|PENICILLIN G POTASSIUM
PENICILLIN G SODIUM
Classifications: beta-lactam antibiotic; natural penicillin; Therapeutic: antibiotic; beta-lactam
Pregnancy Category: B
1,000,000 units, 5,000,000 units, 10,000,000 units, 20,000,000 units vials; 1,000,000 units/50 mL, 2,000,000 units/50 mL 3,000,000 units/50 mL injection
Acid-labile, penicillinase-sensitive, natural penicillin. Antimicrobial spectrum is relatively narrow compared to that of
the semisynthetic penicillins. Acts by interfering with synthesis of mucopeptides essential to formation and integrity of
bacterial cell wall. Action is inhibited by penicillinase.
Highly active against gram-positive cocci (e.g., non-penicillinase-producing Staphylococcus, Streptococcus groups) and gram-negative cocci. Also effective against gram-positive bacilli and gram-negative bacilli. Penicillin G
is effective against some strains of Salmonella and Shigella and spirochetes.
Moderate to severe systemic infections caused by penicillin-sensitive microorganisms. Certain staphylococcal infections;
streptococcal infections. Also used as prophylaxis in patients with rheumatic or congenital heart disease. Since oral preparations
are absorbed erratically and thus must be given in comparatively high doses, this route is generally used only for mild
or stabilized infections or long-term prophylaxis.
Hypersensitivity to any of the penicillins or cephalosporins; administration of oral drug to patients with severe infections;
nausea, vomiting, hypermotility, gastric dilatation; cardiospasm. Use of penicillin G sodium in patients on sodium restriction.
History of or suspected allergy (asthma, eczema, hay fever, hives); history of allergy to cephalosporins; GI disorders;
kidney or liver dysfunction, myasthenia gravis, epilepsy, neonates, young infants; pregnancy (category B). Use during lactation
may lead to sensitization of infants.
Route & Dosage
|Moderate to Severe Infections
Adult: IV/IM 224 million U divided q4h
Child: IV/IM 250,000400,000 U/kg divided q4h
Note: Check whether physician has prescribed penicillin G potassium or sodium. Intramuscular
- Do not use the 20,000,000 unit dosage form for IM injection.
- Reconstitute for IM: Loosen powder by shaking bottle before adding diluent (sterile water for injection or sterile NS).
Keep the total volume to be injected small. Solutions containing up to 100,000 units/mL cause the least discomfort. Adding
10 mL diluent to the 1,000,000 unit vial = 100,000 units/mL. Shake well to dissolve.
- Select IM site carefully. IM injection is made deep into a large muscle mass. Inject slowly. Rotate injection sites.
PREPARE: Intermittent/Continuous: Reconstitute as for IM injection then withdraw the required dose and add to 1001000 mL of D5W or NS IV solution, depending
on length of each infusion.
ADMINISTER: Intermittent/Continuous: Give intermittent infusion over at least 1 h and continuous infusion at a rate required to infuse the daily dose in 24 h.
With high doses, IV penicillin G should be administered slowly to avoid electrolyte imbalance from potassium or sodium content.
Physician will often prescribe specific flow rate.
INCOMPATIBILITIES Solution/additive: Dextran 40, fat emulsion, aminophylline, amphotericin B, cephalothin, chlorpromazine, dopamine, hydroxyzine, metaraminol, metoclopramide, pentobarbital, prochlorperazine, promazine, sodium bicarbonate, tetracycline, thiopental.
- Store dry powder (for parenteral use) at room temperature. After reconstitution (initial dilution), store solutions for
1 wk under refrigeration. Intravenous infusion solutions containing penicillin G are stable at room temperature for at least
Adverse Effects (≥1%) Body as a Whole:
Coughing, sneezing, feeling of uneasiness; systemic anaphylaxis,
fever, widespread increase in capillary permeability and vasodilation with resulting edema (mouth, tongue, pharynx, larynx), laryngospasm, malaise
sickness (fever, malaise
, pruritus, urticaria, lymphadenopathy, arthralgia
, angioedema of face and extremities,
prostration, eosinophilia), SLE-like syndrome
, Injection site reactions (pain, inflammation, abscess, phlebitis),
superinfections (especially with Candida
and gram-negative bacteria), neuromuscular irritability (twitching, lethargy, confusion, stupor, hyperreflexia, multifocal
myoclonus, localized or generalized seizures, coma
Hypotension, circulatory collapse,
cardiac arrhythmias, cardiac arrest. GI:
, severe abdominal cramps, nausea, epigastric distress, diarrhea
, flatulence, dark discoloration of tongue,
sore mouth or tongue. Urogenital: Interstitial
nephritis, Loeffler's syndrome
, vasculitis. Hematologic:
Hyperkalemia (penicillin G potassium); hypokalemia, alkalosis, hypernatremia, CHF (penicillin G sodium). Respiratory:
Itchy palms or axilla, pruritus, urticaria,
flushed skin, delayed skin rashes
ranging from urticaria to exfoliative dermatitis, Stevens-Johnson syndrome
, fixed-drug eruptions, contact dermatitis.
Diagnostic Test Interference
Blood grouping and compatibility tests: possible interference associated with penicillin doses greater than 20 million units daily. Urine glucose: massive doses of penicillin may cause false-positive test results with Benedict's solution and possibly Clinitest but not with glucose oxidase methods (e.g., Clinistix, Diastix, TesTape). Urine protein: massive doses of penicillin can produce false-positive results when turbidity measures are used (e.g., acetic acid and heat, sulfo-salicylic acid); Ames reagent reportedly not affected. Urinary PSP excretion tests: false decrease in urinary excretion of PSP. Urinary steroids: large IV doses of penicillin may interfere with accurate measurement of urinary 17-OHCS (Glenn-Nelson technique not affected).
elimination; penicillin G may decrease efficacy
of oral contraceptives
decreases penicillin absorption; potassium-sparing diuretics
may cause hyperkalemia with penicillin G potassium. Food:
Food increases breakdown in stomach.
1530 min IM. Distribution:
Widely distributed; good CSF concentrations with inflamed meninges; crosses placenta; distributed in breast milk. Metabolism:
1630% metabolized. Elimination:
60% in urine within 6 h. Half-Life:
Assessment & Drug Effects
- Obtain an exact history of patient's previous exposure and sensitivity to penicillins and cephalosporins and other allergic
reactions of any kind prior to treatment with penicillin.
- Hypersensitivity reactions are more likely to occur with parenteral penicillin but may also occur with the oral drug. Skin
rash is the most common type allergic reaction and should be reported promptly to physician.
- Lab tests: Perform C&S tests prior to initiation of therapy; treatment may be started before results are known. Evaluate
renal, hepatic, and hematologic systems at regular intervals in patients on high-dose therapy. Additionally, check electrolyte
balance periodically in patients receiving high parenteral doses.
- Observe all patients closely for at least 30 min following administration of parenteral penicillin. The rapid appearance
of a red flare or wheal at the IM or IV injection site is a possible sign of sensitivity. Also suspect an allergic reaction
if patient becomes irritable, has nausea and vomiting, breathing difficulty, or sudden fever. Report any of the foregoing
to physician immediately.
- Be aware that reactions to penicillin may be rapid in onset or may not appear for days or weeks. Symptoms usually disappear
fairly quickly once drug is stopped, but in some patients may persist for 5 d or more and require hospitalization for treatment.
- Allergy to penicillin is unpredictable. It has occurred in patients with a negative history of penicillin allergy and also
in patients with no known prior contact with penicillin (sensitization may have occurred from penicillin used commercially
in foods and beverages).
- Be alert for neuromuscular irritability in patients receiving parenteral penicillin in excess of 20 million U/d who have
renal insufficiency, hyponatremia, or underlying CNS disease, notably myasthenia gravis or epilepsy. Seizure precautions
are indicated. Symptoms usually begin with twitching, especially of face and extremities.
- Monitor I&O, particularly in patients receiving high parenteral doses. Report oliguria, hematuria, and changes in I&O ratio.
Consult physician regarding optimum fluid intake. Dehydration increases the concentration of drug in kidneys and can cause
renal irritation and damage.
- Observe closely for signs of toxicity: Neonates, young infants, the older adult, and patients with impaired kidney function
receiving high-dose penicillin therapy. Urinary excretion of penicillin is significantly delayed in these patients.
- Observe patients on high-dose therapy closely for evidence of bleeding, and bleeding time should be monitored. (In high doses,
penicillin interferes with platelet aggregation.)
Patient & Family Education
- Understand that hypersensitivity reaction may be delayed. Report skin rashes, itching, fever, malaise, and other signs of
a delayed reaction to physician immediately (see ADVERSE EFFECTS).
- Notify physician if following symptoms appear when taking penicillin for treatment of syphilis (i.e., Jarisch-Herxheimer
reaction occurs 824 h after treatment): Headache, chills, fever, myalgia, arthralgia, malaise, and worsening of syphilitic
skin lesions. Reaction is usually self-limiting. Check with physician if symptoms do not improve within a few days or get
- Report S&S of superinfection (see Appendix F).
- Understand importance of medical follow-up; present evidence suggests that glomerulonephritis, a possible complication of
streptococcal infection, may not be prevented by penicillin.