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Doctor insights on: I Am Allergic To Penicillin Can I Take Cephalexin

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I am allergic to penicillin is it safe to take cephalexin for infection in the urine.

I am allergic to penicillin is it safe to take cephalexin for infection in the urine.

Yes: Unless you had an anaphylactic reaction to penicillin (major breathing problems) there is little risk to trying cephalexin. ...Read more

Dr. Adam Lewis
289 Doctors shared insights

Keftabs (Definition)

Keftabs is a first generation cephalosporin which is a kind of cephalosporin type drug (anti-bacterial ...Read more


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Is it possible for you to take cephalexin if you r allergic to penicillins?

Is it possible for you to take cephalexin if you r allergic to penicillins?

Yes: Cross reactivity between the two classes are low so Cephalexin is not contraindicated in penicillin allergy patients. You should have your prescribing physician to follow you for any signs of reactions and get proper treatment. ...Read more

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Can I take cephalexin if I am highly allergic to penicillin? I have not taken penicillin since I was very young. Reaction of hives convulsions

Can I take cephalexin if I am highly allergic to penicillin? I have not taken penicillin since I was very young. Reaction of hives convulsions

Penicillin allergy: You have what is known as an immediate hypersensitivity reaction to penicillin derivatives and should never be given one, since this is life-threatening. There is said to be cross-hypersensitivity reactions to cephalosporins in 5% of pen allergic persons, and 0.1% of these have a severe reaction. My advice would be not to take a cephalosporin antibiotic unless there was no alternative. ...Read more

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Allergic to penicillin can I take keflex?

Likely, not certain: The majority of people who are told they are allergic to penicillin are not actually so (they get rashes for other reasons, e.g.). Of those that are allergic, about 70% or more will lose the allergy after about 10 years. If you are still allergic, there is about a 10% chance of cross-reaction to 1st-gen cephalosporins like keflex. An allergist can perform testing to judge your risk for a reaction. ...Read more

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I'm allergic to penicillin, can I take keflex?

I'm allergic to penicillin, can I take keflex?

Maybe: Penicillins (like amoxil) & cephalosporins (like keflex) are both beta-lactam antibiotics named because of their ringed chemical structure. Allergy to penicillins is sometimes directed against this ring, and an allergic reaction may also occur if a similar antibiotic is taken. It is estimated that about 10% of penicillin-allergic patients are also allergic to cephalosporins like keflex. ...Read more

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If I'm allergic to penicillin is it safe to take keflex pulvales?

If I'm allergic to penicillin is it safe to take keflex pulvales?

No: If you are truly allergic to penicillin, you should avoid all penicillin derivatives and the first generation cephalosporins. Keflex is a first gen. Cephalosporin and may cross react with penicillin. See a board certified allergist to help you determine if penicillin is a true allergy for you. ...Read more

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Is it a bad idea for someone allergic to penicillin safely take keflex, a cephalosporin?

Yes: Cephalexin (keflex) is a first generation cephalosporin and a very close cousin to penicillin. Though it is not 100% true that all penicillin allergic individuals are also allergic to cephalexin, there is a high likelihood of that happening. ...Read more

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I m allergic to penicillin keflex azithromiacin my daughter has scarlet fever and I m worried about what I can take if I get it?

I m allergic to penicillin keflex azithromiacin my daughter has scarlet fever and I m worried about what I can take if I get it?

Don't panic: Scarlet fever is an acute febrile illness, primarily affecting children, caused by group a beta-hemolytic streptococci. Clinical manifestations include fever, sore throat, and fine sand-paper like rash caused by a toxin produced by the strep. Although penicillins are antibiotics of choice, there are other antibiotics that are effective. Your doctor will know. A throat culture is helpful. ...Read more

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I started taking cephalexin. As I have had mild allergic reaction to penicillin, should I expect serious allergic reactions to this medicatiion?

I started taking cephalexin. As I have had mild allergic reaction to penicillin, should I expect serious allergic reactions to this medicatiion?

Mostly not: The incidence of cephalexin allergy in patients with penicillin allergy is in the single digit % and likely not much different from patient without a history of penicillin allergy. However if you had a severe anaphylactic reaction to penicillin, I would suggest an allergy consult just to be safe. ...Read more

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If I got an allergic reaction from cephalexin, does that mean I am also allergic to penicillin?

If I got an allergic reaction from cephalexin, does that mean I am also allergic to penicillin?

No: There is indeed crossreactivity, but:
-if you are allergic to cephalosporins like cephalexin, and have had penicillin with no problem in the past, most patients can continue taking penicillin without problems.
-if you have not had penicillin since this reaction to cephalexin, you should see a physician who could to test you to penicillin, ideally an allergist. ...Read more

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I'm allergic 2 penicillin/prescribed cephalexin 4 a cellulitis infection in my arm from a iv. How fast would a serious reaction occur if allergic?

I'm allergic 2 penicillin/prescribed cephalexin 4 a cellulitis infection in my arm from a iv. How fast would a serious reaction occur if allergic?

Minutes to hours: A small proportion of penicillin allergic patients can have an allergic reaction to cephalexin. Drug allergic reactions can occur in minutes to hours if already sensitized. It is possible to develop serious allergic reactions after several days of being on the medication and in some cases even shortly after stopping the med. Allergy testing is available for penicillin but not cephalexin. ...Read more

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I'm allergic to penicillin. Was prescribed cephalexin for folliculitis. Stop taking it 3 days ago. Now I have hives all over. Delayed reaction?

Possible: A small % of people who are allergic to penicillin may also react to cephalosporin such as cephalexin. However, if your reaction did not occur until about 10 days after you started to take the medication, this may well be a true allergic reaction specific to cephalexin. ...Read more

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I have a whitehead abcess beside a broken tooth. When I was a child I broke out from penicillin. And I don't know if I can take cephalexin. Can I?

I have a whitehead abcess beside a broken tooth. When I was a child I broke out from penicillin. And I don't know if I can take cephalexin. Can I?

Abscess/Cephalexin: This sounds like a dental abscess. Use warm compresses frequently to encourage it to drain. Allergy to Penicillin is often over diagnosed so at some point look into it further. Cephalexin is not considered a good alternative if you have a Penicillin allergy. A medication called Clindamycin would be a better choice. Be sure to see your dentist to manage your abscess and your broken tooth. ...Read more

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I am allergic to keflex & penicillin. Is neosporin still ok to use on my skin?

Neosporin: People have a tendency to assume that neosporin does not cause side effects because it is a widely available and frequently used nonprescription product. However, this is simply not the case. In fact, many healthcare providers now recommend that people avoid products with neomycin (including neosporin), as neomycin is more likely than most other antibiotics to cause allergic reactions. ...Read more

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Always fine w penicillin, but had extreme allergic reaction reaction to keflex! Does that mean I am now also allergic to penicillin for sure?

Always fine w penicillin, but had extreme allergic reaction reaction to keflex! Does that mean I am now also allergic to penicillin for sure?

Not necessarily: While penicillin and Cephalexin (keflex) share some features, allergy to one does not necessarily to one mean that you are allergic to the other. See a board-certified allergist/immunologist to sort things out. ...Read more

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Was recently dx'd with lupus & am allergic to Keflex. Heard that lupus patients tend to have strong reactions to penicillin, should I avoid penicilin?

Avoid penicillin: I am not aware of the connection between allergy to PCN and lupus, You need to avoid PCN if you are allergic to keflex. ...Read more

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I got allergy from penicillin 45 yrs ago when I was 8 yrs, since then I have not used it. Now due to UTI I am given keflex. Shd I take it. Advice plz?

I got allergy from penicillin 45 yrs ago when I was 8 yrs, since then I have not used it. Now due to UTI I am given keflex. Shd I take it. Advice plz?

Usually okay.: We were taught for years that there is about a 10% risk of being allergic to cephalosporins (like Keflex) in people who were allergic to drugs in the penicillin family. Later research has said that is a myth, and there is less than a 1% risk depending on the type of cephalosporin. See http://www. Ncbi. Nlm. Nih. Gov/pubmed/21742459. Talk to your doctor about your fears, though. ...Read more

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I took Keflex and had hives all over my body, was told not to use Penicillin or Sporin dugs. Hives again from Neosporin, Can I take the Shingles Shot?

I took Keflex and had hives all over my body, was told not to use Penicillin or Sporin dugs. Hives again from Neosporin, Can I take the Shingles Shot?

Shingles shot: Reaction to antibiotics should not affect you getting the shingles vaccine. They are unrelated. However yes you could be allergic to the shingles vaccine but there is no way to know until you get it. The good news it is only a one time shot so you won't need boosters. ...Read more

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I read that the flu shot is made from antibiotics. Safe for people allergic to keflex and penicillin?

I read that the flu shot is made from antibiotics. Safe for people allergic to keflex and penicillin?

No/ Yes: Influenza vaccines are made with dead viral antigens or inactivated live virus. They are not made with antibiotics and can be given to anyone who is allergic to antibiotics. ...Read more

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Is erythromycin ointment safe for someone who is allergic to keflex/penicillin? Also, if using for eye infection/stye, do I apply it inside my eye?

Is erythromycin ointment safe for someone who is allergic to keflex/penicillin? Also, if using for eye infection/stye, do I apply it inside my eye?

Yes and probably: Erythromycin is a macrolide antibiotic. It is not related to the penecillins nor cephalosporins to which you had allergies. There should be no cross reactivity. The standard treatment for stye is heat and compression (squeezing) then surgical incision and drainage if initial therapy is unsuccessful. If a patient has an eye infection with discharge, the antibiotic ointment goes inside the eyelid. ...Read more

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ER doctor prescribed me Keflex for possible mastitis and UTI knowing I'm allergic to penicillin. I am on day 3 and have an itchy rash on arms and legs?

ER doctor prescribed me Keflex for possible mastitis and UTI knowing I'm allergic to penicillin. I am on day 3 and have an itchy rash on arms and legs?

Possibly allergic: Cephalexin (Keflex) and related antibiotics (the cephalosporin group) are chemically similar to penicillinl. Although penicillin allergic persons usually can take them without problem, occasional cross reactions occur -- i.e. you may be allergic to the cephalexin. Check with the doctor who prescribed it. ...Read more

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Is it possible for you to mix penicillin 500 mg with keflex 500 mgvk 500 mg with acetaminophen?

Is it possible for you to mix penicillin 500 mg with keflex 500 mgvk 500 mg with acetaminophen?

Possible.: Pcn and Keflex cover just about the same organisms. Can take them together but may not need them both. There is no significant interaction between the drugs or with acetaminophen. ...Read more

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Can cefalexin cause any heart problems as a side effect, I'm allergic to penicillin is this safe for me to take, taking for chest infection 1g a day?

Can cefalexin cause any heart problems as a side effect, I'm allergic to penicillin is this safe for me to take, taking for chest infection 1g a day?

Penicillin allergy: Cephalexin can cause any type of drug allergy symptoms like anaphylaxis, angioedema, steven johnson syndrome, bone marrow suppression, hepatitis but heart problems do not seem to be listed as an side effect. About 90% of patient with reported penicillin allergy during childhood can tolerate penicillin. If there is a true penicillin allergy, there is a 2% risk of having Cephalexin allergy. ...Read more

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My doc gave me keflex to take prior to an upcoming procedure but im alergic to penecilian (sp). Should I be concerned about a possible reaction?

My doc gave me keflex to take prior to an upcoming procedure but im alergic to penecilian (sp). Should I be concerned about a possible reaction?

Maybe: Reportedly about 10% of penicillin-allergic patients will also be allergic to Keflex or other cephalosporins. If you develop a rash or difficulty breathing on penicillin, you should probably ask your doc for an alternative antibiotic. ...Read more

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If allergic to penicillan can I take keflex for a tooth abscess?

If allergic to penicillan can I take keflex for a tooth abscess?

Keflex: Keflex is a cephalosporin antibiotic and is not normally prescribed for dental infections. Since an antibiotic will not resolve your dental issues, your best bet is to see a local dentist and have the tooth evaluated. ...Read more

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If you are allergic to peniclin, could you also be allergic to cephalexin. Reason being I took it last night and when I woke up my lip was swollowing?

If you are allergic to peniclin, could you also be allergic to cephalexin. Reason being I took it last night and when I woke up my lip was swollowing?

Yes: There is a significant percentage of penicillin allergic patients who have a cross sensativity to cephalosporin antibiotics. In all likelihood you are allergic to Cephalexin as well as penicillin if you are experiencing swollen lips. Please contact your health care professional and you may need anti-histamine treatment. Stop the medication until prescriber is consulted. ...Read more

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22 weeks pregnant and on cefalexin 1mg 3times a day for last 5 days for upper uti infection. Allergies to penicillin and septrin. Symptoms worsening.

22 weeks pregnant and on cefalexin 1mg 3times a day for last 5 days for upper uti infection. Allergies to penicillin and septrin. Symptoms worsening.

? resistance: It is possible that you have a bacteria which is resistance to the cefalexin. Since you are pregnant and you have "upper tract" infection, it could become a significant problem. See your doctor soon. The urine can be tested to see to which antibiotics the bacteria is sensitive. ...Read more

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Does penicillan or keflex cure stds?

Does penicillan or keflex cure stds?

Killing bacteria: Both these drugs act by damaging the bacterial cell wall during cell replication. They cure std's by killing the infecting bacteria if they are susceptible to the drugs. ...Read more

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I've had chronic fatigue for 2 mths. I was told I had strep& given penicilon. A wk later I went back & was given keflex, taken all & still no change.

I've had chronic fatigue for 2 mths. I was told I had strep& given penicilon. A wk later I went back & was given keflex, taken all & still no change.

Cannot diagnose: Chronic ill-defined fatigue is one of the more frustrating things doctors see since it can be due to multiple factors and often to depression. Without being able to obtain a full history, physical exam and have labs available can only suggest you see a doctor who specializes in this area. In addition, answers on healthtap aren't intended for individual treatment, prescription or diagnosis. ...Read more

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Is there another drug combination for diverticulitis besides Flagel? I am also taking Bactrim due to allergies to Cipro, (ciprofloxacin) Keflex and Penecillin.

Is there another drug combination for diverticulitis besides Flagel? I am also taking Bactrim due to allergies to Cipro, (ciprofloxacin) Keflex and Penecillin.

Antibiotic allergies: You need the help of an ID doctor-since they are experts in antibiotics. First, I would want to 'define' ur allergies further-because sometimes a patient is labeled as 'allergic' & they aren't really allergic at all. That is really important. If ur truly allergic to penicillin, cephalosporins & cipro (ciprofloxacin) which is a fluoroquinolone, ur options are quite limited for oral therapy. Doxycycline might help. ...Read more

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Does Keflex cause yellow teeth? I've also been feeling very dizzy and have a sunburn rash. I do have an allergy to penicillan. Is this related?

Does Keflex cause yellow teeth? I've also been feeling very dizzy and have a sunburn rash. I do have an allergy to penicillan. Is this related?

Not common.: These are not typical side effects of Keflex Other antibiotics are more likely to do this. Are you taking any other meds or supplements? Certain foods and liquids can also cause yellowing of the teeth. Ask your doc to be sure and to find out what else could be going on that might cause this. We don't know why you are taking Keflex in the first place either. Call your doc! ...Read more

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If I am allergic to penicillin, can I take tazocin?

Piperacillin/tazobac: This compound contains a penicillin derivative and if you have a documented allergy to penicillin you should never ever take this drug. ...Read more

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What happens if I'm allergic to penicillin can I take biaxin (clarithromycin)?

No worries: These medications are not related and should not be a concern for a reaction in someone who is allergic to penicillin. ...Read more

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Can you tell me what you suggest if I'm allergic to penicillin, can I take mdma?

Can you tell me what you suggest if I'm allergic to penicillin, can I take mdma?

You shouldn't: But it has nothing to do with penicillin allergy. The two drugs are totally unrelated, but mdma is a dangerous drug in kids, even more so in a 39 year old, who should of given up that kind of nonsense long ago. Many mdma pills are not pure, and may contain other related chemicals, some of which are even more dangerous than the ecstacy itself. Molly, a particular brand of mdma has caused deaths. ...Read more

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If I'm allergic to penicillin can I take ceftin (cefuroxime)?

If I'm allergic to penicillin can I take ceftin (cefuroxime)?

Probably: There's about a 15% chance that you'll be allergic to ceftin (cefuroxime). If your penicillin allergy was life-threatening, you shouldn't take the risk, but if you just developed a rash, it's fine to try the ceftin (cefuroxime). ...Read more