- Do not share drinks, food, and utensils with others until the healthcare
provider determines that the patient is no longer infected by the microbial.
Sharing may enable the microbial to spread to other people. - Recognize the expected effects, side effects, and adverse reactions that
might occur as a result of taking the medication. Also provide the patient with
a telephone number to call if the patient has questions about these effects. - Wear a Med-alert bracelet if the patient has allergies to medication.
PENICILLIN
Penicillin (PCN) is derived from molds that you sometimes see on bread and
fruit. It was discovered in 1940 and remains the most effective—and least
toxic—antimicrobial drug. Penicillin weakens the cell wall of a bacteria result-
ing in the rupture and destruction of a cell, which is called lysis.
Penicillin is most active against gram-positive bacteria and some gram-
negative bacteria. However, it isn’t active against bacteria that contain enzymes
that destroy penicillin.
There are four types of penicillin:
1.Basic (natural)
2.Penicillinase-resistant (resistant to beta-lactamase inactivation)
3.Aminopenicillins (broad spectrum)
4.Extended-spectrumBesides route, dose, and time, drugs are also characterized by pregnancy cate-
gory,protein-binding, and half-life. Pregnancy category indicates if the drug has
been tested using pregnant women and how safe the drug might be if used during
pregnancy. Penicillin is categorized by its usefulness against bacterial enzymes
capable of destroying the drug. Four different classifications of antibiotics exist
that contain the beta-lactam ring and are more active against gram-negative cell
wall organisms and decrease its susceptibility to enzymes that inactivate the
antibiotic. Protein-binding is when a drug binds to plasma proteins. When a drug
is bound to a protein it is not available for therapeutic use. The percent of pro-
tein binding is the amount of drug that can’t be used until it is released when the
free drug or the amount not bound to protein is excreted from the body. Half-life
is the amount of time for half the drug to be eliminated from the body.
The category appears at the top of the table if the value of the category applies
to all the drugs in a table, otherwise the category appears beneath the name of
the drug in the table.
CHAPTER 13 Antimicrobials—Fighting Infection^209