Home Drug Guide Penicillin G Sodium

Drug Guide

Generic Name

Penicillin G Sodium

Brand Names Crystapen, Pfizpen

Classification

Therapeutic: Antibiotic, Beta-lactam

Pharmacological: Penicillin antibiotic

FDA Approved Indications

Infections caused by susceptible bacteria, including streptococcal infections, meningococcal infections, syphilis, and some gram-positive and gram-negative bacteria

Mechanism of Action

Penicillin G sodium inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, leading to cell lysis and death.

Dosage and Administration

Adult: Dosage varies based on infection severity and site; typically, 2-24 million units per day divided into doses.

Pediatric: Dosage based on weight and age; usual doses range from 50,000 to 100,000 units/kg/day divided into doses.

Geriatric: Adjust dose based on renal function, caution due to increased risk of toxicity.

Renal Impairment: Reduce dosage proportionally to renal function; monitor renal function regularly.

Hepatic Impairment: No specific dose adjustment necessary, but monitor hepatic function as needed.

Pharmacokinetics

Absorption: Poor oral absorption; administered parenterally (IV or IM).

Distribution: Widely distributed in body fluids and tissues, including CSF when meninges are inflamed.

Metabolism: Minimal hepatic metabolism.

Excretion: Primarily excreted unchanged by the kidneys via glomerular filtration and tubular secretion.

Half Life: Approximately 30 minutes to 1 hour.

Contraindications

Known hypersensitivity to penicillins or other beta-lactam antibiotics.

Precautions

History of allergy, asthma, or atopy; renal impairment; monitor for allergic reactions.

Adverse Reactions - Common

Allergic reactions (rash, anaphylaxis) (Uncommon)
Pain at IM injection site (Common)

Adverse Reactions - Serious

Anaphylactic reactions (Rare)
Seizures (Rare in high doses or in renal impairment)
Hemolytic anemia (Rare)

Drug-Drug Interactions

Probenecid (delays renal excretion), Aminoglycosides (synergistic nephrotoxicity), Anticoagulants (may enhance effects)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Assess for allergy history, renal function, and infection response.

Diagnoses:

Impaired tissue perfusion related to infection.
Risk for allergic reaction.

Implementation: Administer IV or IM as prescribed; monitor for allergic reactions; ensure hydration to promote renal excretion.

Evaluation: Monitor infection signs, renal function, and allergy symptoms regularly.

Patient/Family Teaching

Report signs of allergic reactions immediately.
Complete the full course of therapy.
Inform about potential allergic reactions and allergic history.
Maintain adequate hydration.

Special Considerations

Black Box Warnings:

Severe allergic reactions, including anaphylaxis, especially in individuals with history of penicillin allergy.

Genetic Factors: None established.

Lab Test Interference: May cause false-positive tests for glucose in urine using Benedict's or Fehling's solution.

Overdose Management

Signs/Symptoms: Seizures, neurotoxicity, gastrointestinal disturbance.

Treatment: Supportive care; hemodialysis may be considered in severe cases.

Storage and Handling

Storage: Store at controlled room temperature, 20°C to 25°C (68°F to 77°F).

Stability: Stable when unopened; reconstituted solutions should be used promptly or stored as per manufacturer's instructions.