Cephalexin (Keftab) vs Common Antibiotic Alternatives: Detailed Comparison

Quick takeaways

• Cephalexin (Keftab) is a first‑generation cephalosporin that works best for skin, bone and uncomplicated urinary infections.
• Amoxicillin, azithromycin and doxycycline cover many of the same bugs but differ in dosing frequency and side‑effect profile.
• Allergy to penicillin often means cephalexin is safe; however, severe cephalosporin cross‑reactivity can occur.
• Cost varies: generic cephalexin and amoxicillin are usually under $10 for a typical course, while azithromycin and clindamycin tend to be pricier.
• Choose an alternative when the infection is caused by atypical bacteria, when resistance to cephalosporins is known, or when a once‑daily regimen is needed.

What is Cephalexin (Keftab)?

Cephalexin is a first‑generation oral cephalosporin antibiotic marketed in many countries under the brand name Keftab. First approved in the 1970s, it remains a go‑to drug for uncomplicated skin, bone and urinary tract infections caused by Gram‑positive bacteria such as Staphylococcus aureus (non‑MRSA) and Streptococcus pyogenes. Typical adult dosing is 250‑500mg every 6hours for 7‑10days, with pediatric doses adjusted by weight.

How Cephalexin Works

The drug interferes with bacterial cell‑wall synthesis by binding to penicillin‑binding proteins. This action is bactericidal, meaning it kills susceptible organisms rather than merely stopping growth. Its spectrum is strongest against Gram‑positive cocci; it has modest activity against some Gram‑negative rods like Escherichia coli. Because it is not absorbed well into the central nervous system, it’s not a first choice for meningitis.

Key Factors to Compare Antibiotics

When you’re weighing cephalexin against other oral options, look at these six criteria:

1. Microbial coverage - which bacteria are reliably killed?
2. Resistance patterns - local susceptibility data from health agencies.
3. Dosage convenience - number of pills per day and need for food.
4. Side‑effect profile - GI upset, allergic reactions, C.difficile risk.
5. Drug interactions - especially with common chronic medicines.
6. Cost & insurance - out‑of‑pocket price for a typical 7‑day course.

Side‑by‑Side Comparison Table

*Prices reflect average retail cost for a generic version in the United States in September2025.

When Cephalexin Is the Right Choice

If the infection is confirmed or strongly suspected to involve susceptible Gram‑positive organisms-think uncomplicated cellulitis, simple bone infection after a fracture, or a lower urinary tract infection in a patient without recent antibiotic exposure-cephalexin often wins on cost and safety. Its four‑times‑daily schedule can be a hurdle, but many patients tolerate it well when taken with meals.

Scenarios Where Alternatives Shine

Below are common clinical gray zones and the drug that usually fits better:

• Penicillin allergy: If the patient has a documented IgE‑mediated penicillin reaction, Azithromycin or Doxycycline provide safe oral coverage for many respiratory pathogens.
• Atypical bacteria (e.g., Mycoplasma pneumoniae or Chlamydia trachomatis): Azithromycin is the go‑to because cephalexin lacks activity.
• MRSA suspicion: For skin infections where MRSA is a concern, Clindamycin or trimethoprim‑sulfamethoxazole are more reliable.
• Convenient dosing: Travelers or busy professionals often prefer the once‑daily regimen of azithromycin or the twice‑daily plan of doxycycline.
• Renal impairment: Cephalexin is cleared renally; dosage reduction is needed in severe kidney disease. Doxycycline, which is largely hepatically cleared, can be safer in that setting.

Safety Profile and Drug Interactions

Cephalexin’s most common complaints are mild GI upset and a transient rash. It rarely triggers severe allergic reactions, but cross‑reactivity with penicillins is estimated at 2‑5%. Patients on oral anticoagulants may need INR monitoring because cephalosporins can potentiate warfarin. Clindamycin carries a higher risk of C.difficile colitis, while Azithromycin can prolong the QT interval, especially when combined with other arrhythmogenic meds.

Pricing Trends in 2025

Generic manufacturing has kept the price of cephalexin and amoxicillin under $12 for a typical course. Azithromycin’s price dropped modestly after its patent expired in 2022, but it still averages $17‑$20 due to higher demand. Clindamycin remains the most expensive of the group because many formulations are brand‑only. Insurance formularies usually place cephalexin and amoxicillin in the preferred tier, while azithromycin and clindamycin often require prior authorization.

Quick Decision Guide

Use the following three‑question flow to land on the best oral agent:

1. Is the likely pathogen a Gram‑positive cocci that is susceptible to first‑generation cephalosporins? Yes → Cephalexin.
2. Is the patient allergic to penicillins or cephalosporins? Yes → Azithromycin or Doxycycline (based on infection site).
3. Is MRSA or an atypical organism a concern? Yes → Clindamycin or Trimethoprim‑sulfamethoxazole.

When none of the above apply, amoxicillin often offers a balance of coverage, dosing convenience, and low cost.

Bottom Line

Cephalexin (Keftab) remains a solid, affordable choice for many routine infections, but it isn’t a universal solution. By weighing microbial coverage, resistance trends, dosing ease, side‑effects, and price, you can pick an alternative that aligns with the specific infection and patient circumstances.