n-penicillinase producing strains) anthrax bacillus anthracis actinomycosis (cervico-facial disease and thoracic and abdominal disease) actinomyces israelii 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 rhusiopathiae 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) penicillin g is not the drug of choice in the treatment of gram-negative bacillary infections. gram-negative bacillary organisms ( i.e . enterobacteriaceae) to reduce the development of drug-resistant bacteria and maintain 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.

is (agep) have been reported in patients taking beta-lactam antibiotics. when scar is suspected, penicillin g potassium for injection, usp should be discontinued immediately and an alternative treatment should be considered. clostridium difficile associated diarrhea clostridium difficile associated diarrhea (cdad) has been reported with use of nearly all antibacterial agents, including penicillin g potassium for injection, usp, and may range in severity from mild diarrhea to fatal colitis. treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of c. difficile . c. difficile produces toxins a and b which contribute to the development of cdad. hypertoxin producing strains of c. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. cdad must be considered in all patients who present with diarrhea following antibiotic use. careful medical history is necessary since cdad has been reported to occur over two months after the administration of antibacterial agents. if cdad is suspected or confirmed, ongoing antibiotic use not directed against c. difficile may need to be discontinued. appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of c. difficile , and surgical evaluation should be instituted as clinically indicated.

junction with antibiotic therapy. prescribing penicillin g potassium for injection, usp in the absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

half-life, penicillin g is administered in divided doses, usually every 4–6 hours with the exception of meningococcal meningitis/septicemia, i.e ., every 2 hours. ) thoracic and abdominal disease 10 to 20 million units/day( ) clostridial infections botulism (adjunctive therapy to antitoxin) 20 million units/day( ) gas gangrene (debridement and/or surgery as indicated) tetanus (adjunctive therapy to human tetanus immune globulin) diphtheria (adjunctive therapy to antitoxin and for the prevention of the carrier state) 2 to 3 million units/day in divided doses for 10–12 days( ) erysipelothrix endocarditis 12 to 20 million units/day for 4–6 weeks( ) fusospirochetosis (severe infections of the oropharynx [vincent's], lower respiratory tract and genital area) 5 to 10 million units/day( ) listeria infections meningitis 15 to 20 million units/day for 2 weeks( ) endocarditis 15 to 20 million units/day for 4 weeks( ) pasteurella infections including bacteremia and meningitis 4 to 6 million units/day for 2 weeks( ) haverhill fever; rat-bite fever 12 to 20 million units/day for 3–4 weeks( ) disseminated gonococcal infections, such as meningitis, endocarditis, arthritis, etc., caused by penicillin – susceptible organisms 10 million units/day( ); duration depends on the type of infection syphilis (neurosyphilis) 12 to 24 million units/day, as 2–4 mu every 4 hours for 10–14 days; many experts recommend additional therapy with benzathine pcn g 2.4 mu im weekly for 3 doses after completion of iv therapy meningococcal meningitis and/or septicemia 24 million units/day as 2 million units every 2 hours pediatric patients this product should not be administered to patients requiring less than one million units per dose (see precautions-pediatric use ). clinical indication dosage serious infections, such as pneumonia and endocarditis, due to susceptible strains of streptococci (including s. pneumoniae ) and meningococcus 150,000–300,000 units/kg/day divided in equal doses every 4–6 hours; duration depends on infecting organism and type of infection meningitis caused by susceptible strains of pneumococcus and meningococcus 250,000 units/kg/day divided in equal doses every 4 hours for 7–14 days depending on the infecting organism (maximum dose of 12–20 million units/day) disseminated gonococcal infections (penicillin-susceptible strains) weight less than 45 kg: arthritis 100,000 units/kg/day in 4 equally divided doses for 7–10 days meningitis 250,000 units/kg/day in equal doses every 4 hours for 10–14 days endocarditis 250,000 units/kg/day in equal doses every 4 hours for 4 weeks arthritis, meningitis, endocarditis weight 45 kg or greater: 10 million units/day in equally divided doses with the duration of therapy depending on the type of infection syphilis (congenital and neurosyphilis) after the newborn period 200,000–300,000 units/kg/day (administered as 50,000 units/kg every 4–6 hours) for 10–14 days diphtheria (adjunctive therapy to antitoxin and for prevention of the carrier state) 150,000–250,000 units/kg/day in equal doses every 6 hours for 7–10 days rat-bite fever; haverhill fever (with endocarditis caused by s. moniliformis ) 150,000–250,000 units/kg/day in equal doses every 4 hours for 4 weeks renal impairment penicillin g is relatively nontoxic, and dosage adjustments are generally required only in cases of severe renal impairment. the recommended dosage regimens are as follows: creatinine clearance less than 10 ml/min/1.73 m 2 ; administer a full loading dose (see recommended dosages in the tables above) followed by one-half of the loading dose every 8–10 hours. uremic patients with a creatinine clearance greater than 10 ml/min/1.73 m 2 ; administer a full loading dose (see recommended dosages in the tables above) followed by one-half of the loading dose every 4–5 hours. additional dosage modification should be made in patients with hepatic disease and renal impairment. for most acute infections, treatment should be continued for at least 48 to 72 hours after the patient becomes asymptomatic. antibiotic therapy for group a β-hemolytic streptococcal infections should be maintained for at least 10 days to reduce the risk of rheumatic fever. parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit. reconstitution the following table shows the amount of solvent required for solution of various concentrations: approx. desired concentration (units/ml) volume (ml) solvent for vial of 5,000,000 units infusion only volume (ml) solvent for vial of 20,000,000 units 50,000 – – 100,000 – – 250,000 18.2 75.0 500,000 8.2 33.0 1,000,000 3.2 11.5 when the required volume of solvent is greater than the capacity of the vial, the penicillin can be dissolved by first injecting only a portion of the solvent into the vial, then withdrawing the resultant solution and combining it with the remainder of the solvent in a larger sterile container. buffered pfizerpen (penicillin g potassium) for injection is highly water soluble. it may be dissolved in small amounts of water for injection, or sterile isotonic sodium chloride solution for parenteral use. all solutions should be stored in a refrigerator. when refrigerated, penicillin solutions may be stored for seven days without significant loss of potency. buffered pfizerpen for injection may be given intramuscularly or by continuous intravenous drip for dosages of 500,000, 1,000,000, or 5,000,000 units. it is also suitable for intrapleural, intraarticular, and other local instillations. the 20,000,000 unit dosage may be administered by intravenous infusion only. (1) intramuscular injection keep total volume of injection small. the intramuscular route is the preferred route of administration. solutions containing up to 100,000 units of penicillin per ml of diluent may be used with a minimum of discomfort. greater concentration of penicillin g per ml is physically possible and may be employed where therapy demands. when large dosages are required, it may be advisable to administer aqueous solutions of penicillin by means of continuous intravenous drip. (2) continuous intravenous drip determine the volume of fluid and rate of its administration required by the patient in a 24 hour period in the usual manner for fluid therapy, and add the appropriate daily dosage of penicillin to this fluid. for example, if an adult patient requires 2 liters of fluid in 24 hours and a daily dosage of 10 million units of penicillin, add 5 million units to 1 liter and adjust the rate of flow so the liter will be infused in 12 hours. (3) intrapleural or other local infusion if fluid is aspirated, give infusion in a volume equal to ¼ or ½ the amount of fluid aspirated, otherwise, prepare as for intramuscular injection. (4) intrathecal use the intrathecal use of penicillin in meningitis must be highly individualized. it should be employed only with full consideration of the possible irritating effects of penicillin when used by this route. the preferred route of therapy in bacterial meningitides is intravenous, supplemented by intramuscular injection. parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. sterile solution may be left in refrigerator for one week without significant loss of potency.

o penicillin may have occurred via trace amounts present in milk or vaccines. two types of allergic reactions to penicillin are noted clinically – immediate and delayed. immediate reactions usually occur within 20 minutes of administration and range in severity from urticaria and pruritus to angioneurotic edema, laryngospasm, bronchospasm, hypotension, vascular collapse and death (see warnings ). such immediate anaphylactic reactions are very rare and usually occur after parenteral therapy, but a few cases of anaphylaxis have been reported following oral therapy. another type of immediate reaction, an accelerated reaction, may occur between 20 minutes and 48 hours after administration and may include urticaria, pruritus, fever and, occasionally, laryngeal edema. delayed reactions to penicillin therapy usually occur within 1–2 weeks after initiation of therapy. manifestations include serum sickness-like symptoms, i.e ., fever, malaise, urticaria, myalgia, arthralgia, abdominal pain and various skin rashes, ranging from maculopapular eruptions to exfoliative dermatitis. contact dermatitis has been observed in individuals who prepare penicillin solutions. gastrointestinal system pseudomembranous colitis has been reported with the onset occurring during or after penicillin g treatment. nausea, vomiting, stomatitis, black or hairy tongue, and other symptoms of gastrointestinal irritation may occur, especially during oral therapy. hematologic system reactions include neutropenia, which resolves after penicillin therapy is discontinued; coombs-positive hemolytic anemia, an uncommon reaction, occurs in patients treated with intravenous penicillin g in doses greater than 10 million units/day and who have previously received large doses of the drug; and with large doses of penicillin, a bleeding diathesis can occur secondary to platelet dysfunction. metabolic penicillin g potassium, usp (1 million units contains 1.7 meq of potassium ion) may cause serious and even fatal electrolyte disturbances, i.e ., hyperkalemia, when given intravenously in large doses. nervous system neurotoxic reactions including hyperreflexia, myoclonic twitches, seizures and coma have been reported following the administration of massive intravenous doses, and are more likely in patients with impaired renal function. urogenital system renal tubular damage and interstitial nephritis have been associated with large intravenous doses of penicillin g. manifestations of this reaction may include fever, rash, eosinophilia, proteinuria, eosinophiluria, hematuria and a rise in serum urea nitrogen. discontinuation of penicillin g results in resolution in the majority of patients. local reactions phlebitis and thrombophlebitis may occur, and pain at the injection site has been reported with intravenous administration. to report suspected adverse events, contact pfizer inc. at 1-800-438-1985 or fda at 1-800-fda-1088 or http://www.fda.gov/ for voluntary reporting of adverse reactions.

e infections in individuals with normal kidney function. in neonates and young infants, and in individuals with impaired kidney function, excretion is considerably delayed. 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 3–5 minutes, the mean serum concentrations were 400 mcg/ml, 273 mcg/ml and 3.0 mcg/ml at 5–6 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 β-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 31–50 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 58–85% 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 in 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 2–6%. 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 β-phase serum half-life of penicillin g is prolonged. β-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 exerts a bactericidal action against penicillin-susceptible microorganisms during the stage of active multiplication. it acts through the inhibition of biosynthesis of cell wall peptidoglycan rendering the cell wall osmotically unstable. it is not active against the penicillinase-producing bacteria, which include many strains of staphylococci or against organisms resistant to beta-lactams because of alterations in the penicillin-binding proteins, such as methicillin-resistant staphylococci. penicillin g is highly active in vitro against streptococci (groups a, b, c, g, h, l, and m), and neisseria meningitidis . other organisms susceptible to penicillin g are n. gonorrhoeae , corynebacterium diphtheriae , bacillus anthracis , clostridium spp, actinomyces species, " spirillum minus ", streptobacillus moniliformis , listeria monocytogenes and leptospira spp; treponema pallidum is extremely sensitive to the bactericidal action of penicillin g. 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 spp. and shigella spp.; 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 .

ith or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. if this occurs, patients should contact their physician as soon as possible.