Clindamycin vs. Cephalexin

See how Clindamycin and Cephalexin compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Clindamycin is often chosen for serious infections and as an alternative for patients with penicillin allergies, but it carries a boxed warning for C. difficile-associated colitis.

  • Cephalexin is a first-generation cephalosporin used for common outpatient infections like strep throat, ear infections, and UTIs, and it generally causes fewer GI side effects than clindamycin.

  • Clindamycin comes in oral, IV, topical, and vaginal forms, while cephalexin is available only as an oral capsule, tablet, or liquid suspension.

Clindamycin vs. Cephalexin Drug Summary

Clindamycin

Clindamycin is a lincosamide antibiotic used for serious infections caused by anaerobic bacteria, streptococci, staphylococci, and pneumococci. It comes in oral capsules, IV/IM injection, and topical or vaginal forms, and is often chosen for patients allergic to penicillin.

Cephalexin

Cephalexin is a first-generation cephalosporin antibiotic used for common infections like strep throat, ear infections, skin infections, and UTIs. It is taken orally as a capsule, tablet, or liquid suspension, usually every 6 to 12 hours.

Clindamycin vs. Cephalexin Side Effects

Clindamycin

Most common
Diarrhea (up to 20%)
Vomiting (up to 6%)
Nausea (up to 6%)
Abdominal pain (up to 3%)

Cephalexin

Most common
Diarrhea (up to 6%)
Vomiting (up to 2%)
Nausea (up to 3%)
Abdominal pain (up to 2%)

Clindamycin vs. Cephalexin Dosage

Clindamycin

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 150 mg every 6 hours At the start
Maximum dose up to 4800 mg/day IV If needed
Dose changes 6 increases As tolerated

Cephalexin

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 25-50 mg/kg/day divided At the start
Maximum dose 1 to 4 g/day divided If needed
Dose changes 4 increases As tolerated

Clindamycin vs. Cephalexin Indications

Clindamycin

Clindamycin is FDA-approved for serious infections caused by susceptible anaerobic bacteria, as well as certain streptococcal, staphylococcal, and pneumococcal infections. It is used for lower respiratory, skin, bone, joint, and gynecological infections, and topical or vaginal forms treat acne and bacterial vaginosis. It is not effective for viral infections or most upper respiratory infections.

  • Serious anaerobic bacterial infections

  • Skin and skin structure infections

  • Bone and joint infections

  • Gynecological infections

  • Acne vulgaris (topical form)

Cephalexin

Cephalexin is FDA-approved for respiratory tract infections, ear infections, skin infections, bone infections, and genitourinary infections caused by susceptible bacteria. It is commonly prescribed for strep throat, otitis media, and uncomplicated UTIs in outpatient settings. It is not effective against anaerobic bacteria or viral illnesses.

  • Respiratory tract infections

  • Otitis media (ear infections)

  • Skin and skin structure infections

  • Bone infections

  • Genitourinary tract infections

Clindamycin vs. Cephalexin Pros and Cons

Clindamycin

Clindamycin is a versatile antibiotic available in oral, IV, topical, and vaginal forms, making it useful across many infection types. It's often selected for patients with penicillin allergies but carries a boxed warning for C. difficile colitis, so it's typically reserved for infections where other options aren't suitable.

Pros

  • Effective against anaerobic bacteria

  • Preferred option for penicillin allergy

  • Available in oral, IV, topical, and vaginal forms

  • Reaches bone and joint tissue well

Cons

  • Boxed warning for C. diff colitis

  • Requires dosing every 6 hours orally

  • Must be taken with plenty of water

  • Higher reported rates of GI side effects

Cephalexin

Cephalexin is a well-established, generic-only antibiotic widely used for common outpatient infections like strep throat and UTIs. It generally causes fewer GI disturbances than clindamycin, but cross-reactivity concerns exist for patients with cephalosporin or penicillin allergies.

Pros

  • Only available as low-cost generic

  • Simple twice-daily adult dosing

  • Long history of use for common infections

  • Generally fewer GI side effects reported

Cons

  • Cross-reactivity risk with penicillin allergy

  • Not effective against anaerobic bacteria

  • Dose adjustment needed in kidney impairment

  • Not used for serious systemic infections

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