12.5 Penicllins

To help with comparing the medications and to learn important considerations for each medication, refer to the: Chapter 12 Antimicrobials Medication Cards

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.

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

Administration: oral, IV, IM

• Oral: take with a full glass of water.  Do not take with acidic juices, tomato juice, cola, caffeine as these will inactivate the med. take of an empty stomach as food can decrease absorption.  If GI upset, take with food.

Pediatrics: Penicillin 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.

Pregnancy: Penicillin can be used during pregnancy and safe to use while breast feeding.

Pen has a high concentration of potassium. Caution with client is taking potassium supplements.

Monitoring:

• check for allergies to Pen or cephalosporins before first dose.
• prior to first dose, ensure that cultures are not required.
• if high doses, assess INR, platelet count and PT
• monitor for systemic effects such as temperature, WBCs, and cultures
• monitor for changes in stool due to risk of C. Diff
• narrow therapeutic range so ensure regular dosing.

Drug Interactions:

There is a cross-sensitivity for clients allergic to cephalosporins.  Clients on high doses of penicillin may experience significant coagulation abnormalities.^[2]

Other notable drug interactions with Pen include the use of diuretic therapy, NSAIDs, oral contraceptives

Drugs that can lead to a decrease effectiveness of Pen include tetracycline, parenteral aminoglycosides (e.g., neomycin).

In addition to general antimicrobial administration considerations, it is important to monitor clients who receive penicillin for signs of superinfections such as C-diff or yeast infections.   Be alert for a change in bowel movements such as diarrhea, bloody stools and abdominal pain.

Client Teaching

• 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 with citrus-based products, which can impede absorption.  Additionally, clients should be instructed to chew oral chewable tablets thoroughly before swallowing.
• 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.
• Do 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 (Unbound Medicine, n.d.).

Penicillin Medication Card

Now let’s take a closer look at the penicillin medication card (Velarde, 2018). 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. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.

References