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Generic Name: Cephalexin
Brand Name(s): Keflex
Information updated: April 1, 2000
Overview
Keflex belongs to a class of potent antibiotics called cephalosporins. It is one of the first of these to become available generically and is now often prescribed as cephalexin.
This drug works against a wide variety of germs, including those that cause infections of the skin, lungs, throat, prostate, urinary tract, bones, and ears.
Cephalosporins are broad spectrum medicines that were originally discovered in one of the world's most unlikely locations.
A fungus found close to a sewer outlet along the coast of Sardinia turned out to cure a number of nasty infections. From this chance observation many extraordinary antibiotics have been developed.
Side Effects and Interactions
Side effects from cephalosporin-type antibiotics are generally mild. Nevertheless, cephalexin can cause a range of digestive tract disorders.
Indigestion, stomach pain, nausea, vomiting and diarrhea have been reported. If diarrhea becomes severe contact your physician, as it may be a warning of drug-induced colitis.
Other infrequent reactions to be aware of include rash, itching, vaginitis, headache, confusion, joint pain, fatigue and dizziness.
Cephalexin may affect laboratory test results. Liver enzymes may become elevated and false-positive results may show up during certain diabetes tests. Make sure that the laboratory personnel are aware you are taking cephalexin if you have blood drawn.
And remember to report any symptoms or suspected side effects of cephalexin to your physician promptly.
Special Precautions
If you are allergic to penicillin-type antibiotics, alert your physician immediately. Some people who are sensitive to penicillin may also react to cephalexin.
Symptoms such as breathing difficulty, wheezing, sneezing, hives, itching, and skin rash require immediate emergency treatment.
Life-threatening anaphylactic shock may produce an inability to breathe and cardiovascular collapse and can occur within minutes of exposure.
People with kidney problems should receive cephalexin only under careful medical supervision as the dosage will most likely have to be modified to prevent toxicity.
Taking the Medicine
Although this antibiotic is absorbed more efficiently when it is taken on an empty stomach, the pills can be swallowed with food, especially if they upset your stomach.
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Joe Graedon is a pharmacologist. Teresa Graedon holds a doctorate in medical anthropology and is a nutrition expert. Their syndicated radio show can be heard on public radio.
© 2000
Reader Comments
The first time I took Cephalexin because I had an ingrown toenail. I also developed a rash on my penis. I did not relate the two together. But I just got another ingrown toenail and my rash is back. I cannot discribe how furious I am. This rash lasts 4 weeks and is excruciating. What can I do?!!
Posted by: R N S | September 3, 2007 8:09 AM
I also got a rash on my penis after using cephalexin. It lasted 4 weeks and was unbearable! Its healing and scar tissue has resulted in premature ejactulation due to hyper sensitivity and has ruined my sex life! Gee thanks a lot Doc! Anything I can do to fix this?
Posted by: RNS | January 22, 2008 4:32 PM
I am female and taking this drug to treat strep throat and a bacterial eye infection, and it is helping my throat and eyes to feel much better.
Posted by: B.L. | February 1, 2008 9:26 PM
I have taken Cephalexin (dosage of 500mg) for my bronchitis -- I'm allergic to certain chemicals, and I take every precaution to avoid them, yet sometimes they sneak up on me when I least expect it -- like a freshly opened and inflated air mattress for example. Make sure you air out one of those things for at least a day or two before your guests sleep on it if they have any kind of chemical sensitivities. But I digress.
I don't recall any side effects so I guess I'm lucky in that regard. However, it did 'seem' that with this last attack in October ('07), the meds just didn't work as quickly as I "thought" they should.
My main concern is that the anti-bi's purchased from XYZ pharmacy may not have the same potency as MNO pharmacy. Or that the potency may be reduced altogether no matter where you purchase.
I know the Graedons have spoken out about this, but is the "establishment" listening ? ? ?
Re the 'rash', would Calendula gel help??? Touch base with your doc, but it wouldn't hurt to ask, right?? You should be able to find it at your local health food / organic / natural products store.
Posted by: MG | February 3, 2008 11:05 PM
To the two people who had penis rashes. I am not a doctor, nor do I attempt to play one on the interweb, but I'd suspect that you both may have herpes & had a breakout due to the stress/toxic overload your system was under while on this med.
Look up Herx reaction or just...
http://en.wikipedia.org/wiki/Herxheimer_reaction
Posted by: JG | March 4, 2008 9:38 PM
My penis is red and swollen ... have finished the the course of ceph ... dont think i will do this drug again ........ just when I got my wife motivated for sex!
Jeez louise
Posted by: Rm | July 6, 2008 7:58 PM