Now that we have reviewed antimicrobial basics, common bacterial infections and the nursing process when administering antimicrobials, and general administration considerations, we will take a closer look at specific antimicrobial classes and administration considerations, therapeutic effects, adverse effects, and specific teaching needed for each class of antimicrobials. Each of the following sections of this chapter is based on a class or subclass of anti-infective medications.  Each section discusses the mechanism of action, specific administration considerations, and common client teaching for this class/subclass of medication.  Each section is then followed by a medication table with a common generic medication and its specific administration considerations, therapeutic effects, and side effects/adverse effects for this medication.

Penicillins

Penicillin was the first antibiotic discovered and its detection came as a bit of an accident. In 1928, Alexander Fleming, a professor of bacteriology at St. Mary’s Hospital in London, discovered penicillin accidentally growing in a petri dish in his lab. The penicillin was the result of mold juice that had grown there inadvertently. Fleming noted that this “mold juice” inhibited the growth of Staphylococcus bacteria that was previously growing in the petri dish. Subsequently, the first antibiotic discovery was made.^[1]

Indications for  Use

Penicillins are prescribed to treat a variety of infectious processes such as Streptococcal infections, Pneumococcal infections, and Staphylococcal infections. They are considered broad-spectrum for gram-positive bacteria, but have little effectiveness for gram-negative bacteria. Penicillins may be administered orally, IV, or intramuscularly.

Mechanism of Action

Penicillins are bactericidal and kill bacteria by interfering with the synthesis of proteins needed in their cellular walls. When the bacterial cell wall is impaired, the cell is rapidly broken down and destroyed.

Nursing Considerations Across the Lifespan

Penicillins are considered safe for children, with dosages varying based on pediatric clients’ weight. No dosage adjustment is required for clients with hepatic or renal impairment. Penicillins can be used during pregnancy.

Specific Administration Considerations

In addition to general antimicrobial administration considerations, it is important to monitor clients who receive penicillins for signs of superinfections such as C-diff or yeast infections.  There is also a cross-sensitivity for clients allergic to cephalosporins.  It is important to remember that clients who are prescribed high doses of penicillin may experience significant coagulation abnormalities.^[2] Other notable drug interactions include the use of diuretic therapy with penicillin. Penicillin contains a significant amount of potassium. Clients receiving potassium-sparing diuretics or supplementation should be monitored for signs of hyperkalemia. Penicillin is best absorbed on an empty stomach; however, many clients may experience GI upset and subsequently take the medication with food.

Client Teaching & Education

The client should notify the health care provider (HCP) if fever or diarrhoea develops, especially if the stool contains blood, pus, or mucus.  Advise the client not to treat diarrhoea without advice from HCP. If GI upset occurs, the client may take the medication with meals but should avoid taking with citrus-based products, which can impede absorption.  Additionally, clients should be instructed to chew oral chewable tablets thoroughly before swallowing.  The client should report a rash or any signs of superinfection (black, furry overgrowth on tongue; vaginal itching or discharge; loose or foul-smelling stool).

Clients should be instructed to take medication around the clock and to finish the drug completely as directed.  Doses should be spaced evenly to achieve the desired therapeutic effect.  Additionally, clients should receive instruction to not share medication and that any sharing of medications may be dangerous.  Clients with a history of rheumatic heart disease or valve replacement should receive instruction regarding the importance of using antimicrobial prophylaxis before invasive medical or dental procedures. Female clients taking oral contraceptives should use an alternative form of contraception during therapy with amoxicillin and until their next period.  Clients should notify their HCP if symptoms do not improve.^[3]

Penecillin Medication Card

Now let’s take a closer look at the penicillin medication card.^[4]

Medication grids are intended to assist students to learn key points about each medication.  Basic information related to a common generic medication in this class is outlined, including administration considerations, therapeutic effects, and side effects/adverse effects. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication. Prototype/generic medications listed in the medication card are also hyperlinked directly to a free resource from the United States National Library of Medicine called Daily Med. Other resources you can access for free for evidence-based medication information include: OpenMD and Merck Manuals. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.

Note: All drug cards are available in the Medication Cards Chapter as editable and printable documents.

Attributions

• Penicillin’s “Mechanism of Action” was adapted from Principles of Pharmacology by Carl Rosow, David Standaert, and Gary Strichartz (republished by LibreTexts), which is licened under a CC BY-NC-SA 4.0 licence.