What is equivalent to Keflex? A Guide to Cephalexin Alternatives

October 12, 2025 •

3 min read

In 2020, cephalexin, the generic form of Keflex, was prescribed to approximately 4.2 million people in the United States. This guide explores the question: what is equivalent to Keflex?, detailing generic options, same-class alternatives, and other antibiotic choices.

Quick Summary

An overview of medications equivalent to Keflex (cephalexin). Covers direct generic equivalents, other cephalosporin antibiotics, and alternatives from different classes like penicillins for treating various bacterial infections.

Key Points

Direct Equivalent: The most direct equivalent to Keflex is its generic form, cephalexin; they are medically identical. The brand name Keflex is no longer marketed in the US.
Same-Class Alternatives: Other first-generation cephalosporins like Cefadroxil offer a similar spectrum of activity. Later generations like Cefdinir (oral) and Ceftriaxone (injectable) offer broader coverage.
Cross-Class Alternatives: For those with allergies or resistance, alternatives include penicillins (Amoxicillin), macrolides (Azithromycin), and tetracyclines (Doxycycline).
Common Infections Treated: Keflex is used for bacterial infections of the skin, urinary tract, respiratory system, bones, and ears.
Mechanism of Action: As a cephalosporin antibiotic, Keflex works by disrupting the formation of the bacterial cell wall, which kills the bacteria.
Professional Consultation is Essential: Never switch antibiotics without a doctor's guidance, as the correct choice depends on the specific bacteria, infection type, and patient allergies.

Understanding Keflex (Cephalexin)

Keflex is the brand name for the generic drug cephalexin. It is a first-generation cephalosporin antibiotic used to treat bacterial infections by interfering with bacterial cell wall formation. Cephalexin is available orally in capsules, tablets, and liquid suspension.

It is prescribed for various bacterial infections, including respiratory, urinary tract, skin, bone, and ear infections. Keflex is ineffective against viruses.

Direct Equivalents: Generic Cephalexin

The direct equivalent to brand-name Keflex is generic cephalexin. In the U.S., only generic cephalexin is currently available, as the brand name Keflex is discontinued. Generic cephalexin has the same active ingredient, efficacy, safety, and dosing as Keflex, with a typical lower cost. Other past brand names include Cephadex and Phexin.

Same-Class Alternatives: Other Cephalosporins

Cephalosporins are classified by generations based on their activity spectrum. First-generation cephalosporins like Keflex primarily target gram-positive bacteria.

First-Generation Cephalosporins

These share a similar spectrum to Keflex:

Cefadroxil (Duricef): Similar to cephalexin, potentially allowing for less frequent dosing.
Cefazolin (Ancef): An injectable first-generation cephalosporin used in hospitals for severe infections or surgical prevention.

Later-Generation Cephalosporins

Later generations offer broader gram-negative coverage.

Second-Generation (e.g., Cefaclor, Cefprozil, Cefuroxime): Improved activity against some respiratory pathogens. Cefuroxime is also used for conditions like Lyme disease.
Third-Generation (e.g., Cefdinir, Ceftriaxone): Offer broader coverage. Cefdinir is an oral option for skin infections. Ceftriaxone (Rocephin) is an injectable, broad-spectrum antibiotic for severe infections like meningitis.

Alternatives from Different Antibiotic Classes

For patients with allergies to cephalosporins or penicillin, or for resistant infections, other antibiotic classes may be used.

Penicillins (e.g., Amoxicillin, Augmentin): Amoxicillin is a penicillin that, like cephalexin, inhibits bacterial cell walls. Augmentin combines amoxicillin with clavulanate to counter resistance. These are used for respiratory, ear, and skin infections.
Macrolides (e.g., Azithromycin, Erythromycin): Used for respiratory and skin infections and are an option for penicillin allergies.
Tetracyclines (e.g., Doxycycline): Effective for skin, respiratory, and tick-borne diseases; an alternative for penicillin or cephalosporin allergies.
Sulfonamides (e.g., Bactrim): Used for UTIs, bronchitis, and traveler's diarrhea.
Fluoroquinolones (e.g., Ciprofloxacin, Levofloxacin): Broad-spectrum antibiotics for various infections, though sometimes reserved due to side effects.

Comparison of Common Keflex Alternatives


Medication	Class	Common Uses	Key Differences from Keflex
Cephalexin (Keflex)	1st-Gen Cephalosporin	Skin, UTIs, respiratory, bone, ear infections	Baseline for comparison.
Amoxicillin	Penicillin	Ear, respiratory, UTIs; endocarditis prevention	Different class (penicillin); risk for those with penicillin allergy.
Augmentin	Penicillin Combo	Same as amoxicillin, plus resistant bacteria	Contains clavulanate to combat resistance; higher rate of diarrhea.
Cefdinir (Omnicef)	3rd-Gen Cephalosporin	Skin, respiratory infections	Broader gram-negative coverage than Keflex.
Doxycycline	Tetracycline	Skin (acne), respiratory, STIs, tick-borne diseases	Different mechanism; cannot be used in pregnancy or young children.
Azithromycin (Zithromax)	Macrolide	Respiratory, skin, STIs	Common alternative for penicillin-allergic patients.

Important Considerations When Switching

It is crucial to always consult a healthcare professional before changing antibiotics. The appropriate antibiotic choice depends on factors including the specific bacteria, infection site and severity, patient allergies, potential drug interactions (e.g., Keflex with metformin), and local resistance patterns. Improper substitution can lead to treatment failure and contribute to antibiotic resistance.

Conclusion

The most direct equivalent to brand-name Keflex is generic cephalexin. However, several therapeutic alternatives are available, including other cephalosporins like cefadroxil and cefdinir, and antibiotics from different classes such as amoxicillin, doxycycline, and azithromycin. The best alternative is determined by the specific infection and patient factors. A qualified healthcare provider must make any decision to switch antibiotics to ensure safe and effective treatment.

For further reading on antibiotic classifications, you can visit the American Academy of Family Physicians.

Frequently Asked Questions

Yes, they are medically equivalent. Keflex was the brand name for the antibiotic cephalexin. Cephalexin is the generic name for the active drug. Although the brand name Keflex is discontinued, the generic cephalexin is widely available.

Amoxicillin is a common alternative to Keflex but belongs to a different class (penicillins). The choice depends on the infection type and your allergy history. If you have a penicillin allergy, you may not be able to take amoxicillin. Always consult a doctor before making any substitution.

If you are allergic to Keflex (a cephalosporin), your doctor might prescribe an antibiotic from a different class, such as a macrolide (like azithromycin), a tetracycline (like doxycycline), or a fluoroquinolone. The choice depends on your specific infection and allergy history.

Both are cephalosporin antibiotics, but Keflex (cephalexin) is a first-generation and Cefdinir is a third-generation. Cefdinir generally has a broader spectrum of activity against gram-negative bacteria compared to Keflex.

Keflex (cephalexin) is used to treat a variety of bacterial infections, including those affecting the skin, bones, ears, respiratory tract, and urinary tract.

While some natural substances like garlic, honey, and oregano have shown antimicrobial properties in studies, they are not regulated or proven equivalents to prescription antibiotics like Keflex. You should always consult a healthcare provider for a bacterial infection, as untreated infections can become serious.

Yes, generic medications like cephalexin are typically less expensive than their brand-name counterparts. The brand-name Keflex is no longer on the market in the US.