Penicillin G Potassium

PENICILLIN G POTASSIUM- penicillin g potassium injection, powder, for solution
Sandoz Inc

Rx Only

BUFFERED

To reduce the development of drug-resistant bacteria and maintain the effectiveness of penicillin G potassium and other antibacterial drugs, penicillin G potassium should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

DESCRIPTION

Buffered penicillin G potassium for injection, USP is sterile penicillin G potassium powder for reconstitution. It is an antibacterial agent intended for intravenous or intramuscularly use.

Chemically, penicillin G potassium is monopotassium (2S,5R,6R)-3,3-dimethyl-7-oxo-6-(2-phenylacetamido)-4-thia-1-azabicyclo (3.2.0) heptane-2-carboxylate, and has the following chemical structure:

chemical-structure
(click image for full-size original)

Molecular Formula: C16 H17 KN2 O4 S

Molecular Weight: 372.48

Penicillin G potassium, a water soluble benzylpenicillin, is a white to almost white crystalline powder which is almost odorless and/or after reconstitution a colorless solution. The pH of freshly constituted solutions usually ranges from 6 to 8.5. Sodium citrate and citric acid have been added as a buffer.

Buffered penicillin G potassium for injection, USP is supplied in vials equivalent to 1,000,000 units (1 million units), 5,000,000 units (5 million units), or 20,000,000 units (20 million units) of penicillin G as the potassium salt. Each million unit contains approximately 7.9 milligrams of sodium (0.34 mEq) and 65.6 milligrams of potassium (1.68 mEq).

CLINICAL PHARMACOLOGY

After an intravenous infusion of penicillin G, peak serum concentrations are attained immediately after completion of the infusion. In a study of ten patients administered a single 5 million unit dose of penicillin G intravenously over 3 to 5 minutes, the mean serum concentrations were 400 mcg/mL, 273 mcg/mL and 3 mcg/mL at 5 to 6 minutes, 10 minutes and 4 hours after completion of the injection, respectively. In a separate study, five healthy adults were administered one million units of penicillin G intravenously, either as a bolus over 4 minutes or as an infusion over 60 minutes. The mean serum concentration eight minutes after completion of the bolus was 45 mcg/mL and eight minutes after completion of the infusion was 14.4 mcg/mL.

The mean beta-phase serum half-life of penicillin G administered by the intravenous route in ten patients with normal renal function was 42 minutes, with a range of 31 to 50 minutes.

The clearance of penicillin G in normal individuals is predominantly via the kidney. The renal clearance, which is extremely rapid, is the result of glomerular filtration and active tubular transport, with the latter route predominating. Urinary recovery is reported to be 58 to 85% of the administered dose. Renal clearance of penicillin is delayed in premature infants, neonates and in the elderly due to decreased renal function. The serum half-life of penicillin G correlates inversely with age and clearance of creatinine and ranges from 3.2 hours in infants 0 to 6 days of age to 1.4 hours in infants 14 days of age or older.

Nonrenal clearance includes hepatic metabolism and, to a lesser extent, biliary excretion. The latter routes become more important with renal impairment.

Probenecid blocks the renal tubular secretion of penicillin. Therefore, the concurrent administration of probenecid prolongs the elimination of penicillin G and, consequently, increases the serum concentrations.

Penicillin G is distributed to most areas of the body including lung, liver, kidney, muscle, bone and placenta. In the presence of inflammation, levels of penicillin in abscesses, middle ear, pleural, peritoneal and synovial fluids are sufficient to inhibit most susceptible bacteria. Penetration into the eye, brain, cerebrospinal fluid (CSF) or prostate is poor in the absence of inflammation. With inflamed meninges, the penetration of penicillin G into the CSF improves, such that the CSF/serum ratio is 2 to 6%. Inflammation also enhances its penetration into the pericardial fluid. Penicillin G is actively secreted into the bile resulting in levels at least 10 times those achieved simultaneously in serum. Penicillin G penetrates poorly into human polymorphonuclear leukocytes.

In the presence of impaired renal function, the beta-phase serum half-life of penicillin G is prolonged. beta-phase serum half-lives of one to two hours were observed in azotemic patients with serum creatinine concentrations <3 mg/100 mL and ranged as high as 20 hours in anuric patients. A linear relationship, including the lowest range of renal function, is found between the serum elimination rate constant and renal function as measured by creatinine clearance.

In patients with altered renal function, the presence of hepatic insufficiency further alters the elimination of penicillin G. In one study, the serum half-lives in two anuric patients (excreting <400 mL urine/day) were 7.2 and 10.1 hours. A totally anuric patient with terminal hepatic cirrhosis had a penicillin half-life of 30.5 hours, while another patient with anuria and liver disease had a serum half-life of 16.4 hours. The dosage of penicillin G should be reduced in patients with severe renal impairment, with additional modifications when hepatic disease accompanies the renal impairment.

Hemodialysis has been shown to reduce penicillin G serum levels.

Microbiology

Penicillin G is bactericidal against penicillin-susceptible microorganisms during the stage of active multiplication. It acts by inhibiting biosynthesis of cell-wall mucopeptide. It is not active against the penicillinase-producing bacteria, which include many strains of staphylococci. Penicillin G is highly active in vitro against staphylococci (except penicillinase-producing strains), streptococci (groups A, B, C, G, H, L and M), pneumococci and Nelsseria meningitidis. Other organisms susceptible in vitro to penicillin G are Nelsseria gonorrhoeae, Corynebacterium diphtheriae, Bacillus anthracis, clostridia, Actinomyces species, Spirillum minus, Streptobacillus monillformis, Listeria monocytogenes, and leptospira ; Treponema pallidum is extremely susceptible.

Some species of gram-negative bacilli were previously considered susceptible to very high intravenous doses of penicillin G (up to 80 million units/day) including some strains of Escherichia coli, Proteus mirabilis, salmonella, shigella, Enterobacter aerogenes (formerly Aerobacter aerogenes) and Alcaligenes faecalis. Penicillin G is no longer considered a drug of choice for infections caused by these organisms.

Susceptibility Testing

For specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by FDA for this drug, please see: https://www.fda.gov/STIC.

INDICATIONS AND USAGE

Therapy

Buffered penicillin G potassium for injection is indicated in the treatment of serious infections caused by susceptible strains of the designated microorganisms in the conditions listed below. Appropriate culture and susceptibility tests should be done before treatment in order to isolate and identify organisms causing infection and to determine their susceptibility to penicillin G. Therapy with Buffered penicillin G potassium for injection may be initiated before results of such tests are known when there is reason to believe the infection may involve any of the organisms listed below, however, once these results become available, appropriate therapy should be continued.

CLINICAL INDICATION INFECTING ORGANISM

Septicemia, empyema, pneumonia, pericarditis, endocarditis, meningitis

Streptococcus pyogenes (group A beta-hemolytic streptococcus), other beta-hemolytic streptococci including groups C, H, G, L and M, Streptococcus pneumoniae and Staphylococcus species (non-penicillinase producing strains)

Anthrax

Bacillus anthracis

Actinomycosis (cervicofacial disease and thoracic and abdominal disease)

Actinomyces Israelil

Botulism (adjunctive therapy to antitoxin), gas gangrene, and tetanus (adjunctive therapy to human tetanus immune globulin)

Clostridium species

Diphtheria (adjunctive therapy to antitoxin and prevention of the carrier state)

Corynebacterium diphtheriae

Erysipelothrix endocarditis

Erysipelothrix rhusiopthiae

Fusospirochetosis (severe infections of the oropharynx [Vincent’s], lower respiratory tract and genital area)

Fusobacterium species and spirochetes

Listeria infections including meningitis and endocarditis

Listeria monocytogenes

Pasteurella infections including bacteremia and meningitis

Pasteurella multocida

Haverhill fever

Streptobacillus moniliformis

Rat-bite fever

Spirillum minus or Streptobacillus moniliformis

Disseminated gonococcal infections

Neisseria gonorrhoeae (penicillin-susceptible)

Syphilis (congenital and neurosyphilis)

Treponema pallidum

Meningococcal meningitis and/or septicemia

Neisseria meningitidis

Gram-negative bacillary infections (bacteremias)

Escherichia coli, Enterobacter aerogenes, Alcaligenes faecalis, salmonella, shigella and Proteus mirabilis, Penicillin G is not the drug of choice in the treatment of gram-negative bacillary infections.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of penicillin G potassium and other antibacterial drugs, penicillin G potassium should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

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