Doxycycline vs. Cephalexin

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

Key Takeaways

  • Doxycycline covers a broader range of infections, including tick-borne illness and sexually transmitted infections, while cephalexin mainly treats skin, respiratory, ear, bone, and urinary infections.

  • Cephalexin is typically taken two to four times a day, while doxycycline is usually taken once or twice daily.

  • Doxycycline causes sun sensitivity and isn't safe for young children or during pregnancy, while cephalexin carries a cross-reaction risk for people with penicillin allergies.

Doxycycline vs. Cephalexin Drug Summary

Doxycycline

Doxycycline is a tetracycline-class antibacterial used to treat a wide range of bacterial and rickettsial infections, including respiratory infections, sexually transmitted infections, and tick-borne illnesses. It comes as an oral capsule, tablet, or suspension, usually taken once or twice a day.

Cephalexin

Cephalexin is a first-generation cephalosporin antibacterial used to treat common bacterial infections of the skin, respiratory tract, ears, bones, and urinary tract. It comes as an oral capsule, tablet, or suspension, typically taken two to four times a day.

Doxycycline vs. Cephalexin Side Effects

Doxycycline

Most common
Vomiting (rate not quantified in labeling)
Nausea (rate not quantified in labeling)
Diarrhea (rate not quantified in labeling)
Rash (rate not quantified in labeling)

Cephalexin

Most common
Vomiting (rate not specified in FDA label)
Nausea (rate not specified in FDA label)
Diarrhea (rate not specified in FDA label)
Dyspepsia (rate not specified in FDA label)

Doxycycline vs. Cephalexin Dosage

Doxycycline

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 200 mg total Day 1
Maximum dose 100 mg twice daily If needed
Dose changes 3 increases Every day

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

Doxycycline vs. Cephalexin Indications

Doxycycline

Doxycycline treats a wide range of bacterial infections, including tick-borne illnesses like Rocky Mountain spotted fever, sexually transmitted infections, and respiratory infections. It's also FDA-approved for anthrax exposure and malaria prevention, and used off-label for Lyme disease and acne.

  • Rocky Mountain spotted fever and other rickettsial infections

  • Sexually transmitted infections including chlamydia and gonorrhea

  • Respiratory tract infections

  • Anthrax post-exposure prophylaxis

  • Malaria prevention

Cephalexin

Cephalexin treats common bacterial infections including strep throat, ear infections, skin infections, and urinary tract infections. It's also approved for certain bone infections and used off-label for acne, but covers a narrower range of infection types than doxycycline.

  • Respiratory tract infections (strep throat)

  • Ear infections (otitis media)

  • Skin and skin structure infections

  • Bone infections

  • Urinary tract and prostate infections

Doxycycline vs. Cephalexin Pros and Cons

Doxycycline

Doxycycline covers more infection types than cephalexin, including atypical bacteria that cause tick-borne illness, chlamydia, and traveler's diarrhea. It's usually dosed once or twice daily, but it requires sun protection and isn't safe for young children or during pregnancy.

Pros

  • Effective against atypical bacteria like rickettsia and chlamydia

  • Also approved for malaria prevention and anthrax exposure

  • Once or twice daily dosing is easier to stick with

  • Long-standing generic with wide availability

Cons

  • Causes photosensitivity, requiring sun avoidance

  • Not safe for children under 8 or during pregnancy

  • Can cause esophageal irritation if not taken with fluids

  • Boxed warnings for tooth discoloration and fetal harm

Cephalexin

Cephalexin is a reliable first choice for common skin, respiratory, ear, and urinary infections caused by susceptible strep and staph bacteria. It's considered safe in pregnancy and young children, but it must be taken more often and doesn't work against atypical bacteria.

Pros

  • Considered safe during pregnancy and in young children

  • No sun sensitivity or tooth discoloration concerns

  • Well-established for skin, ear, and urinary infections

  • Widely available as an inexpensive generic

Cons

  • Must be taken up to four times daily

  • Not effective against atypical bacteria like chlamydia or rickettsia

  • Cross-reactivity risk in people with penicillin allergy

  • Requires dose adjustment in kidney impairment

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