AMOXICILLIN
  • AMOXICILLIN

  • QTY 30 • 500 MG • Capsule • Near 77381

AMOXICILLIN (a mox i SIL in) is a penicillin antibiotic. It is used to treat certain kinds of bacterial infections. It will not work for colds, flu, or other viral infections.

AMOXICILLIN Pediatric Monographs
  • General Administration Information
    For storage information, see the specific product information within the How Supplied section.

    Route-Specific Administration

    Oral Administration
    Oral Solid Formulations
    -Chewable tablets only: Should be chewed before swallowing; do not swallow whole.
    -Capsules, chewable tablets, and immediate-release tablets: May be given without regard to meals. The 400 mg chewable tablet and the 875 mg tablet have been studied only when administered at the start of a light meal.
    -Extended-release tablets: Take within 1 hour of finishing a meal. Do not chew or crush.

    Oral Liquid Formulations
    -In general, amoxicillin oral suspension may be given without regard to meals. The 400 mg suspension has been studied only when administered at the start of a light meal.
    -Shake well prior to each administration. Measure dosage with calibrated spoon, cup, or oral syringe.
    -The measured dose of suspension may be added to formula, milk, fruit juice, water, ginger ale, or cold drinks for administration. These preparations should be administered immediately and consumed in their entirety to ensure all of the dose is received.

    Reconstitution method for oral suspension:
    -Review the reconstitution instructions for the particular product and package size, as the amount of water required for reconstitution varies from manufacturer to manufacturer.
    -Prior to reconstitution, tap the bottle several times to loosen the powder. Add approximately 1/3 of the total amount of water as instructed by the manufacturer and shake well. Add the remainder of the water and shake well.
    -Storage after reconstitution: Store under refrigeration (preferred) or at controlled room temperature for up to 14 days. Discard any unused portion after 14 days.

    Hypersensitivity reactions are among the most frequently reported side effects of the penicillins, including with amoxicillin. Penicillin allergy has been reported in up to 20% of patients; however, around 90% of reported allergies are incorrectly reported and patients lack penicillin-specific IgE antibodies. The actual prevalence of penicillin allergy is likely no greater than 5%. These reactions may include serum sickness, hypersensitivity-related rashes, and/or anaphylactoid reactions including anaphylactic shock. Angioedema has also been reported with penicillins. Hypersensitivity-related rashes include bullous rash, erythema multiforme, exfoliative dermatitis, maculopapular rash with erythema, toxic epidermal necrolysis, Stevens-Johnson syndrome, hypersensitivity vasculitis, and urticaria. Contact dermatitis and rash (unspecified) may occur in 4-8% of patients receiving penicillins and may be idiopathic in nature. The incidence of rash secondary to amoxicillin seems to be higher in patients with a history of allergy, asthma, hay fever, or urticaria. If a hypersensitivity reaction occurs, discontinue amoxicillin and institute appropriate therapy.

    Hematologic effects seen with penicillins, such as amoxicillin, include eosinophilia, anemia (including hemolytic anemia), thrombocytopenia, thrombotic thrombocytopenic purpura (TTP), agranulocytosis, and leukopenia. These adverse hematologic effects are generally reversible after discontinuation of the penicillin. Platelet dysfunction, prolonged bleeding time, and prolongation of APTT have been reported in patients receiving beta-lactams.

    Amoxicillin has been associated with acute generalized exanthematous pustulosis (AGEP). The non follicular, pustular, erythematous rash starts suddenly and is associated with fever above 38 degrees C. Drugs are the main cause of AGEP. A period of 2-3 weeks after an inciting drug exposure appears necessary for a first episode of AGEP. Unintentional reexposure may cause a second episode within 2 days.

    Nausea, vomiting, and diarrhea have been reported with penicillins, such as amoxicillin. In a tonsillitis and pharyngitis study, 302 adult and pediatric patients (>= 12 years) were treated with the extended release oral tablet. Reports of diarrhea (1.7%), nausea (1.3%), vomiting (0.7%), and abdominal pain (0.3%) were all similar to those reported with the comparator drug. Antibiotic-associated colitis, also known as pseudomembranous colitis can occur during use of or after discontinuance of amoxicillin, but this effect is rare. Tongue discoloration (black hairy tongue) has also been reported with amoxicillin.

    Superinfection can occur with amoxicillin therapy. Prolonged or repeated therapy in particular can result in overgrowth by nonsusceptible bacteria or fungi. If superinfections occur, discontinue amoxicillin and institute appropriate therapy. Mucocutaneous candidiasis may occur as oral candidiasis (i.e. thrush) or vaginal candidiasis. Vulvovaginal mycotic infections were reported in 2% of adult and pediatric patients (>= 12 years) receiving the extended release oral tablet during a tonsillitis and pharyngitis study (n=302).

    Headache is the most common CNS adverse effect associated with amoxicillin therapy. In a study of adult and pediatric patients (>= 12 years) receiving extended-release amoxicillin tablets for tonsillitis and pharyngitis (n = 302), 1% of patients reported headache. Other adverse events such as agitation, reversible hyperactivity, anxiety, convulsions (seizures), confusion, dizziness, insomnia, or other behavioral changes have been reported rarely. Seizures have been reported when large doses of penicillins were administered to patients with renal impairment. Appropriate dosage adjustments should be observed in these patients.

    Hepatic dysfunction has been reported as cholestatic jaundice, cholestasis, or acute cytolytic hepatitis. Other reported side effects of amoxicillin include elevated hepatic enzymes (e.g., moderate rises in AST and/or ALT); however, the clinical significance is not known.

    Tooth discoloration (brown, yellow, or gray staining) has been rarely reported with amoxicillin therapy. The majority of reports have been in children. In most cases, discoloration was reduced or eliminated by brushing or dental cleaning. A follow-up study accessing fluoride intake and amoxicillin use reported a possible link to amoxicillin-associated dental fluorosis affecting permanent teeth. After adjusting for fluoride intake and otitis media, the study noted a significant increase in the risk of fluorosis with amoxicillin therapy. The highest risk for fluorosis was noted with amoxicillin use in the first year of life, especially in early infancy (first 6 months).

    Crystalluria has also been reported in association with amoxicillin therapy.

    The Jarisch-Herxheimer reaction is a self-limiting systemic reaction that has been reported in the setting of spirochete infections, such as Lyme disease, syphilis, relapsing fever, and leptospirosis, after the initiation of antimicrobial therapy. It is characterized by fever, chills, myalgias, headache, exacerbation of cutaneous lesions, tachycardia, hyperventilation, vasodilation with flushing, and mild hypotension. Less commonly, symptoms may include meningitis, pulmonary failure, hepatic and renal dysfunction, myocardial injury, premature uterine contractions in pregnant patients, and worsening cerebral function as well as strokes and seizures. The reaction has been noted in up to 30% of patients with early Lyme disease. The timing of the reaction varies by underlying infection but typically presents within a few hours after the initiation of antibiotics. For Lyme disease, the reaction usually begins within 1 to 2 hours after starting therapy and disappears within 12 to 24 hours. The reaction after treatment in syphilis usually starts at 4 hours, peaks at 8 hours, and subsides by 16 hours whereas it starts at about 1 to 2 hours, peaks at 4 hours, and subsides by 8 hours after treatment in relapsing fever. The pathogenesis of this reaction is unknown but may be due to the release of spirochetal heat-stable pyrogen. Fluids and antipyretics can be used to alleviate symptoms and duration of the reaction if severe.

    Amoxicillin is a penicillin and is contraindicated in patients with a serious penicillin hypersensitivity or who have had a serious hypersensitivity reaction to other beta-lactam antibiotics. In general, amoxicillin should be used cautiously in patients with cephalosporin hypersensitivity or carbapenem hypersensitivity. These patients are more susceptible to hypersensitivity reactions during therapy with amoxicillin; the incidence of true cross-sensitivity has been estimated at roughly 3-7%. Patients with allergies or atopic conditions including asthma, eczema, hives (urticaria), or hay fever may have a greater risk for hypersensitivity reactions to penicillins.

    Use amoxicillin with caution in patients with renal impairment or renal failure as the drug is substantially eliminated via renal mechanisms. There are no dosing recommendations available for pediatric patients with renal impairment; however, dosage adjustments are recommended in adults with CrCl <= 30 ml/min. Do not use the extended release tablet in patients with CrCl <= 30 ml/min.

    Almost all antibacterial agents, including amoxicillin, have been associated with pseudomembranous colitis (antibiotic-associated colitis), which may range in severity from mild to life-threatening. In the colon, overgrowth of Clostridia may occur when normal flora is altered subsequent to antibacterial administration. The toxin produced by Clostridium difficile is a primary cause of pseudomembranous colitis. Consider pseudomembranous colitis as a potential diagnosis in patients presenting with diarrhea after antibacterial administration. Systemic antibiotics should be prescribed with caution to patients with inflammatory bowel disease such as ulcerative colitis or other GI disease. If diarrhea develops during therapy, discontinue the drug. After a diagnosis of pseudomembranous colitis, institute therapeutic measures. Practitioners should be aware that antibiotic-associated colitis can occur over 2 months or more after discontinuation of systemic antibiotic therapy; a careful medical history should be taken.

    Patients with phenylketonuria should be warned that some chewable tablets contain phenylalanine. The phenylalanine content varies with the manufacturer; consult the specific product labeling to determine phenylalanine content.

    According to the manufacturer, amoxicillin should not be used in patients with mononucleosis as a high incidence of skin rashes have been reported in these patients.

    While amoxicillin may be used to treat certain sexually transmitted diseases (STD), the drug may mask or delay the symptoms of incubating syphilis when given as part of an STD treatment regimen. All patients with a diagnosed or suspected STD should be tested for other STDs, which may include HIV, syphilis, and gonorrhea, at the time of diagnosis. Initiate appropriate therapy and perform follow-up testing as recommended based upon sexually transmitted disease diagnosis.

    Administration of amoxicillin may result in laboratory test interference. A false-positive reaction for glucose in the urine has been observed in patients receiving penicillins and using Benedict's solution, Fehling's solution, or Clinitest tablets for urine glucose testing. However, this reaction has not been observed with Tes-tape (glucose Enzymatic Test Strip, USP, Lilly) or Clinistix. Patients with diabetes mellitus who test their urine for glucose should use glucose tests based on enzymatic glucose oxidase reactions while on amoxicillin treatment. Antimicrobials are also known to suppress H. pylori; thus, ingestion of these agents within 4 weeks of performing diagnostic tests for H. pylori may lead to false negative results. At a minimum, instruct the patient to avoid the use of amoxicillin in the 4 weeks prior to the test.

    Description: Amoxicillin is an oral semisynthetic aminopenicillin similar to ampicillin. The aminopenicillins are not stable to beta-lactamases of either gram-positive or gram-negative bacteria. Amoxicillin is more stable to gastric acid than is penicillin and more bioavailable than oral ampicillin. Because of greater bioavailability, amoxicillin is associated with a lower incidence of diarrhea versus orally-administered ampicillin. Like ampicillin, amoxicillin has a broader spectrum of activity than penicillin, although the carboxy- and ureidopenicillins are much more active against gram-negative rods. Amoxicillin is first line therapy for acute otitis media in pediatric patients and is also commonly used to treat infections such as bronchitis, pneumonia, and bacterial cystitis caused by susceptible organisms. To increase the efficacy of amoxicillin against penicillin-resistant S. pneumoniae in otitis media or respiratory infections, higher dosage regimens (e.g., 80-90 mg/kg/day) are recommended for young children. Amoxicillin immediate-release formulations are FDA approved for use in pediatric patients as young as neonates; an extended-release formulation is FDA approved for use in children 12 years of age and older.

    Per the manufacturer, this drug has been shown to be active against most strains of the following microorganisms either in vitro and/or in clinical infections: Enterococcus faecalis, Escherichia coli, Haemophilus influenzae (beta-lactamase negative), Helicobacter pylori, Proteus mirabilis, Staphylococcus sp., Streptococcus agalactiae (group B streptococci), Streptococcus pneumoniae, Streptococcus pyogenes (group A beta-hemolytic streptococci)
    NOTE: The safety and effectiveness in treating clinical infections due to organisms with in vitro data only have not been established in adequate and well-controlled clinical trials.

    This drug may also have activity against the following microorganisms: Bacillus anthracis, Borrelia burgdorferi, Chlamydia trachomatis, Salmonella enterica serotype Typhi
    NOTE: Some organisms may not have been adequately studied during clinical trials; therefore, exclusion from this list does not necessarily negate the drug's activity against the organism.

    For the treatment of acute otitis media:
    NOTE: The American Academy of Pediatrics (AAP) does not recommend doses less than 80 mg/kg/day PO for the treatment of otitis media. Re-evaluate patients failing to respond within 48 to 72 hours. Amoxicillin; clavulanate is the preferred therapy for children who have received amoxicillin within the past 30 days, who have purulent conjunctivitis, or who have a history of recurrent acute otitis media unresponsive to amoxicillin.
    Oral dosage (immediate-release):
    Infants 1 to 3 months: 30 mg/kg/day PO divided every 12 hours is the general FDA-approved dosing. Young infants are less capable of responding to infection, and the clinical manifestations of infection can be subtle. Because of the increased risk for complications of an undiagnosed systemic infection, every young infant presenting with a fever should be carefully evaluated.
    Infants 4 to 5 months: 80 to 90 mg/kg/day PO divided every 12 hours for 10 days was recommended by experts as first-line therapy in previous guidelines; however, this age group is not addressed in the most current guidelines by the American Academy of Pediatrics (AAP). Although the FDA-approved dosage ranges from 20 to 45 mg/kg/day depending on the severity of infection, these low doses are not clinically recommended for the treatment of otitis media.
    Infants, Children, and Adolescents 6 months to 17 years: 80 to 90 mg/kg/day PO divided every 12 hours is first-line therapy. Treat all patients younger than 2 years and patients 2 years and older with severe disease for 10 days. For children 2 to 5 years with mild to moderate disease, a 7-day course is acceptable. For children 6 years and older with mild to moderate disease, a 5- to 7-day course is acceptable. Although the FDA-approved dosage ranges from 20 to 45 mg/kg/day PO depending on the severity of infection (Max: 500 mg/dose for every 8 hour dosing and 875 mg/dose for every 12 hour dosing), these low doses are not clinically recommended for the treatment of otitis media.

    For the treatment of upper respiratory tract infections (e.g., pharyngitis and tonsillitis) and skin and skin structure infections (e.g., cellulitis):
    Oral dosage (immediate-release):
    Neonates and Infants <= 3 months: 30 mg/kg/day PO given in divided doses every 12 hours.
    Infants > 3 months, Children, and Adolescents: 20 mg/kg/day PO in divided doses every 8 hours (Max: 250 mg/dose) or 25 mg/kg/day PO in divided doses every 12 hours (Max: 500 mg/dose) for mild to moderate infections and 40 mg/kg/day PO in divided doses every 8 hours (Max: 500 mg/dose) or 45 mg/kg/day PO in divided doses every 12 hours (Max: 875 mg/dose) for severe infections.
    -for the treatment of tonsillitis and/or pharyngitis secondary to Streptococcus pyogenes (i.e. primary rheumatic fever prophylaxis):
    Oral dosage (immediate-release):
    Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 500 mg/dose) PO twice daily for 10 days is recommended by the Infectious Diseases Society of America (IDSA). Alternatively, 50 mg/kg/dose PO once daily (Max: 1 g/dose) for 10 days is recommended by The American Heart Association (AHA) as an alternative to penicillin V. For ear/nose/throat infections in general, the FDA-approved dosage is 20 mg/kg/day PO in divided doses every 8 hours (Max: 250 mg/dose) or 25 mg/kg/day PO in divided doses every 12 hours (Max: 500 mg/dose) for mild to moderate infections and 40 mg/kg/day PO in divided doses every 8 hours (Max: 500 mg/dose) or 45 mg/kg/day PO in divided doses every 12 hours (Max: 875 mg/dose) for severe infections.
    Oral dosage (extended-release tablets):
    Children >= 12 years and Adolescents: 775 mg PO once daily, given within 1 hour of completing a meal, for 10 days. The American Heart Association (AHA) recommends amoxicillin extended-release as an alternative to penicillin V for rheumatic fever prophylaxis.
    -for the treatment of sinusitis:
    NOTE: Due to the high rates of H. influenzae and beta-lactamase-producing pathogens among upper respiratory tract infections in children, amoxicillin/clavulanate (and not amoxicillin alone) is recommended as first-line empiric therapy for acute bacterial sinusitis by the Infectious Disease Society of America (IDSA). However, the American Academy of Pediatrics (AAP) considers amoxicillin an option for children >= 2 years with uncomplicated disease in which antimicrobial resistance is not suspected.
    Oral dosage (immediate-release):
    Children < 2 years: Children < 2 years should be treated with amoxicillin; clavulanic acid, not amoxicillin alone.
    Children >= 2 years and Adolescents: According to the American Academy of Pediatrics (AAP), amoxicillin is the agent of choice for first-line therapy for uncomplicated bacterial sinusitis when antimicrobial resistance is not suspected. Children with moderate to severe disease, attending daycare, or who have recently been treated with antimicrobial therapy should receive high-dose amoxicillin; clavulanic acid.
    - 45 mg/kg/day PO in divided doses every 12 hours is the standard dose for children with uncomplicated disease that is mild to moderate in severity who do not attend daycare and who have not been treated with an antimicrobial agent in the previous 4 weeks.
    - 80-90 mg/kg/day (high-dose therapy) PO in divided doses every 12 hours (Max: 2 g/dose) is recommended for children in areas with high rates of S. pneumoniae resistance (> 10%, including intermediate- and high-level resistance).

    For the treatment of lower respiratory tract infections (LRTIs), including community-acquired pneumonia (CAP):
    -for the treatment of nonspecific lower respiratory tract infections (LRTIs):
    Oral dosage (immediate-release):
    Neonates and Infants 1 to 3 months: 30 mg/kg/day PO in divided doses every 12 hours.
    Infants, Children, and Adolescents 4 months to 17 years: 45 mg/kg/day PO in divided doses every 12 hours or 40 mg/kg/day PO in divided doses every 8 hours (Max: 1,750 mg/day).
    -for the treatment of community-acquired pneumonia (CAP):
    Oral dosage (immediate-release):
    Infants and Children 4 months to 12 years: 90 mg/kg/day PO in divided doses every 8 to 12 hours (Max: 4 g/day). Dividing 90 mg/kg/day into 3 doses/day increases the probability for reaching a clinical and microbiological cure to 90% compared with the same daily dose divided into 2 doses/day (65%) in patients with pneumococcal pneumonia (MIC of 2 mcg/mL). For less resistant pneumococcal strains (MIC of 0.5 mcg/mL), dividing 90 mg/kg/day into 2 doses will likely achieve a clinical and microbiological cure in more than 99% of children. Consider the addition of a macrolide for patients 5 years and older who do not have clinical, laboratory, or radiologic evidence to distinguish bacterial CAP from atypical CAP. Depending on the causative organism, definitive therapy may range from 45 to 100 mg/kg/day PO in divided doses.
    Adolescents: 90 mg/kg/day PO in divided doses every 8 to 12 hours (Max: 4 g/day) for 5 to 7 days. Dividing 90 mg/kg/day into 3 doses/day increases the probability for reaching a clinical and microbiological cure to 90% compared with the same daily dose divided into 2 doses/day (65%) in patients with pneumococcal pneumonia (MIC of 2 mcg/mL). For less resistant pneumococcal strains (MIC of 0.5 mcg/mL), dividing 90 mg/kg/day into 2 doses will likely achieve a clinical and microbiological cure in more than 99% of children. Consider the addition of a macrolide for patients 5 years and older who do not have clinical, laboratory, or radiologic evidence to distinguish bacterial CAP from atypical CAP. Depending on the causative organism, definitive therapy may range from 45 to 100 mg/kg/day PO in divided doses. In HIV-infected patients, amoxicillin is recommended as part of combination therapy for outpatients.

    For the treatment of urinary tract infection (UTI), including cystitis, and urinary tract infection (UTI) prophylaxis*:
    Oral dosage (immediate-release):
    Neonates and Infants 3 months and younger: 30 mg/kg/day PO given in divided doses every 12 hours.
    Infants 4 to 11 months, Children, and Adolescents: 20 mg/kg/day PO in divided doses every 8 hours (Max: 250 mg/dose) or 25 mg/kg/day PO in divided doses every 12 hours (Max: 500 mg/dose) for mild to moderate infections and 40 mg/kg/day PO in divided doses every 8 hours (Max: 500 mg/dose) or 45 mg/kg/day PO in divided doses every 12 hours (Max: 875 mg/dose) for severe infections.
    -for urinary tract infection (UTI) prophylaxis* in infants with hydronephrosis or vesicoureteral reflux:
    NOTE: Guidelines from the Pediatric Vesicoureteral Reflux (VUR) Panel recommend antibiotic prophylaxis for all grades of vesicoureteral reflux in all children younger than 1 year. The American Academy of Pediatrics (AAP) states that routine antimicrobial prophylaxis for patients 2 to 24 months with vesicoureteral reflux is not supported by currently available data; however, antimicrobial prophylaxis is still utilized and has biological plausibility. Further research is needed. Amoxicillin is not recommended beyond 2 months of age due to resistance concerns. Sulfamethoxazole; trimethoprim or nitrofurantoin are preferred agents for infants 2 months and older.
    Oral dosage (immediate-release):
    Neonates and Infants younger than 2 months: 10 to 15 mg/kg/dose PO once daily.

    For the treatment of Lyme disease*:
    Oral dosage (immediate-release):
    Infants, Children, and Adolescents: 50 mg/kg/day PO in divided doses every 8 hours (Max: 1.5 g/day). Treat for 14 to 21 days for early stage Lyme disease/erythema migrans, 21 days for acrodermatitis chronica atrophicans, and 28 days for Lyme arthritis.

    For bacterial endocarditis prophylaxis*:
    Oral dosage (immediate-release):
    Children and Adolescents: 50 mg/kg PO as a single dose (Max: 2 g/dose) given 30 to 60 minutes before procedure. Prophylaxis is recommended for at-risk cardiac patients undergoing dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa. Cardiac patients that are considered to be at highest risk include those with prosthetic cardiac valves or prosthetic material used for cardiac valve repair, previous infective endocarditis, select types of congenital heart disease (CHD), and cardiac transplantation with valvulopathy.

    For Helicobacter pylori (H. pylori) eradication*:
    NOTE: Eradication is recommended in children with H. pylori-positive peptic ulcer disease and may be considered in children infected with H. pylori and whose first degree relative has gastric cancer.
    -in combination with metronidazole and a proton pump inhibitor (PPI):
    Oral dosage (immediate-release):
    Children and Adolescents: 25 mg/kg/dose PO twice daily (Max: 1 g/dose) with metronidazole (10 mg/kg/dose PO twice daily [Max: 500 mg/dose]) and a proton pump inhibitor (PPI; 1 to 2 mg/kg/day PO divided every 12 hours [Max: 20 mg/dose]) for 1 to 2 weeks.
    -in combination with clarithromycin and a proton pump inhibitor (PPI):
    Oral dosage (immediate-release):
    Children and Adolescents: 25 mg/kg/dose PO twice daily (Max: 1 g/dose) with clarithromycin (10 mg/kg/dose PO twice daily [Max: 500 mg/dose]) and a proton pump inhibitor (PPI; 1 to 2 mg/kg/day PO divided every 12 hours [Max: 20 mg/dose]) for 1 to 2 weeks.
    -as part of a sequential therapy regimen:
    Oral dosage (immediate-release):
    Children and Adolescents: 25 mg/kg/dose PO twice daily (Max: 1 g/dose) with a proton pump inhibitor (PPI; 1 to 2 mg/kg/day PO divided every 12 hours [Max: 20 mg/dose]) for 5 days, followed-up by a PPI plus clarithromycin (10 mg/kg/dose PO twice daily [Max: 500 mg/dose]) and metronidazole (10 mg/kg/dose PO twice daily [Max: 500 mg/dose]) for 5 days.

    For the treatment of adolescent aggressive periodontitis* in combination with metronidazole after scaling and root planing:
    Oral dosage (immediate-release):
    Adolescents 16 to 17 years: 250 to 375 mg PO 3 times daily with metronidazole (250 mg PO 3 times daily) for 7 to 10 days.

    For the treatment of typhoid fever* due to Salmonella typhii:
    Oral dosage (immediate-release):
    Children and Adolescents: 50 to 100 mg/kg/day PO in 3 to 4 divided doses for 14 days.
    -for management of Salmonella typhii chronic carrier patients*:
    Oral dosage (immediate-release):
    Children and Adolescents: 100 mg/kg/day PO in 3 to 4 divided doses plus probenecid (23 mg/kg/day PO [Max: 1 g/day]) for 6 weeks.

    For the treatment of cutaneous anthrax* infection due to exposure to Bacillus anthracis or as oral follow-up therapy for severe anthrax:
    Oral dosage (immediate-release):
    Premature neonates 32 to 37 weeks gestational age and 7 days or younger: 50 mg/kg/day PO divided every 12 hours as an alternative for penicillin-susceptible strains. Treat for 7 to 10 days for naturally acquired infection. For a bioterrorism-related event, continue treatment for 60 days. As oral follow-up combination therapy after initial IV therapy for severe anthrax (non-CNS infection), use amoxicillin in combination with a protein synthesis inhibitor (i.e., clindamycin, linezolid). Continue therapy to complete a treatment course of at least 14 days; additional prophylaxis to complete an antimicrobial course of up to 60 days may be required.
    Premature neonates 32 to 37 weeks gestational age and older than 7 days: 75 mg/kg/day PO divided every 8 hours as an alternative for penicillin-susceptible strains. Treat for 7 to 10 days for naturally acquired infection. For a bioterrorism-related event, continue treatment for 60 days. As oral follow-up combination therapy after initial IV therapy for severe anthrax (non-CNS infection), use amoxicillin in combination with a protein synthesis inhibitor (i.e., clindamycin, linezolid). Continue therapy to complete a treatment course of at least 14 days; additional prophylaxis to complete an antimicrobial course of up to 60 days may be required.
    Neonates, Infants, Children, and Adolescents: 75 mg/kg/day PO divided every 8 hours (Max: 1 g/dose) as an alternative for penicillin-susceptible strains. Treat for 7 to 10 days for naturally acquired infection. For a bioterrorism-related event, continue treatment for 60 days. As oral follow-up combination therapy after initial IV therapy for severe anthrax (non-CNS infection), use amoxicillin in combination with a protein synthesis inhibitor (i.e., clindamycin, doxycycline, linezolid). Continue therapy to complete a treatment course of at least 14 days; additional prophylaxis to complete an antimicrobial course of up to 60 days may be required.

    For anthrax prophylaxis* after exposure to Bacillus anthracis:
    Oral dosage (immediate-release):
    Premature neonates 32 to 37 weeks gestational age and 7 days or younger: 50 mg/kg/day PO divided every 12 hours for 60 days after exposure for penicillin-susceptible strains.
    Premature neonates 32 to 37 weeks gestational age and older than 7 days: 75 mg/kg/day PO divided every 8 hours for 60 days after exposure for penicillin-susceptible strains.
    Neonates, Infants, Children, and Adolescents: 75 mg/kg/day PO divided every 8 hours (Max: 1 g/dose) for 60 days after exposure for penicillin-susceptible strains.

    Maximum Dosage Limits:
    -Neonates
    30 mg/kg/day PO is FDA-approved maximum; however, doses up to 75 mg/kg/day PO have been used off-label.
    -Infants
    1 to 3 months: 30 mg/kg/day PO is FDA-approved maximum; however, doses up to 75 mg/kg/day PO have been used off-label.
    4 to 11 months: 45 mg/kg/day PO is FDA-approved maximum; however, doses up to 90 mg/kg/day PO have been used off-label.
    -Children
    45 mg/kg/day PO is FDA-approved maximum; however, doses up to 100 mg/kg/day PO (Max: 4 g/day) have been used off-label.
    -Adolescents
    1,750 mg/day PO is FDA-approved maximum; however, doses up to 4 g/day PO have been used off-label.

    Patients with Hepatic Impairment Dosing
    No dosage adjustment needed; amoxicillin is not appreciably metabolized in the liver and does not undergo biliary secretion.

    Patients with Renal Impairment Dosing
    Data for dosage adjustments in pediatric patients with renal impairment are not available; however, dosage intervals should be adjusted.The following dosing adjustments are recommended for adults with renal impairment.
    CrCl > 30 ml/min: no dosage adjustment needed.
    CrCl 10-30 ml/min: 250-500 mg PO every 12 hours, depending on the severity of the infection. Do not use the 875 mg-tablet strength or the extended-release tablet for dosing.
    CrCl < 10 ml/min: 250-500 mg PO every 24 hours, depending on the severity of the infection. Do not use the 875 mg-tablet strength or the extended-release tablet for dosing.

    Intermittent hemodialysis
    Data in pediatric patients are not available. For adults, the usual dose (i.e. 250-500 mg depending on severity of infection) remains the same but the dosing interval is extended to every 24 hours. According to the manufacturer, an additional dose should be given both during and at the end of a dialysis session. Do not use the 875 mg tablet or the extended-release tablet for dosing.

    *non-FDA-approved indication

    Monograph content under development

    Mechanism of Action: Beta-lactam antibiotics such as amoxicillin are mainly bactericidal. Like other penicillins, amoxicillin inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. Penicillin-binding proteins are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. Penicillin-binding proteins vary among different bacterial species. Thus, the intrinsic activity of amoxicillin, as well as the other penicillins, against a particular organism depends on their ability to gain access to and bind with the necessary PBP. The aminopenicillins are able to penetrate gram-negative bacteria more readily than are the natural penicillins or penicillinase-resistant penicillins due to the presence of a free amino group within the structure. Like all beta-lactam antibiotics, amoxicillin's ability to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor. Prevention of the autolysin response to beta-lactam antibiotic exposure through loss of autolytic activity (mutation) or inactivation of autolysin (low-medium pH) by the microorganism can lead to tolerance to the beta-lactam antibiotic resulting in bacteriostatic activity.

    Pharmacokinetics: Amoxicillin is administered orally. Approximately 20% of the circulating drug is protein-bound. Amoxicillin is widely distributed into most body tissues and fluids, excluding the brain and spinal fluid except when meninges are inflamed. Amoxicillin does cross the placenta. A small percentage is excreted in breast milk. The unchanged drug and its metabolites are excreted into the urine primarily via tubular secretion and glomerular filtration. In adults , approximately 60% of an orally administered dose is excreted in the urine primarily via tubular secretion and glomerular filtration within 6-8 hours; concurrent administration of probenecid prolongs urinary excretion. In patients with normal renal function, the elimination half-life of amoxicillin is 1-1.5 hours.

    Affected cytochrome P450 isoenzymes: none


    -Route-Specific Pharmacokinetics
    Oral Route
    Amoxicillin is stable in the presence of gastric acid and is rapidly absorbed. Amoxicillin is more completely absorbed than ampicillin and, for this reason, is often the preferred oral aminopenicillin.

    Immediate-release formulations
    Peak concentrations are reached 1 to 2 hours after administration in adults.

    Extended-release formulation
    Administration of the extended-release formulation results in slower amoxicillin absorption compared to immediate-release products; peak concentrations are reached approximately 3 hours after administration. Amoxicillin exposure (AUC) achieved with the extended-release formulation is similar to that observed after oral administration of a comparable dose of immediate-release amoxicillin suspension. Food decreases the rate, but does not alter the extent of absorption.


    -Special Populations
    Pediatrics
    Neonates and Young Infants
    Because of incompletely developed renal function in neonates and young infants, the elimination of amoxicillin may be delayed. Dosing should be modified in pediatric patients 12 weeks of age or younger (3 months or age or less).

    Renal Impairment
    Pharmacokinetic data are unavailable in pediatric patients with renal impairment. However, amoxicillin is substantially eliminated by the kidneys and elimination half-life increases as renal function declines. Studies in adult patients have shown that the elimination half-life of amoxicillin is prolonged to approximately 10-13 hours in patients with end-stage renal disease. Dosage adjustments are recommended in patients with severe renal impairment.

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