Can You Take Ceftin If You Have A Pencillin Allergy?

In our latest question and answer, the pharmacist discusses whether or not you can take Ceftin (cefuroxime) if you have a penicillin allergy.

Mar 17, 2018

Steff asked

Can you half Ceftin tablets? What are the incidence of cross reaction to penicillin with this or Keflex.


Ceftin (cefuroxime) is a second generation cephalosporin antibiotic used in the treatment of infections including:

  • Sinus infections
  • Bronchitis
  • Ear infections
  • Bone and joint infections
  • Lower respiratory infections
  • Skin infections
  • Urinary tract infections

Ceftin (cefuroxime) is a film coated tablet.  Tablets are coated for a variety of reasons, including:

  • They are easier to swallow
  • Coatings may mask the unpleasant taste of a medication

According to Ceftin's manufacturer package insert, Ceftin should be swallowed whole due to the lasting, bitter taste of the drug.  The manufacturer recommends patients take a liquid form of the drug if swallowing the tablet whole is an issue.

Cross-Sensitivity To Cephalosporins In Patients with Penicillin Allergy

In order to discuss the possibility of cross sensitivity to cephalosporins, like Ceftin (cefuroxime) or Keflex (cephalexin), it is necessary to understand the different types of penicillin reactions:

Immediate/Accelerated Reactions (Type 1)
  • Immediate reactions usually occur within one hour of taking penicillin
  • Accelerated reactions can occur within 72 hours of penicillin dose
  • Involves penicillin-specific antibodies
  • The following symptoms can be present: Drop in blood pressure, hives, difficulty breathing, itchy rash, swelling of throat, wheezing, difficulty swallowing and nausea/vomiting
Late Reactions

Late reactions are reactions that occur after 72 hours from taking your dose. Symptoms may include:

  • Rashes
  • Joint pain
  • Itching
  • Swollen lymph nodes
  • Stevens-Johnson syndrome (uncommon)
  • Blood abnormalities.  
What Do Studies Say?

Older studies suggested cross-sentivity to cephalosporins for patients with a penicillin allergy was as high as 50%!

However, it is believed these early cephalosporins had trace amounts of penicillin in them leading to a higher incidence of allergic reactions. Also, these first generation cephalosporins', like Keflex (cephalexin), chemical structure is more similar to penicillins than second (like Ceftin), third and fourth generation cephalosporins.

Current studies believe the cross-sensitivity between cephalosporins and penicillin to be about 3% with the breakdown as follows:

  • Approximately 0.1% for patients that report a penicillin allergy that has not been confirmed by a skin test
  • Approximately 0.1% for patients that report mild reactions to penicillin
  • Approximately 2% for patients with a penicillin allergy that has been confirmed by a positive penicillin skin test

As stated above, cephalosporins that have a similar chemical structure, specifically the R-group side chains, are most likely to cause a reaction in patients with penicillin allergies.  Cephalosporins with these identical R-group side chains include cefadroxil, cefprozil, cefaclor and Keflex (cephalexin).

For patients with Type I reactions that was discussed above, cephalosporins should be used very cautiously.  First generation cephalosporins, like Keflex (cephalexin) should not be used at all. For patients with less serious reported penicillin allergies, cephalosporin drugs, like second generation Ceftin (cefuroxime), can be tried.  

But again, first generation cephalosporins, like Keflex (cephalexin), should be avoided. The American Academy of Allergy, Asthma and Immunology reports that only 10% of patients who report a penicillin allergy actually have a positive skin test for a penicillin allergy.  Any reactions experienced when taking a cephalosporin drug, like Ceftin (cefuroxime) or Keflex (cephalexin), should be reported to your doctor or other health care provider immediately.  Should symptoms of shortness of breath, swelling of the lips or throat or difficulty breathing be experienced, 911 should be called immediately.


  • Ceftin (cefuroxime) is not a tablet that should be split due to its film coating and bitter taste of the drug.
  • If the tablet cannot be swallowed whole, a liquid form of the medication should be prescribed by your doctor.  
  • Most patients with a penicillin allergy can take a second generation cephalosporin drug, like Ceftin (cefuroxime), without having a cross-sensitivity reaction.
  • First generation cephalosporins, like Keflex (cephalexin), should generally be avoided due to side chain similarity with penicillins.  Those patients who have experienced a Type I, immediate, potentially life threatening reaction to penicillin, should be given any cephalosporin very cautiously.  

Always remember that any reaction experienced while on Ceftin (cefuroxime), or drug for that matter, should immediately be reported to your doctor. 911 should be called if any breathing problems or swelling of the lips, mouth or throat occurs.  


1. Clinical Resource, Beta-Lactam Allergy: FAQs. Pharmacist's Letter/Prescriber's Letter. March 2017

Ready for a more personal experience with your meds?