3.5 Penicillin

Now that we have reviewed antimicrobial basics, administration considerations, and the nursing process regarding antimicrobials, we will take a closer look at specific antimicrobial classes. 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, indications (i.e., therapeutic effects), nursing considerations, common side effects/adverse effects, and health teaching for this class/subclass of medication.

Each section also includes a medication grid to assist students to learn key points about each medication. Basic information related to a common generic medication for each class is outlined, including administration considerations, therapeutic effects, and common side effects/adverse effects. Prototype/generic medications listed in the medication grid are also linked to a free resource from the United States National Library of Medicine called DailyMed. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication. To read more about specific medications, go to the home page of DailyMed and enter the drug name in the search bar.

Penicillin

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]

Mechanism of Action: Penicillins are bactericidal and kill bacteria by interfering with the synthesis of proteins needed in their cellular walls.^[2] When the bacterial cell wall is impaired, the cell is rapidly broken down and destroyed.

Indications: Penicillins are prescribed to treat a variety of infectious processes such as Streptococcal infections, Pneumococcal infections, and Staphylococcal infections. Penicillins may be administered orally, IV, or intramuscularly.

Nursing Considerations: Clients receiving penicillins are at risk for developing superinfections such as C-diff or yeast infections.  Probiotics may be encouraged to prevent these superinfections.

There is a cross-sensitivity for clients allergic to cephalosporins, meaning they may also have an allergic reaction to penicillin. Additionally, clients who are prescribed high doses of penicillin may experience significant coagulation abnormalities.^[3] Other notable drug interactions include the use of diuretic therapy with penicillin. Penicillin contains a significant amount of potassium, so clients receiving potassium-sparing diuretics or potassium 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.

Side Effects/Adverse Effects: Common side effects for penicillin include nausea, vomiting, gastrointestinal (GI) distress, and diarrhea. Other side effects may include the presence of a black hairy tongue.  Clients should be monitored for C-diff, candidiasis, and hyperkalemia. Other signs of hypersensitivity may include rash (maculopapular to exfoliative dermatitis), urticaria, laryngeal edema, and anaphylaxis. If an allergic reaction occurs, penicillin should be discontinued and appropriate therapy instituted. Serious anaphylactic reactions require emergency treatment with epinephrine and airway management support.

Health Teaching & Health Promotion: The client should notify the health care provider (HCP) if fever or diarrhea develops, especially if the stool contains blood, pus, or mucus. Advise the client not to treat diarrhea without advice from HCP. If GI upset occurs, the client may take the medication with meals but should avoid taking it with citrus products, which can impede absorption. Additionally, clients should be instructed to thoroughly chew chewable tablets before swallowing. The client should report a rash or any signs of superinfection such as vaginal itching or discharge (indicating a yeast infection) or loose or foul-smelling stool (indicating a possible C-diff infection).

Clients should be instructed to take medication as prescribed 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, a type of penicillin, and until their next menstrual period. Clients should notify their HCP if symptoms do not improve.^[4]

Now let’s take a closer look at the penicillin medication grid in Table 3.5.^[5]

Table 3.5 Penicillin Medication Grid^[6]