonas and usually needs 7 to 14 days of treatment for a UTI.

  • Both are taken by mouth, but Cipro is typically dosed twice daily while Keflex may be needed every 6 to 12 hours depending on the infection.

Cipro vs. Keflex Drug Summary

Cipro

Cipro (ciprofloxacin) is a fluoroquinolone antibiotic used for urinary tract infections and several other bacterial infections. It is taken by mouth, typically every 12 hours, with the dose and length of treatment set by how severe the infection is.

Keflex

Keflex (cephalexin) is a first-generation cephalosporin antibiotic used for urinary tract infections along with skin, respiratory, and bone infections. It is taken by mouth, typically every 6 to 12 hours, with dosing based on the type and severity of infection.

Cipro vs. Keflex Side Effects

Cipro

Most common
Vomiting (4.8%)
Diarrhea (4.8%)
Nausea (2.7%)
Rash (1.8%)

Keflex

Most common
Vomiting (rate not quantified in current label)
Diarrhea (rate not quantified in current label)
Nausea (rate not quantified in current label)
Dyspepsia (rate not quantified in current label)

Cipro vs. Keflex Dosage

Cipro

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 250 mg every 12 hours At the start
Maximum dose 750 mg every 12 hours If needed
Dose changes 2 increases As tolerated

Keflex

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 250 mg every 6 hours At the start
Maximum dose 25-50 mg/kg/day divided If needed
Dose changes 3 increases As tolerated

Cipro vs. Keflex Indications

Cipro

Cipro is FDA-approved for uncomplicated and complicated urinary tract infections, including pyelonephritis caused by E. coli and other gram-negative bacteria. It also treats skin, bone and joint, respiratory, and intra-abdominal infections, plus certain cases of infectious diarrhea and typhoid fever.

  • Uncomplicated UTI (cystitis)

  • Complicated UTI and pyelonephritis

  • Skin and skin structure infections

  • Bone and joint infections

  • Infectious diarrhea and typhoid fever

Keflex

Keflex is FDA-approved for genitourinary tract infections, including UTIs, along with respiratory tract infections, otitis media, and skin and skin structure infections. It is also approved for bone infections but is not effective against Pseudomonas or Acinetobacter species.

  • Urinary tract infections

  • Respiratory tract infections

  • Otitis media

  • Skin and skin structure infections

  • Bone infections

Cipro vs. Keflex Pros and Cons

Cipro

Cipro is a fluoroquinolone that reaches high concentrations in urine and works quickly against many gram-negative bacteria, including Pseudomonas. That broad coverage comes with boxed warnings that push it toward infections without safer alternative treatments.

Pros

  • Covers Pseudomonas and other tough gram-negative bacteria

  • Only 3 days of treatment for an uncomplicated UTI

  • Available in extended-release and IV forms for severe infections

  • Specifically FDA-approved for pyelonephritis

Cons

  • Boxed warnings for tendon rupture, nerve damage, and aortic issues

  • Rising bacterial resistance limits first-line use for simple UTIs

  • Must be timed away from dairy, antacids, and mineral supplements

  • FDA advises reserving it when other options aren't suitable

Keflex

Keflex is an older cephalosporin with a well-documented safety record and fewer serious warnings than fluoroquinolones. It covers many common UTI pathogens but not Pseudomonas, and its treatment courses tend to run longer.

Pros

  • No boxed warnings on the label

  • Long track record of use since 1971

  • Fewer significant drug interactions to manage

  • Often preferred when fluoroquinolones aren't appropriate

Cons

  • Not effective against Pseudomonas or Acinetobacter

  • Dosed as often as every 6 hours for some infections

  • UTI treatment often runs 7 to 14 days instead of 3

  • Carries C. diff diarrhea and seizure risks in kidney impairment

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