Antibiotics and side effects

Basic structure of all quinolone drugs

Some BIO230 students might think that I am a bit alarmist with my dire warnings of the coming catastrophe of untreatable infectious, which is an almost certain outcome due to the use and overuse of antibiotics. From the New York Times comes an indication that these medicines bring additional problems. A recent publication in the Journal of the American Medical Association has found that a very popular class of antibiotics, the fluoroquinolones, appear to be associated with a large number of very serious side effects. In 2011 alone, over 2000 lawsuits were filed in this country by patients who had side effects after taking one of these drugs.

The fluoroquinolones are a class of synthetic antimicrobials, first characterized in the 1960’s during an organic synthesis reaction to produce chloroquin. One of the best known fluoroquinolones is ciprofloxacin which is the treatment of choice for anthrax infection,  and so was seen widespread in the media during the anthrax terror event of 2001. Synthetic antimicrobials, in contrast to natural antimicrobials, are completely produced in the organic chemistry laboratory and do not begin their “life” as the byproduct of microbial metabolism. Several members of this family do have a significantly higher risk associated with them in causing patient colonization with MRSA isolates or Clostridium difficile, in comparison with other antibiotic treatment regimens. As such, the risks of developing nosocomial infections or promoting the development of antibiotic resistance in other microorganisms has been well appreciated for the fluoroquinolones. Their main utility however continues to be due to the fact that they are broad spectrum antibiotics, and can be used when the etiologic agent of disease has not been determined.

A pharmacologist friend of mine once remarked that “Every drug we use has two effects: the one we know about, and the one we don’t know about.” The utility of an antibiotic stems from its ability to stop the growth or kill a microorganism colonizing the human body, and the principle of selective toxicity means that the design of antibiotics should maximize their effects on microorganisms, while minimizing their effects on human tissues. Unfortunately, no completely selectively toxic antibiotic exists, and consequently unforeseen and unfortunate side effects can frequently occur. The New York Times article tells the story of Lloyd Balch, who took Levaquin for a mild case of pneumonia:

In addition to being unable to walk uphill, climb stairs or see clearly, his symptoms included dry eyes, mouth and skin; ringing in his ears; delayed urination; uncontrollable shaking; burning pain in his eyes and feet; occasional tingling in his hands and feet; heart palpitations; and muscle spasms in his back and around his eyes.

Several months after taking only a second pill, the conditions persisted. As might be apparent from his case study above, symptoms can strike any organ in the body. One reason that these types of side effects are poorly documented is because the medical community lacks significant long term studies on the safety and side effects of popular antibiotics, likely because many of these drugs are typically prescribed for only a short period of time to treat a certain medical condition. Best practices in any case recommend that this class of antibiotics should not be generally prescribed for patients most likely at risk for an adverse reaction (under 18 years old or over 60; pregnant or nursing women), or for patients who have demonstrated an adverse reaction to another antibiotic. In any case, it is essential for consumers to take the initiative and ask their health care worker to clarify what the drug is being taken for, how long it should be taken, what types of side effects have been reported before, and when those side effects typically manifest themselves.

BONUS: As before, commenting below will result in changing an existing quiz grade to a “5”, and furthermore will allow you to participate in my other class bonus opportunity. Comment below by 1) listing ANY antibiotic, 2) list the type of infection it is used to treat, and 3) listing ONE side effect. Please give a link to where you find it. Offer is open until Friday, September 21st.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on September 11, 2012, in Bonus!, Danger danger danger!. Bookmark the permalink. 21 Comments.

  1. I am fully on board with the over use of antibiotics. I am a nurse on a skilled unit on a retirement facility and thus I am constantly dispensing antibiotics to treat UTIs. The thing that amazes me and proves exactly what Dr. Singleton is saying about building resistance is many of my residents are treated with either IM or even IV antibiotics due to the fact at this point that is all that will treat their, what one would consider, a simple UTI. I have a friend who was a nurse in another state and it was their policy to only treat UTIs if the resident displayed at least 2-3 of the 5 predesignated symptoms to help cut back on the over use of antibiotics. This in the long run actually reduced the number of UTIs seen in the facility. The big draw back however to the wait and see approach in the elderly is that they can develop septicemia very quickly. So the antibiotic I chose to share is Ceftriaxone or as I call it at work Rocephin. I dispense it mainly to my residents to treat UTIs. The warning and precautions area also states that bacterial resistance may develop over time. This drug is also extremely hard on the liver.


    And this all brings me to my final point I am now getting lab results for my residents with UTIs that they are getting strains that are resistant to all antibiotics, which at that point we have no choice but to wait and see what happens.

    • Cephatriaxone is from the cephalosporin class of β-lactam antibiotics, and consequently affects the strength of the peptidoglycan layer in the prokaryotic cell wall. The Wikipedia entry for Cephatriaxone appears to indicate that the antibiotic would be prescribed for Chlamydia infections, which confused me as that organism does not have any peptidoglycan in its cell wall. A more careful reading of the entry indicates that another drug (azithromycin) is given in combination with cephatriaxone for gonorrheal infections, as patients are typically also infected with Chlamydia at the same time.

  2. I do also agree with the fact that we are over dispensing antibiotics, and this article just supports why perfectly. Although I do not ingest antibiotics often, I am still guilty of using them! I have had several sever ear infections, and so that is why I am choosing to talk about the Sulfonamide Antibiotics , a synthetic form of Penicillin. This is a common antibiotic used to treat cases of ear infections. Side effects include mild naseau, vomiting, diarrhea, and rashes. Fortunately I never experienced any of these side effects.
    I got this information from!

    • Sulfonamides are actually very different from penicillins, and members of the sulfonamide class of drugs were among the very first antimicrobial compounds that were available to treat disease, the “sulfa” drugs. They actually work by blocking the ability of a cell to make DNA precursors, by acting as a mimic in folic acid biosynthesis. Unlike the penicillin derived drugs, the sulfonamides are very broad spectrum, affecting a number of Gram positive, Gram negative, and Gram variable bacteria, as well as some other non-prokaryotic pathogens.

  3. I feel that antibiotics are used way too much in the medical field for a “quick fix” at any sign of infection. I think that more preventive steps should be taken to avoid the need for antibiotics. I personally have experienced bad side effects from the use of an antibiotic called Amoxicillin. It can be used for infections caused by bacteria such as pneumonia and others listed by the website. It can have side effects, also listed by the website, such as upset stomach, diarrhea, vomiting and other, more severe side effects. In my case, I was taking Amoxicillin often for chronic sinus infections which, after long-term exposure, created a resistance/allergy to the drug that resulted in a severe skin rash. Working in the hospital setting, I have seen this occur often where patients have presented with the same infections over and over again and are given the same antibiotic each time that eventually has no affect. It’s a very interesting, yet unfortunate, issue arising in healthcare today that, as discussed in lecture, will become more prevalent in the future.

    • Amoxicillin is a member of the penicillin class of antibiotics. Individuals with an allergy to one member of the family may well have an allergy to other penicillin like antibiotics. Patients then are advised to completely avoid all similar antibiotics as a precautionary measure.

  4. Paromomycin is an antibiotic used to target intestines with a type of parasite infection. Although effective, the medicine can not be absorbed into the bloodstream, so it will not help outside the intestines.
    People with hepatic encephalopathy can also take paromomycin to aid the deteriorated liver in disposing of the excess ammonia in the intestines.
    For every medication, there are side effects to be considered. Here, vomiting, heartburn, diarrhea, and nausea are a few to be considered.

    This information was found on both of these sites:

    • According to Wikipedia, paromomycin affects the 16S ribosomal subunit of cells, and is a broad spectrum similar in action to neomycin. It has effects against E. coli and S. aureus, as well as against eukaryotic pathogens as Michele stated right above. From those two facts, you should surmise that paromomycin would potentially have very significant side effects if taken inappropriately!

  5. Christa Gurriera

    Trimethoprim-sulfamethoxazole is an antibiotic used to treat urinary tract infection and bronchitis. In addition, it is used to prevent PCP (a serious kind of pneumonia). This antibiotic gets rid of the bacteria that is causing the infection. This treatment is commonly used on patients who lack strong immune systems. Trimethoprim-sulfamethoxazole has a side effects just like any other antibiotics. Some of the more common side effects include appetite loss, mild diarrhea, nausea, and vomiting. There are also more serious side effects.

    This information can be found on:

    • Trimethoprim is one of the sulfanomide (“sulfa”) class of drugs, which act by inhibiting a metabolic pathway essential for nucleotide biosynthesis. As we will see in Chapter 10, many antibiotic compounds and be subtly altered, maintaining the efficacy and mode of action, while offering novel beneficial properties or perhaps an ability to counteract antimicrobial resistance.

  6. Clindamycin, belongs to a class of medications called lincomycin antibiotics; is used to treat certain types of bacterial infections. These infections include: infection of the lungs, skin, blood, female reproductive organs, and internal organs. Clindamycin slows or stops bacterial growth. Common side effects of this antibiotic include but are not limited to nausea, vomiting, and joint pain. More serious side effects occur.

    Information gathered from:

  7. Oxacillin belongs to the penicillin antibiotic group. It is used to treat different types of staphylococcal infections (staph). There are many side effects associated with oxacillin as there would be with any other drugs A major effect is that oxacillin makes birth control pills less effective and could result in pregnancy. Another side effect is that it may cause diarrhea.


    • Many antibiotics have the ability to cause diarrhea, and the reason is rather simple. Antibiotics given for a Staph infection for instance cannot discriminate in many cases between the bacteria causing the infection and the normal bacteria present in the digestive tract (the normal flora). When the normal flora get wiped out by the antibiotic, diarrhea is the result!

  8. There are a few different antibiotics that treat Urinary Tract Infections, however this segment will focus on Ciprofloxacin (Cipro). This antibiotic kills the bacteria that causes these infections and can be administered in either a pill or liquid form. However, as with every kind of medication, there can be some detrimental side effects. One of these could be experiencing pain after exercise, mainly in your appendages. Pain such as this should be discussed with your doctor immediately if it occurs.

  9. Gonorrhea is a bacteria contracted from sexual contact with an already infected victim. In order to properly kill this bacteria, the antibiotic Suprax can be taken. If taken properly, this antibiotic can cure the victim completely of Gonorrhea, however if it is not taken correctly they will obviously not be cured. Gonorrhea has become resistant of other drugs such as penicillin and the “sulfa” drugs. A harmful side effect of this antibiotic includes black or bloody stools as well as unusual bleeding or bruising and your doctor should be called immediately at the onset of these symptoms.


  10. Erica Stackhouse

    Recently, I have been prescribed a series of medications all to treat a bacterial infection. A recent medication that I have used is Cefdinir, a generic brand of the brand name Omnicef. This medication is commonly prescribed for a wide range of bacterial infections such as bronchitis or pneumonia. It also can be used to UTI and bladder infections. This medication is normally easy to take, and doesn’t produce many side effects. The most common side effect would be diarrhea and nausea, the same side effects as many other bacterial medications.


    • Cefdinir is in the cephalosporin class of antibiotics, which are similar in structure and function to the penicillins. The have a similar mode of action to those antibiotics as well.

  11. Gabrielle Petrancuri

    Levofloxacin is in the group of antibiotics known as fluoroquinolones. Levofloxacin is an antibiotic that is used to treat specfic infections such as pneumonia chronic bronchitis, urinary track infections, and skin infections. This antibiotic has multipe harmful side effects, the most prevelent being tendinitis in the shoulder, hand, ankle, etc.

    • The neat thing about many antibiotics is that we can “tweak” them in relatively minor ways, for example ciprofloxacin and levofloxacin are very similar chemically with identical modes of action, yet they may have different pharmacological behavior in the body.

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