The Secret of Great Health Care
Penicillin – which was derived from fungus - was first discovered in 1928. It was not produced for use until the early 1940's. While it was the second major class of antibiotic available it was very important because it was able to combat many illness that were not previously treatable including: syphilis, pneumonia, staph infections and tuberculosis.
While the drug was initially hard to produce in large quantities, a technique was developed using a moldy cantaloupe that allowed scientists to be able to mass-produce the antibiotic by 1944.
Interestingly, resistance to penicillin was noticed only three years after is was introduced as a medicine to fight infection. Penicillin resistance is a major problem today.
Penicillin is made up of 4 generations. Each generation has a little bit different coverage. This chapter will look at the three most common penicillin antibiotics prescribed in the doctor’s office: Penicillin V Potassium, amoxicillin and amoxicillin-clavulanate.
Penicillin kills bacteria by attacking the bacteria's cell wall. Many bacteria are now resistant to penicillin. It has done this by producing an enzyme that prevents the antibiotic from breaking down the cell wall.
Consequently, some derivatives of penicillin have been developed that have another substance meant to combat this resistance. Amoxicillin-clavulanate is one example of this. Many of the intravenous forms of antibiotics have added an antibiotic that combats the problem of antibiotic resistance.
Penicillin treats a wide range of conditions. Penicillin V potassium has the most narrow spectrum of action, followed by amoxicillin and amoxicillin-clavulanate can cover the widest range of infections.
Table 3: Practical use of penicillin antibiotics
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Drug |
Common uses in the doctor’s office |
Notes |
|
Penicillin V Potassium |
Its main use in the doctor’s office is in the first line treatment of strep throat. |
Best taken one hour before or 2 hours after meals. Most common side effects are diarrhea, vomiting, nausea and rash. |
|
Amoxicillin |
Sinus infections, ear infection, bronchitis, strep throat and treats bacteria that causes stomach ulcers. |
Can be taken with or without food. Most common side effects are nausea, vomiting, rash and diarrhea. |
|
Amoxicillin-Clavulanate (Augmentin) |
Sinus infections, pneumonia, ear infections, other respiratory infections and skin infections. |
Should be taken with food, as it is more likely to cause stomach upset. |
Penicillin is the most likely antibiotic to cause a severe allergic reaction, but the reaction is not as common as generally believed. Many people who report an allergy to penicillin are not actually allergic - either because the allergy went away or lessened over time. It is estimated that 10% of the population is allergic to penicillin.
The most common side effects include:
Less common side effects include:
Most side effects of penicillin are mild. Immediate medical attention must be obtained if there is any swelling of the throat, breathing difficulty or wheezing.
Allergy, while not a side effect, is common with penicillin. When the allergy is hives, decreased blood pressure, or difficulty breathing due to swelling in the mouth and throat than the allergy is considered severe and any antibiotic that is close to penicillin should not be given.
Many of those allergic to penicillin are also allergic to cephalosporins (see next chapter), but some evidence suggests that there is no or little cross reactivity to later generation cephalosporins.
Those who have a mild allergic reaction, such as a rash, may be tried on other antibiotics in a similar class (Cephalosporins) and watched closely. If there is a serious allergic reaction to penicillin – such as difficulty breathing or hives – then the use of cephalosporins is not recommended.
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Life saving key point |
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If you are allergic to penicillin, you may also be allergic to another class of medications known as cephalosporins. |
The main first generation penicillin is Penicillin V Potassium. While it can treat a wide range of infections (see table 3), it is the drug of choice in strep throat. The oral suspension of this drug has a bitter taste and therefore amoxicillin suspension is often substituted in children for strep throat.
The main second generation penicillin in oral form is dicloxacillin. This drug is not commonly used in medicine today except it is used to treat skin infections.
The third-generation penicillin group is the most popular generation used in the doctor’s office. The two major oral antibiotics here are amoxicillin and amoxicillin-clavulanate (Augmentin).
Amoxicillin is used as a first-line treatment for sinus infections, ear infections, strep throat (especially in children because the suspension tastes much better than penicillin). Amoxicillin adds some gram-negative coverage to the good gram-positive coverage of the first and second-generation penicillin group (see table 4).
Amoxicillin-clavulanate (Augmentin) is commonly used in the treatment of many respiratory infections. It is associated with similar side effects, but the side effects are more prevalent. Side effects are mainly gastrointestinal. Common side effects include: diarrhea and upset stomach. This drug should be taken with food to lessen the risk of side effects.
Amoxicillin-clavulanate is often used as a second-line drug for those with many of the same illnesses that amoxicillin covers. This means that if amoxicillin does not work than on a return visit to the doctor, he/she may place you on amoxicillin-clavulanate. It is not recommended as a first-line agent because it has a broader range of coverage and has more side effects.
Amoxicillin treats many of the same infections just as effectively. Therefore, why use a more powerful antibiotic. Overuse of powerful antibiotics have the potential to lead to resistance of those antibiotics.
The main difference between amoxicillin and amoxicillin-clavulanate is obviously the clavulanate. What is the clavulanate? It is a medication called a beta-lactamase inhibitor and it prevents some bacteria from destroying the penicillin. It will often treat an infection that is resistant to amoxicillin.
Common uses of amoxicillin-clavulanate (Augmentin) include:
Fourth generation penicillins treat more severe infections but are only available in the intravenous form. They are associated with more side effects including bleeding disorders and electrolyte imbalances.
Table 4: Gram-positive and Gram-negative
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Gram-positive and gram-negative are terms that health care providers use to classify bacteria into two large groups. When the health care personal stains the bacteria, they can differentiate between two types of bacteria based on the physical and chemical properties of their cell wall. It is helpful to make this differential as gram-positive organisms and gram-negative organisms respond to different antibiotics. There are currently much more definitive ways to determine the exact bacteria that is causing the infection, but they do not provide results as quickly as the gram stain. It takes minutes to tell if the bacterium is gram-positive or gram-negative. It can take days for a culture to determine the exact bacterial cause of the infection. It therefore has good use in serious infection. It helps the doctor determine which antibiotic is likely going to have some effectiveness over the bacteria, while the doctor waits for the return of the more definitive culture. |
