Is Cefazolin better than Cephalexin? (3+ differences)

In this article, we will discuss whether cefazolin is better than Cephalexin or vice versa. Furthermore, we’ll find out the basic differences between them, how they work, which one has a broader spectrum against bacterial infections, what research suggests on this, their safe and effective use and if there are any differences in cost and accessibility of Cefazolin and Cephalexin. 

Is Cefazolin better than Cephalexin?

There is no such report that claims that Cefazolin is inherently better than Cephalexin. Rather their appropriateness depends on the specific circumstances of the infection, the individual’s specific condition and how the individual responds to the medication. (1)

Both Cefazolin and Cephalexin belong to the class of antibiotics called cephalosporins. Both are widely used for the treatment of a broad range of bacterial infections which may include respiratory tract infections, skin and soft tissue infections and UTIs among others. Both of these antibiotics exert their effects by inhibiting the synthesis of bacterial cell walls thus, making the bacteria inactive or killed. (1,2)

The choice between Cefazolin and Cephalexin depends on the severity and type of infections. Cefazolin is often given in emergencies to hospitalized patients whereas Cephalexin is prescribed to outpatients. 

What does research suggest?

According to a research study, scientists at the National Taiwan University Hospital experimented to determine the effectiveness of four types of antibiotics belonging to the cephalosporin class namely, Cefazolin, Cephalexin, Cephaloridine and Cephalothin. They wanted to see how well these antibiotics fight against bacteria. (3)

They tested 330 bacterial samples using the agar plate dilution method and found that Cephaloridine, Cefazolin and Cephalothin were able to suppress more than 90% of Staphylococcus aureus at concentrations of 3.13 micrograms/ml or less whereas, Cephalexin could only suppress about 49.1%. (3)

They also found that Cefazolin turned out to be most effective against certain bacteria like E. coli and Klebsiella pneumonia which are not very sensitive to other drugs of cephalosporin class. (3)

The results showed that Cefazolin, in particular, was found to be more powerful than other tested antibiotics. 

How does Cefazolin differ from Cephalexin?

Cefazolin and Cephalexin are antibiotics of the same class however, they differ in formulations, availability of dosage strengths and to some extent spectrum of activity. Here are some key differences discussed below in the table: (1,2)



Dosage strength

Spectrum of activity

Brand names

Cefazolin Injectable form (intravenous or intramuscular)
  • Adult dosage: 1-2 grams every 8 hours.
  • Pediatric dosage: weight-based.
  • Broader spectrum of activity.
  • Very effective against Gram +ve and moderately effective against Gram -ve. 




Cephalexin Oral form (tablets or capsules)
  • Adult dose: 250 mg-500 mg every 6 to 12 hours.
  • Pediatric dosage: weight-based.
  • Spectrum may not be as broad as Cefazolin.
  • Effective against most Gram +ve and certain Gram -ve bacteria. 





How does Cefazolin differ in cost and accessibility from Cephalexin?

The cost and accessibility of medications including Cefazolin and Cephalexin can vary based on different factors like geographic location, insurance coverage, healthcare systems and the specific formulations prescribed. (5)

If we talk about cost, Cefazolin in its injectable form which is mainly used in hospital settings, may be more expensive than oral antibiotics like Cephalexin and its accessibility is often limited to hospitals or clinics. It is not prescribed for at-home use. (4)

While Cephalexin on the other hand, available in oral forms such as tablets and capsules tends to be more cost-effective than injectable antibiotics. Its generic versions are also often available which further cuts down the cost. Generic versions of drugs are more affordable compared to branded drugs. (5)

Patients are typically advised to consult their healthcare providers or local pharmacies and insurance providers if they’re concerned about the cost and accessibility of medications and to get accurate and up-to-date information. (5)

How to ensure the safe use of Cefazolin and Cephalexin?

It’s important to ensure the safe and effective use of medications including Cefazolin and Cephalexin to get the intended therapeutic outcome. Take these antibiotics only if prescribed by your healthcare provider and strictly follow the dosage regimen. Check the drug label for the expiry date before start taking as expired Cephalexin or Cefazolin may have altered chemical integrity. (1)

Do not alter the dose or stop taking antibiotics mid-treatment on your own even if the symptoms get improved because failure to complete the course may result in antibiotic resistance. Inform your doctor about your past and current medical condition including any pre-existing health condition or known allergies, especially to cephalosporin and penicillin. (1,2)

Follow the administration instructions carefully as guided by your doctor. In the case of oral Cephalexin, you can take it with or without food and for injectable forms like Cefazolin, adhere to the administration techniques. It is usually administered in a hospital setting by a professional. (2)

It’s important to keep in mind that adequate hydration is crucial, especially with oral antibiotics to support kidney function and drug elimination so drink a sufficient amount of water. Also, do avoid the consumption of alcohol while you’re on antibiotic course as it may cause interaction with the drug and increase the risk of side effects. (1,2)

To summarize, I would say that both Cefazolin and Cephalexin are not comparable in terms of which one is better as both have their great therapeutic and safety profiles. Both are effective and almost bioequivalent, however, there are some basic differences between them which I have discussed in this concise article.

You must be mindful enough to not take these antibiotics together as they will cause interaction and exacerbate the risk of potential side effects that are generally associated with cephalosporins, particularly in high doses. 

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