Cephalexin structure (racemic)
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Cefalexin (previously also British Approved Name Cephalexin) is a drug that is a member of the cephalosporin class of antibiotics. It is one of the most widely prescribed antibiotics. more...

Kainic acid


Cefalexin is used to treat urinary tract infections, respiratory tract infections (including sinusitis, otitis media, pharyngitis, tonsillitis and pneumonia), skin and soft tissue infections.

It is used in preference to one of the penicillin group when greater target site concentration is sought, bacterial have developed penicillin resistance, or for people allergic to a penicillin (there being only a 10% cross-over of allergy between the groups).


Cefalexin comes as capsules or tablets of 250 or 500mg, and liquids of 125 or 250mg per 5ml. It should be taken with a full glass of water.

It is marketed under a wide range of brand names (e.g. Biocef, Cefanox, Ceporex, Keflet, Keflex, Keforal, Keftab, Keftal, and Lopilexin)


Typical dosage is 250mg every 6 hours or 500mg every 8-12hours, and doubled in cases of severe infection. Smaller dosages are used for children based on weight or age.

Courses generally last for 7-10days, but just 3 days in the early treatment of uncomplicated urinary tract infection in women.


Cefalexin should not be taken by those known to be allergic to other members of the Cephalosporin group. Caution is required for those with known allergic to a member of the penicillin group as there is about a 10% cross-over rate between the groups.

Being a broad-spectrum antibiotic, its effect on gut flora may interfere with the effectiveness of the oral contraceptive pill.

Side Effects

Cefalexin is generally well tolerated with stomach or bowel upset the most likely side-effect. It may also cause fatigue or headaches.

Rarely allergic reactions, e.g. itching, swelling, dizziness or trouble breathing.

As per broad-spectrum penicillins, overgrowth with oral or vaginal yeast infections may occur.


  • FDA Drug Information PDF and Pharmacy Drug Information Insert.
  • British National Formulary '50' September 2005

Read more at Wikipedia.org

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Antibiotic-sensitive infections in CFS/Fibromyalgia
From Townsend Letter for Doctors and Patients, 5/1/05 by Jacob Teitelbaum

Many infections have been found in CFIDS. That people may have not just one, but several simultaneously, is significant. It suggests that although these infections may be a trigger, in most patients the immune system is suppressed, setting patients up for unusual infections that persist. These infections may then drag them down, further suppressing their immune system.


Fortunately, most people improve (and often get very healthy) by simply treating the sleep, hormonal, nutritional, and yeast problems. Once these areas are treated, their body can usually eliminate any persistent infections by itself. Some people, though, have infections that need treatment with antibiotics.

How can you tell if the patient needs antibiotics? First, I would try the other approaches discussed in earlier columns. I would consider long-term (6 week to 2 years) antibiotic treatments if the following symptoms persist: a fever over 98.6[degrees]F--even 99[degrees]F--and/or chronic lung congestion, sinusitis, skin pustules, or other evidence of chronic bacterial infections.

In my experience, people with these symptoms seem to be more likely to have bacterial, mycoplasmal, or chlamydial infections that respond to special antibiotics. This treatment is not to be undertaken routinely, however, as the long-term antibiotics can, of course, cause yeast overgrowth or antibiotic-resistant bacteria. Let's look at mycoplasma and chlamydia infections and how to approach them.

Mycoplasma and Chlamydia

Although other infections have also been found to be very important in CFIDS, mycoplasma and chlamydia are two types of microorganisms that can cause persistent infections and have similar characteristics. Dr. Garth Nicolson and his wife, Nancy L. Nicolson, who were both on-faculty in the Department of Microbiology and Immunology at Baylor University in Texas, have been the leading proponents of treatment of these infections. Dr. Nicolson was also an endowed chair and department chairman at the M.D. Anderson Cancer Center of the University of Texas in Houston, and a professor of Internal Medicine at the University of Texas Medical School, also in Houston. Nancy Nicolson had chronic fatigue syndrome years ago. They were surprised that her test turned out to be positive for the organism Mycoplasma incognitus (also known as Mycoplasma fermentans). This type of mycoplasma was found to be resistant to the penicillin- and cephalosporin-family antibiotics, such as Keflex, that most doctors use, but was sensitive to long courses of doxycycline and Cipro. After an extended course of doxycycline treatment, she was much better. The Nicolsons then went on to develop their own tests for mycoplasma using PCR testing.

Mycoplasma are a type of ancient bacteria that lack cell walls and are capable of invading a number of types of human cells. They can cause a wide variety of human diseases. These organisms can cause the types of symptoms seen in people with CFS/Fibromyalgia and, according to Dr. Nicolson, tend to be immune-suppressing. Unfortunately, they cannot be readily cultured on a culture dish like regular bacteria. In medicine, we have a bad habit of focusing on things that are easy to test for and making believe that things that are hard to test for do not exist. Because of this, bacterial infections such as pneumonia, bladder infections, and skin infections--in which one bacterium on a cell dish will rapidly turn into millions by the next day and be visible to the human eye--get all our attention. Unfortunately, mycoplasma and chlamydia, which cannot be easily cultured, tend to be ignored.

Although mycoplasma and chlamydia are common in the environment, they usually are fairly noninvasive. It may simply be that once the patient's immune system is weakened, these infections can get into cells where they don't belong. When that happens, even some of the common ones that are normally considered noninfectious can wreak havoc. When these infections reproduce slowly, they tend to be low-grade and chronic, as opposed to the acute and more prominent symptoms seen with bacterial and viral infections that multiply and divide rapidly.

Interestingly, the Nicolsons found that in patients with chronic fatigue syndrome or fibromyalgia, approximately 70% (144 out of 203 patients) had a positive PCR test for at least one--usually several--species of mycoplasma or chlamydia. When the Nicolsons tested 70 healthy patients, only 6 (less than 9%) were positive for any of the mycoplasma species. This is a highly significant difference. Only 2 of these 70 healthy people were positive for Mycoplasma fermentans. Similar results have been published by other doctors.

It is likely that there is a group of underlying problems and not a single one that triggers CFS/FMS. This applies to infections as well. For mycoplasma alone, when the Nicolsons checked for four different types of mycoplasma, over half of the 93 CFIDS patients that were positive had more than one type of infection. Over 20% of them had three out of the four mycoplasma infections test positive. The more infections they tested positive for, the worse their symptoms were and the longer they had had CFIDS/FMS.

The data suggest that many infections may trigger CFIDS/FMS or that CFIDS and FMS may cause immune suppression--which then sets you up to catch a whole bunch of different infections which the body has trouble clearing. This is why it is important to treat all of the underlying processes simultaneously.

Testing for These Infections

Do not even bother checking IgG or IgM testing for these. PCR testing can be helpful, but be aware that even with the best laboratories, it is not uncommon to have a false-negative report--where you have the infection but it does not show up on the test. There are good arguments for not doing the tests and simply going ahead and treating the patients empirically if they have fevers, lung congestion or pustular scalp lesions. If they feel better after 2-4 months on the treatment, then you know you are hitting an infection and you can always intermittently stop the treatment to see how long they will need it. Also, there are many infections that are not tested for with these tests that would be effectively treated with the regimens that we are discussing. Many of these are likely to be infections that we don't even know exist. Because of this, if resources are limited, I often simply treat the patient, based on clinical suspicion, without doing the tests.

Treating Mycoplasma and Chlamydia

Fortunately, both mycoplasma and chlamydia infections are usually sensitive to the right antibiotics. The antibiotics most likely to affect these organisms are the following:

* Doxycycline or minocycline, usually at dosages of 100 milligrams 2 times a day. These two antibiotics are in the tetracycline family. They are very effective against a number of unusual organisms (including, at times, Lyme disease). They should not be given to children under eight years old because they can cause permanent staining of the teeth.

* Ciprofloxacin (Cipro), usually 500 milligrams twice a day has a very wide range of effectiveness against a large number of organisms. When treating males, Cipro has the additional benefit of treating any hidden prostate infections, as does doxycycline. Do not give oral magnesium or any supplement containing magnesium within six hours of the Cipro or it can decrease absorption of the Cipro. I think that in time we will realize that Cipro can be fairly toxic in a subset of patients, actually causing fibromyalgia, tendonitis, and other musculoskeletal problems.

* Azithromycin (Zithromax), 250 milligrams a day or clarithromycin (Biaxin), 500 milligrams twice a day, taken on an empty stomach. These antibiotics are in the erythromycin family. Zithromax tends to be fairly well tolerated. Biaxin is more likely to cause a bit of nausea in some patients, but it is usually well tolerated. Both are quite expensive. They may work against infections missed by doxycycline and Cipro.

Although all of these antibiotics can be effective, it is not uncommon for infections that are sensitive to the erythromycin antibiotics (Zithromax or Biaxin) to be resistant to tetracycline antibiotics (doxycycline, minocycline) and Cipro, and vice-versa. Therefore, it is best to try either doxycycline or Cipro first. If they are not effective, then try the Zithromax or Biaxin. The antibiotic should be taken for at least six months. If there is no improvement in ~2-4 months, switch to or add the other antibiotic or simply stop the treatment. It is helpful to check for low-grade fevers. As mentioned earlier, I am more likely to use antibiotics for CFIDS patients who have temperatures over 98.6[degrees]F, even if it is only 98.8[degrees]F (I consider 98.8[degrees]F a fever because CFIDS/FMS patients usually have low body temperatures). If the fever decreases with the antibiotic, it suggests that the patient does have one of these nonviral infections and that the antibiotic is helping. This would encourage me to continue the antibiotic trial--even if it takes up to 18 months to see an improvement in their symptoms.

If the patient is clearly better, I would probably give the antibiotic for at least six to twelve months. It can then be stopped. If symptoms recur, keep repeating six- to eight-week cycles until the symptoms stay gone. It may take several years of treatment for the infection to be totally eradicated. To put this in perspective, this is how long children often take antibiotics for acne--which unfortunately, if not taken with antifungals, can lead to yeast overgrowth and possibly trigger CFIDS. You should therefore have the patient avoid sweets and give two tablets each of the Probiotic Pearls and the natural antifungal Phytostan (both from Integrative Therapeutics/ITI 800-931-1709) twice a day, while on the antibiotics. In addition, adding immune support can be very helpful. I highly recommend a natural thymic hormone mimic called ProBoost (from Klabin Marketing 800-933-9440). In my experience, this is a very effective immune stimulant. Dissolve the contents of one packet under the tongue three times a day for 6-12 weeks (then once a day as it costs ~$1.85/dose retail-but is well worth it) and let it absorb there (any that is swallowed is destroyed).

It is very common to get what is called a Herxheimer (die-off) reaction that includes chills, fever, night sweats, and general worsening of CFS/FMS symptoms when the antibiotic first kills off the infection. These symptoms can be severe and last for weeks. If this occurs, lower the antibiotic dose to the level tolerated (e.g.-doxycycline 25 mg every other day) and increase as able. Dr. Nicolson encourages patients not to abandon therapy prematurely. He notes that if they have been sick for years, it is unlikely they will recover in less than one year of treatment, so they should not be alarmed by symptoms that return or worsen temporarily.

by Jacob Teitelbaum, MD

Jacob Teitelbaum, MD is director of the Annapolis Research Center for Effective CFS/Fibromyalgia Therapies, which sees patients with CFS/FMS from all over the world (410-573-5389; www.EndFatigue.com) and author of the best selling book" From Fatigued to Fantastic!" and "Three Steps To Happiness! Healing Through Joy" His newest book "Pain Free 1-2-3!" has just been released. He gives workshops on effective CFS/Fibromyalgia therapies and pain management for both prescribing and non-prescribing practitioners (see www.EndFatigue.com). He accepts no money from any company whose products he recommends and 100% of his royalty for products he makes is donated to charity.

COPYRIGHT 2005 The Townsend Letter Group
COPYRIGHT 2005 Gale Group

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