General Health Topic - Heart Attack Signs

Hello Everyone,

I know we are in the middle of a series on How Antibiotics Work but I read something online and I thought I needed to let you know.

The article, by the Centers for Disease Control and Prevention, stated that only 1 in 4 Americans know the warning signs of a HEART ATTACK and what to do first. I do not want my readers to be in the group that doesn't know about the warning signs of heart attack.

Here are the signs and symptoms and can include one or more of the following 6:

1. Chest pain (most common symptom)
2. Shortness of breath
3. Pain or discomfort in the chest
4. Discomfort in the arms or shoulder
5. A feeling of weakness or lightheadedness
6. Discomfort in the jaw, neck or back

According to the American Heart Association, women are more likely than men to experience shortness of breath and back or jaw pain.

If you, a family member or co-worker experience these symptoms...CALL 911.

Sometimes patients are rushed to the hospital for heart attack symptoms and it turns out to be something entirely different. Don't worry about that. Consider that the symptoms are heart attack symptoms until proven otherwise!!!!

For more information, check out the following links:

The CDC publication: http://www.cdc.gov/mmwr
The American Heart Association: http://www.americanheart.org

Hopefully, this information is helpful. Please pass it on to all your friends, family and co-workers.

Thanks,

Dr. Paul

How Do Drugs Work - Cephalosporins

Hello Everyone,

The last post covered the first group of antibiotics, the penicillins. This post will cover the cephalosporins.

The cephalosporins are similar to the penicillins in that both contain an chemical structure called a beta-lactam ring.

The cephalosporins are classified by generation (1st - 4th generation) based on the types of bacteria they are active against (their spectrum of activity).

Here is a list of the cephalosporins:

1st Generation
• Cefazolin (Ancef, Kefzol)
• Cephalexin (Keflex)

2nd Generation
• Cefuroxime (Ceftin, Zinacef)
• Cefotetan (Cefotan)

3rd Generation
• Cefpodoxime (Vantin)
• Cefotaxime (Claforan)
• Ceftazidime (Tazicef)
• Ceftriaxone (Rocephin)

4th Generation
• Cefepime (Maxipime)

Generally speaking, the 1st and 2nd generation cephalosporins are active against gram positive organisms while the 3rd and 4th generation have activity against both gram positive and gram negative organisms.

The cephalosporins work the same way the penicillins do; they inhibit the formation of the bacterial cell wall.

Since the cephalosporins are structurally related to the penicillins, if a patient has a true penicillin allergy, they may also be allergic to the cephalosporins. The actual rate of cross-sensitivity is not well defined. Therefore if a patient has a penicillin allergy (anaphylaxis, urticaria or angioedema) the cephalosporins should be avoided.

For more information on cephalosporins, please check out:

http://www.surgicalcriticalcare.net/Lectures/antibiotics.pdf

Please let me know if you have any questions or comments.

Stay Well,

Dr. Paul

How Do Drugs Work - Antibiotics - Penicillins

Hello Everyone,

Today we are going to discuss the Penicillins. There are several different types of penicillins, however, they have all the same basic mechanism of action (MOA).

Natural Penicillins
• Penicillin G
• Penicllin G procaine
• Penicillin G benzathine
• Penicillin VK

Penicillinase-resistant Penicillins
• Nafcillin
• Dicloxacillin

Aminopenicillins
• Amoxicillin
• Ampicillin

Carboxypenicillins
• Ticarcillin

Ureidopenicillins
• Piperacillin

Penicillin B-Lactamase inhibitors
• Amoxicillin-clavulanic acid
• Ampicillin-sulbactam
• Ticarcillin-clavulanic acid
• Piperacillin- tazobactam v

Mechanism Of Action (bactericidal/bacteriostatic) - Penicillins act by inhibiting bacterial cell wall synthesis. They inhibit enzymes that create a cross-linkage between the bacterial peptide chains and prevent the formation of the bacterial cell wall. These enzymes are the penicillin-binding proteins.

Spectrum (Gm+, Gm-, anaerobes) Gram +: streptococci, Enterococcus, but NOT
S. aureus. Gram - : only a few (E. coli, Proteus spp, a few others)…lots of resistance

No below-the-diaphragm anaerobic activity

I f you would like some more in-depth inormation on penicillins or antibiotics in general you can check out:

http://www.surgicalcriticalcare.net/Lectures/antibiotics.pdf
http://students.washington.edu/rhochi/antibiotics.pdf

Next post will cover the the cephalosporins.

Stay well.....

Dr. Paul

How Do Drugs Work - Classes of Antibiotics

Hello Everyone,

I was at a meeting all last week and I didn't have time to write. I am glad to be back.

On my last post I wrote about different types of bacteria, Gram Positive, Gram Negative and Anaerobes. Now I am going to start talking about the different types of antibiotics that are used to treat the different types of bacteria.

Now you might think that the antibiotics are used to treat different types of conditions like pneumonia or skin infections. However, the antibiotics are selected to work against the most common type of bacteria that cause those conditions (empiric therapy) or to treat the actual type of bacteria once it has been identified.

There are several different classes of antibiotics that are used to treat the different types of infections. The mechanism of action that these antibiotics use to halt the growth of bacteria (bacteriostatic) or to kill the bacteria (bacteriocidal) is different for the different types of antibiotics.

Some of the antibiotics are effective against Gram Positive organism, some are effective against Gram Negative organisms, some are effective against both types to some degree and others are effective against the anaerobes.We will discuss the different mechanisms of action for these antibiotics.

For now, I just want to introduce the different classes of antibiotics. Here they are in no particular order.

Penicillins
Cephalosporins
Tetracyclines
Aminoglycosides,
Flouroquinolones
Carbapenems
Macrolides
Sulfonamides
Glycyclines
Oxazolidinones
Monobactams
Other various agents that don't fit the above catagories.

Stay tuned for more information on the different classes of antibiotics.

Thanks,

Dr. Paul

How Do Drugs Work - Antibiotics - Part 1- Bacteria

Hello Everyone,

Before we talk about antibiotics, we need to know a little about the clinical bacteria that cause illness.

There are bacteria which normally occur on the outside of the body on our skin and in our nose and mouths. There are also bacteria that normally live inside our intestinal tract. Usually, those bacteria do not cause any problems for us. There are portions of the body that are sterile and do not contain any bacteria such as blood or spinal fluid.

So, a common organism that lives on the skin and is always present can cause significant problems if it gains entrance to an area that is usually sterile.

Knowing the type of bacteria that is causing an infection is usually one of the first things a physician needs to know. You are probably saying, "The last time I had an infection, the doctor prescribed an antibiotic right away. There in no way she could know what type of bacteria it was." True....kind of. There are many types of infection that are caused by the same types of bacteria. For example, pneumonia is usually caused by one of three types of bacteria. In addition, if the pneumonia was aquired out in the community or inside a healthcare facility will also give a clue as to the type of bacteria that cause the infection. Based on that knowledge, the physician can narrow the bacterial field and prescribe an antibiotic based on the suspected bacteria. Prescribing or administering an antibiotic based on common pathogens is called "EMPIRIC THERAPY".

However, knowing the type of bacteria is key. So, how are those bacteria classified?

Clinical bacteria are grouped into five categories based on gram stain appearance under the light microscope. Two groups have a general rounded shape (The COCCI) and stain either red or blue. Two groups have a general rod-like shape (The BACILLI) and stain either red or blue.

The organisms that stain blue or that can uptake the stain are called GRAM POSITIVE.

The organisms that stain red are called GRAM NEGATIVE.

There are some antibiotics that are affective against both Gram positive and Gram Negative organisms. Those are called BROAD SPECTRUM ANTIBIOTICS.

There are some that are effective against primarily Gram positive organisms as well as some that are effective against primarily gram negative bacteria.

Therefore, knowing if an organism is gram positive or gram negative is considered by many to be the single most important chacteristic of clinical bacteria.

Gram negative organisms have thinner cell walls and the cell wall composition is different from that of gram positive organisms. This difference also accounts for some general distinctions in susceptibility to antibiotic drugs.

In addition to the Gram Stain characteristic, knowing if the bacteria do or do not require oxygen to replicate is important. Some bacteria can grow only in the absence of oxygen and they are known as ANAEROBES. If they require oxygen, they are know as AEROBES. If the are flexible and grow in both conditions they are called FACULTATIVE ANAEROBES. Anaerobes account for 5 - 10% of all clinical infections. There are antibiotics that are effective against anaerobes.

Well, this is just a start and I will continue with my next post.

To be continued....

Dr. Paul