The Importance of Penicillin

• It is important to understand the actions of penicillin and its effectiveness.  
• There are various drug interactions that can occur with penicillins and these must be recognized and fully understood.   
• The nurse has an important role in the administration and education of penicillin. 
  

Penicillin remains an essential agent in the treatment of various bacterial diseases despite the presence of other antibacterial drugs.  

This drug can be classified into different types and some are given orally while others are given parenterally.  The types are distributed widely to most areas in the body including the lungs, liver, kidneys, muscle, bone, and placenta.  High concentrations of penicillin also appear in urine which makes them useful in treating urinary tract infections.  

Actions

Penicillin has bactericidal actions and they bind reversibly to several enzymes outside the bacterial cytoplasmic membrane, such as penicillin-binding proteins (PBPs).  They are involved in cell division which interferes with the processes that inhibit cell-wall synthesis, causing rapid destruction of the bacterial cell.  

This drug class serves as an effective agent against a wide range of bacteria such as active gram-positive, gram-negative, and anaerobic organisms.  However, there are certain types of penicillin that are more effective against a particular organism.

Penicillin Drug Interactions

The drug interactions that can occur with penicillin include the following: 

• Probenecid increases the plasma concentration of penicillin; therefore if both are administered together, the doses need to be adjusted.  
• Penicillin can reduce the tubular secretion of methotrexate leading to toxicity because of a slowed excretion rate from the kidneys.  
• With the concomitant use of tetracycline and chloramphenicol, the antibacterial activity of this drug is reduced. 
• Neomycin decreases the absorption of penicillin V.  
• With ampicillin and penicillin V, the effectiveness of hormonal contraceptives is decreased which can lead to an unplanned pregnancy.  It is important to ask the patient to use another contraceptive method until penicillin therapy is complete since hormonal contraceptives may be affected. 
• Large doses of IV penicillin can increase the bleeding time by decreasing vitamin K  which can also increase the bleeding risk of anticoagulants.  Nafcillin and dicloxacillin can possibly lead to warfarin resistance. 
• It can worsen or precipitate hyperkalemia and hypernatremia 
• Aminoglycosides and clavulanic acid increase the antibacterial effects of penicillin and are used in combination therapy to treat severe infections.
  

Penicillin and Nursing Implementation

With this type of drug therapy, the follow nursing implementations are important to consider: 

• When giving other bacteriostatic drugs such as tetracycline, erythromycin, and chloramphenicol with penicillin, give a one-hour break.  Give penicillin at least one hour before the administration of these drugs because they can inhibit bacterial cell growth and decrease the rate of penicillin uptake by bacterial cell walls. 
• For reconstitution and dilution, follow the manufacturer’s guidelines and check the expiration date before administering the drug.  
• To enhance gastrointestinal absorption, administer oral penicillin one to two hours before meals. 
• After reconstitution of an oral suspension, place in the refrigerator where it can be kept for 14 days.  To ensure the correct dosage, shake the suspension well before use.   
• For intramuscular administration, use a large muscle such as a gluteal or mid-lateral thigh.  To minimize tissue injury, rotate injection sites and apply an ice pack over the area to relieve pain.  Never inject more than 2g of drug per injection site.  
• Never mix other drugs in the penicillin infusion bag, especially aminoglycosides that can lead to drug inactivation.  To administer other drugs intravenously, temporarily stop the primary drug infusion.  
• For intravenous administration, administer over 30 minutes either continuously or intermittently.  Rotate the infusion site every 48 hours.  
• Check the patient for a penicillin allergy test.  A patient who does not have a history of penicillin hypersensitivity may have future allergic reactions; therefore, one needs to be cautious with each administration.  
• Monitor the patient who receives long-term drug therapy for superinfections, especially the elderly, debilitated, and those receiving immunosuppressant or radiation therapy.   
• If an adverse gastrointestinal reaction occurs, check the patient’s hydration status.  
• Ask the patient to take the drug as the healthcare provider has prescribed and to not stop the therapy even if the symptoms subside.  Do not stop the drug abruptly as it can lead to antibiotic resistance, making the infection difficult to treat.  

The Bottom Line on Penicillin

Penicillin is an essential agent used in the treatment of bacterial infections but can have varying adverse reactions that need to be reported.  Inform the patient to report if they have any fever, chills, or rash with as it can occur due to a hypersensitivity reaction.  

Encourage the patient to complete the antibiotic course in the same dose and frequency as the healthcare provider has prescribed in order for effective treatment and results to be obtained.   

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