Amoxil

Mechanism Of Action

Amoxicillin is an antibacterial drug. [see Microbiology].

Pharmacokinetics

Amoxicillin is stable in the presence of gastric acid and is rapidly absorbed after oral administration. The effect of food on the absorption of amoxicillin from the tablets and suspension of AMOXIL has been partially investigated; 400-mg and 875-mg formulations have been studied only when administered at the start of a light meal.

Orally administered doses of 250-mg and 500-mg amoxicillin capsules result in average peak blood levels 1 to 2 hours after administration in the range of 3.5 mcg/mL to 5.0 mcg/mL and 5.5 mcg/mL to 7.5 mcg/mL, respectively.

Mean amoxicillin pharmacokinetic parameters from an open, two-part, single-dose crossover bioequivalence study in 27 adults comparing 875 mg of AMOXIL with 875 mg of AUGMENTIN® (amoxicillin/clavulanate potassium) showed that the 875-mg tablet of AMOXIL produces an AUC0-∞ of 35.4 ± 8.1 mcg•hr/mL and a Cmax of 13.8 ± 4.1 mcg/mL. Dosing was at the start of a light meal following an overnight fast.

Orally administered doses of amoxicillin suspension, 125 mg/5 mL and 250 mg/5 mL, result in average peak blood levels 1 to 2 hours after administration in the range of 1.5 mcg/mL to 3.0 mcg/mL and 3.5 mcg/mL to 5.0 mcg/mL, respectively.

Oral administration of single doses of 400-mg chewable tablets and 400 mg/5 mL suspension of AMOXIL to 24 adult volunteers yielded comparable pharmacokinetic data:

Table 3: Mean Pharmacokinetic Parameters of Amoxicillin (400 mg chewable tablets and 400 mg/5 mL suspension) in Healthy Adults

Amoxicillin diffuses readily into most body tissues and fluids, with the exception of brain and spinal fluid, except when meninges are inflamed. In blood serum, amoxicillin is approximately 20% protein-bound. Following a 1-gram dose and utilizing a special skin window technique to determine levels of the antibiotic, it was noted that therapeutic levels were found in the interstitial fluid.

The half-life of amoxicillin is 61.3 minutes. Approximately 60% of an orally administered dose of amoxicillin is excreted in the urine within 6 to 8 hours. Detectable serum levels are observed up to 8 hours after an orally administered dose of amoxicillin. Since most of the amoxicillin is excreted unchanged in the urine, its excretion can be delayed by concurrent administration of probenecid [see DRUG INTERACTIONS].

Microbiology

Amoxicillin is similar to penicillin in its bactericidal action against susceptible bacteria during the stage of active multiplication. It acts through the inhibition of cell wall biosynthesis that leads to the death of the bacteria.

Resistance to amoxicillin is mediated primarily through enzymes called beta-lactamases that cleave the beta-lactam ring of amoxicillin, rendering it inactive.

Amoxicillin has been shown to be active against most isolates of the bacteria listed below, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Enterococcus faecalis
Staphylococcus spp.
Streptococcus pneumoniae
Streptococcus spp. (alpha and beta-hemolytic)

Escherichia coli
Haemophilus influenzae
Helicobacter pylori
Proteus mirabilis

When available, the clinical microbiology laboratory should provide cumulative in vitro susceptibility test results for antimicrobial drugs used in local hospitals and practice areas to the physician as periodic reports that describe the susceptibility profile of nosocomial and community-acquired pathogens. These reports should aid the physician in selecting the most effective antimicrobial.

Dilution Techniques: Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized test method -(broth or agar)2,4. The MIC values should be interpreted according to the criteria in Table 4.

Diffusion Techniques: Quantitative methods that require measurement of zone diameters can also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds3,4. The zone size should be determined using a standardized test method3.

Susceptibility to amoxicillin of Enterococcus spp., Enterobacteriaceae, and H. influenzae, may be inferred by testing ampicillin4. Susceptibility to amoxicillin of Staphylococcus spp., and beta-hemolytic Streptococcus spp., may be inferred by testing penicillin4. The majority of isolates of Enterococcus spp. that are resistant to ampicillin or amoxicillin produce a TEM-type beta-lactamase. A beta-lactamase test can provide a rapid means of determining resistance to ampicillin and amoxicillin4.

Susceptibility to amoxicillin of Streptococcus pneumoniae (non-meningitis isolates) may be inferred by testing penicillin or oxacillin4. The interpretive criteria for S. pneumoniae to amoxicillin are provided in Table 44.

Table 4: Susceptibility Interpretive Criteria for Amoxicillin

A report of “Susceptible” indicates the antimicrobial is likely to inhibit growth of the pathogen if the antimicrobial  compound reaches a concentration at the infection site necessary to inhibit growth of the pathogen. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated. This category also provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates the antimicrobial is not likely to inhibit growth of the pathogen if the antimicrobial compound reaches the concentration usually achievable at the infection site; other therapy should be selected.

Amoxicillin in vitro susceptibility testing methods for determining minimum inhibitory concentrations (MICs) and zone sizes have not been standardized, validated, or approved for testing H. pylori. Specimens for H. pylori and clarithromycin susceptibility test results should be obtained on isolates from patients who fail triple therapy. If clarithromycin resistance is found, a non-clarithromycin-containing regimen should be used.

Quality Control

Standardized susceptibility test procedures2,3,4 require use of laboratory controls to monitor and ensure the accuracy and precision of the supplies and reagents used in the assay, and the techniques of the individuals performing the test control. Standard amoxicillin powder should provide the following range of MIC values provided in Table 54. For the diffusion technique the criteria provided in Table 5 should be achieved.

Table 5: Acceptable Quality Control Ranges for Amoxicillina

Clinical Studies

H. pylori Eradication To Reduce The Risk Of Duodenal Ulcer Recurrence

Randomized, double-blind clinical studies performed in the United States in patients with H. pylori and duodenal ulcer disease (defined as an active ulcer or history of an ulcer within 1 year) evaluated the efficacy of lansoprazole in combination with amoxicillin capsules and clarithromycin tablets as triple 14-day therapy, or in combination with amoxicillin capsules as dual 14-day therapy, for the eradication of H. pylori. Based on the results of these studies, the safety and efficacy of 2 different eradication regimens were established: Triple therapy: Amoxicillin 1 gram twice daily/clarithromycin 500 mg twice daily/lansoprazole 30 mg twice daily (see Table 6). Dual therapy: Amoxicillin 1 gram three times daily/lansoprazole 30 mg three times daily (see Table 7. All treatments were for 14 days. H. pylori eradication was defined as 2 negative tests (culture and histology) at 4 to 6 weeks following the end of treatment. Triple therapy was shown to be more effective than all possible dual therapy combinations. Dual therapy was shown to be more effective than both monotherapies. Eradication of H. pylori has been shown to reduce the risk of duodenal ulcer recurrence.

Table 6: H. pylori Eradication Rates When Amoxicillin is Administered as Part of a Triple Therapy Regimen

Table 7: H. pylori Eradication Rates When Amoxicillin is Administered as Part of a Dual Therapy Regimen

REFERENCES

1. Swanson-Biearman B, Dean BS, Lopez G, Krenzelok EP. The effects of penicillin and cephalosporin ingestions in children less than six years of age. Vet Hum Toxicol. 1988; 30: 66-67.

2. Clinical and Laboratory Standards Institute (CLSI). Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically; Approved Standard – Tenth Edition. CLSI document M07-A10, Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2015.

3. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Disk Diffusion Susceptibility Tests; Approved Standard – Twelfth Edition. CLSI document M02-A12, Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2015.

4. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing; Twenty-fifth Informational Supplement, CLSI document M100-S25. CLSI document M100-S25, Clinical and Laboratory Standards Institute, 950 West Valley Road, Suite 2500, Wayne, Pennsylvania 19087, USA, 2015.

Amoxil is a prescription medication used to treat certain bacterial infections such as pneumonia, bronchitis, gonorrhea, and certain types of ulcers.  It can also treat bacterial infections of the ears, nose, throat, urinary tract, and skin.  This medication belongs to a group of drugs called penicillin antibiotics, which work by blocking the growth of bacteria.

Amoxil comes as a capsule, tablet, chewable tablet, and oral suspension (liquid) forms. This medication is taken up to 3 times daily, with or without food.

Common side of Amoxil effects include nausea, vomiting, diarrhea, and headache.

Serious side effects have been reported with Amoxicillin. See the “Drug Precautions” section.

Common side effects of amoxicillin include the following:

• nausea
• vomiting
• diarrhea
• headache

This is not a complete list of amoxicillin side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

• Keep this and all medications out of the reach of children.
• Store amoxicillin capsules, tablets, and chewable tablets in the original container, tightly closed, away from excess heat (at room temperature) and moisture.
• The liquid suspension and pediatric drops are best kept in the refrigerator, but may be stored at room temperature. Do not freeze. Throw away any unused liquid amoxicillin after 14 days.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Stop taking this medicine and get emergency help immediately if any of the following effects occur:

• Fast or irregular breathing
• fever
• joint pain
• lightheadedness or fainting (sudden)
• puffiness or swelling around the face
• red, scaly skin
• shortness of breath
• skin rash, hives, itching

Check with your doctor immediately if any of the following side effects occur:

• Abdominal or stomach cramps and pain (severe)
• abdominal tenderness
• convulsions (seizures)
• decreased amount of urine
• diarrhea (watery and severe), which may also be bloody
• mental depression
• nausea and vomiting
• pain at place of injection
• sore throat and fever
• unusual bleeding or bruising
• yellow eyes or skin

• Agitation or combativeness
• anxiety
• confusion
• fear of impending death
• feeling, hearing, or seeing things that are not real

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Diarrhea (mild)
• headache
• sore mouth or tongue
• vaginal itching and discharge
• white patches in the mouth and/or on the tongue

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Amoxicillin is stable in the presence of gastric acid and is rapidly absorbed after oral administration. The effect of food on the absorption of amoxicillin from the tablets and suspension of Amoxil has been partially investigated. The 400-mg and 875-mg formulations have been studied only when administered at the start of a light meal. However, food effect studies have not been performed with the 200-mg and 500-mg formulations. Amoxicillin diffuses readily into most body tissues and fluids, with the exception of brain and spinal fluid, except when meninges are inflamed. The half-life of amoxicillin is 61.3 minutes. Most of the amoxicillin is excreted unchanged in the urine; its excretion can be delayed by concurrent administration of probenecid. In blood serum, amoxicillin is approximately 20% protein-bound.

Orally administered doses of 250-mg and 500-mg amoxicillin capsules result in average peak blood levels 1 to 2 hours after administration in the range of 3.5 mcg/mL to 5.0 mcg/mL and 5.5 mcg/mL to 7.5 mcg/mL, respectively.

Mean amoxicillin pharmacokinetic parameters from an open, two-part, single-dose crossover bioequivalence study in 27 adults comparing 875 mg of Amoxil with 875 mg of AUGMENTIN® (amoxicillin/clavulanate potassium) showed that the 875-mg tablet of Amoxil produces an AUC0-∞ of 35.4 ± 8.1 mcg•hr/mL and a Cmax of 13.8 ± 4.1 mcg/mL. Dosing was at the start of a light meal following an overnight fast.

Orally administered doses of amoxicillin suspension, 125 mg/5 mL and 250 mg/5 mL, result in average peak blood levels 1 to 2 hours after administration in the range of 1.5 mcg/mL to 3.0 mcg/mL and 3.5 mcg/mL to 5.0 mcg/mL, respectively.

Oral administration of single doses of 400-mg chewable tablets and 400 mg/5 mL suspension of Amoxil to 24 adult volunteers yielded comparable pharmacokinetic data:

a  Administered at the start of a light meal.

b  Mean values of 24 normal volunteers. Peak concentrations occurred approximately 1 hour after the dose.

Detectable serum levels are observed up to 8 hours after an orally administered dose of amoxicillin. Following a 1-gram dose and utilizing a special skin window technique to determine levels of the antibiotic, it was noted that therapeutic levels were found in the interstitial fluid. Approximately 60% of an orally administered dose of amoxicillin is excreted in the urine within 6 to 8 hours.

Microbiology

Amoxicillin is similar to ampicillin in its bactericidal action against susceptible organisms during the stage of active multiplication. It acts through the inhibition of biosynthesis of cell wall mucopeptide. Amoxicillin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Enterococcus faecalis

Staphylococcus spp.* (β-lactamase–negative strains only)

Streptococcus pneumoniae

Streptococcus spp. (α- and β-hemolytic strains only)

*Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.

Escherichia coli (β-lactamase–negative strains only)

Haemophilus influenzae (β-lactamase–negative strains only)

Neisseria gonorrhoeae (β-lactamase–negative strains only)

Proteus mirabilis (β-lactamase–negative strains only)

Helicobacter pylori

Susceptibility Tests

Quantitative methods are used to determine antimicrobial minimum inhibitory concentrations (MICs). These MICs provide estimates of the susceptibility of bacteria to antimicrobial compounds. The MICs should be determined using a standardized procedure. Standardized procedures are based on a dilution method1 (broth or agar) or equivalent with standardized inoculum concentrations and standardized concentrations of ampicillin powder. Ampicillin is sometimes used to predict susceptibility of S. pneumoniae to amoxicillin; however, some intermediate strains have been shown to be susceptible to amoxicillin. Therefore, S. pneumoniae susceptibility should be tested using amoxicillin powder. The MIC values should be interpreted according to the following criteria:

For Gram-Positive Aerobes:

Enterococcus

Staphylococcusa

Streptococcus (except S. pneumoniae)

S. pneumoniaeb from non-meningitis sources.

(Amoxicillin powder should be used to determine susceptibility.)

NOTE: These interpretive criteria are based on the recommended doses for respiratory tract infections.

For Gram-Negative Aerobes:

Enterobacteriaceae

H. influenzaec

a Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.

b These interpretive standards are applicable only to broth microdilution susceptibility tests using cation-adjusted Mueller-Hinton broth with 2-5% lysed horse blood.

c These interpretive standards are applicable only to broth microdilution test with H. influenzae using Haemophilus Test Medium (HTM).1

A report of “Susceptible” indicates that the pathogen is likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable. A report of “Intermediate” indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible drugs, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high dosage of drug can be used. This category also provides a buffer zone, which prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of “Resistant” indicates that the pathogen is not likely to be inhibited if the antimicrobial compound in the blood reaches the concentrations usually achievable; other therapy should be selected.

Standardized susceptibility test procedures require the use of laboratory control microorganisms to control the technical aspects of the laboratory procedures. Standard ampicillin powder should provide the following MIC values:

Using amoxicillin to determine susceptibility:

d  This quality control range is applicable to only H. influenzae ATCC 49247 tested by a broth microdilution procedure using HTM.1

e  This quality control range is applicable to only S. pneumoniae ATCC 49619 tested by the broth microdilution procedure using cation-adjusted Mueller-Hinton broth with 2-5% lysed horse blood.

Quantitative methods that require measurement of zone diameters also provide reproducible estimates of the susceptibility of bacteria to antimicrobial compounds. One such standardized procedure2 requires the use of standardized inoculum concentrations. This procedure uses paper disks impregnated with 10 mcg ampicillin to test the susceptibility of microorganisms, except S. pneumoniae, to amoxicillin. Interpretation involves correlation of the diameter obtained in the disk test with the MIC for ampicillin.

Reports from the laboratory providing results of the standard single-disk susceptibility test with a 10-mcg ampicillin disk should be interpreted according to the following criteria:

For Gram-Positive Aerobes:

Enterococcus

Staphylococcusf

β-hemolytic streptococci

NOTE: For streptococci (other than β-hemolytic streptococci and S. pneumoniae), an ampicillin MIC should be determined.

S. pneumoniae

S. pneumoniae should be tested using a 1-mcg oxacillin disk. Isolates with oxacillin zone sizes of ≥ 20 mm are susceptible to amoxicillin. An amoxicillin MIC should be determined on isolates of S. pneumoniae with oxacillin zone sizes of ≤ 19 mm.

For Gram-Negative Aerobes:

Enterobacteriaceae

H. influenzaeg

f  Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.

g  These interpretive standards are applicable only to disk diffusion susceptibility tests with H. influenzae using Haemophilus Test Medium (HTM).2

Interpretation should be as stated above for results using dilution techniques.

As with standard dilution techniques, disk diffusion susceptibility test procedures require the use of laboratory control microorganisms. The 10-mcg ampicillin disk should provide the following zone diameters in these laboratory test quality control strains:

Using 1-mcg oxacillin disk:

h  This quality control range is applicable to only H. influenzae ATCC 49247 tested by a disk diffusion procedure using HTM.2

i  This quality control range is applicable to only S. pneumoniae ATCC 49619 tested by a disk diffusion procedure using Mueller-Hinton agar supplemented with 5% sheep blood and incubated in 5% CO2.

Susceptibility Testing for Helicobacter pylori

In vitro susceptibility testing methods and diagnostic products currently available for determining minimum inhibitory concentrations (MICs) and zone sizes have not been standardized, validated, or approved for testing H. pylori microorganisms.

Culture and susceptibility testing should be obtained in patients who fail triple therapy. If clarithromycin resistance is found, a non-clarithromycin-containing regimen should be used.

Amoxil is indicated in the treatment of infections due to susceptible (ONLY β-lactamase–negative) strains of the designated microorganisms in the conditions listed below:

Infections of the ear, nose, and throat – due to Streptococcus spp. (α- and β-hemolytic strains only), S. pneumoniae, Staphylococcus spp., or H. influenzae.

Infections of the genitourinary tract – due to E. coli, P. mirabilis, or E. faecalis.

Infections of the skin and skin structure – due to Streptococcus spp. (α- and β-hemolytic strains only), Staphylococcus spp., or E. coli.

Infections of the lower respiratory tract – due to Streptococcus spp. (α- and β-hemolytic strains only), S. pneumoniae,Staphylococcus spp., or H. influenzae.

Gonorrhea, acute uncomplicated (ano-genital and urethral infections) – due to N. gonorrhoeae (males and females).

H. pylori eradication to reduce the risk of duodenal ulcer recurrence

Triple Therapy

Amoxil/clarithromycin/lansoprazole

Amoxil, in combination with clarithromycin plus lansoprazole as triple therapy, is indicated for the treatment of patients with H. pylori infection and duodenal ulcer disease (active or 1-year history of a duodenal ulcer) to eradicate H. pylori. Eradication of H. pylori has been shown to reduce the risk of duodenal ulcer recurrence. (See CLINICAL STUDIES and DOSAGE AND ADMINISTRATION.)

Dual Therapy

Amoxil/lansoprazole

Amoxil, in combination with lansoprazole delayed-release capsules as dual therapy, is indicated for the treatment of patients with H. pylori infection and duodenal ulcer disease (active or 1-year history of a duodenal ulcer) who are either allergic or intolerant to clarithromycin or in whom resistance to clarithromycin is known or suspected. (See the clarithromycin package insert, MICROBIOLOGY.) Eradication of H. pylori has been shown to reduce the risk of duodenal ulcer recurrence. (See CLINICAL STUDIES and DOSAGE AND ADMINISTRATION.)

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Amoxil and other antibacterial drugs, Amoxil 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.

Indicated surgical procedures should be performed.

Take penicillin V exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

You may take penicillin V with or without food.

To be sure penicillin V is helping your condition, your blood will need to be tested on a regular basis. Your kidney or liver function may also need to be tested. Do not miss any scheduled visits to your doctor.

Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with a marked measuring spoon or medicine cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Take penicillin V for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Penicillin V will not treat a viral infection such as the common cold or flu. Do not give this medicine to another person, even if they have the same symptoms you do.

Penicillin V can cause you to have unusual results with certain medical tests. Tell any doctor who treats you that you are using penicillin V.

Store penicillin V tablets at room temperature away from moisture, heat, and light. Store liquid penicillin V in a refrigerator but do not allow it to freeze. Throw away any liquid that has not been used within 14 days after it was mixed at the pharmacy.

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include confusion, behavior changes, a severe skin rash, urinating less than usual, or seizure (black-out or convulsions).

12 years or older:
-Streptococcal infections: 125 to 250 mg orally every 6 to 8 hours for 10 days
-Pneumococcal infections: 250 to 500 mg orally every 6 hours until patient afebrile for at least 2 days

Uses:
-Streptococcal infections: For the treatment of mild to moderate infections of the upper respiratory tract
-Pneumococcal infections: For the treatment of mild to moderately severe infections of the respiratory tract, including otitis media

12 years or older: 125 to 250 mg orally twice a day

Comments:
-Prophylaxis with oral penicillin on a continuing basis has been effective in preventing recurrence.
-Since relatively penicillin-resistant alpha-hemolytic streptococci may be found in patients using continuous therapy for secondary prevention of rheumatic fever, other agents may be selected to add to their continuous prophylactic regimen.

Use: For the prevention of recurrence after rheumatic fever and/or chorea

AHA and AAP Recommendations for Children: 250 mg orally twice a day

Duration of secondary prophylaxis (after last attack):
-Rheumatic fever with carditis and residual heart disease (persistent valvular disease): 10 years or until 40 years of age (whichever is longer); sometimes lifelong prophylaxis
-Rheumatic fever with carditis and no residual heart disease (no valvular disease): 10 years or until 21 years of age (whichever is longer)
-Rheumatic fever without carditis: 5 years or until 21 years of age (whichever is longer)

Comments:
-Recommended as secondary prevention of rheumatic fever (prevention of recurrence); continuous prophylaxis provides the most effective protection.
-For high-risk patients, penicillin G benzathine every 3 weeks may be more effective and is recommended; oral therapy can be used for prevention in lower risk patients whose compliance can be ensured.
-Current guidelines should be consulted for additional information.

AHA Recommendations:
-Children 27 kg or less: 250 mg orally 2 to 3 times a day
-Children greater than 27 kg and adolescents: 500 mg orally 2 to 3 times a day
Duration of therapy: 10 days

Comments:
-Recommended for the treatment of streptococcal tonsillopharyngitis (primary prevention of rheumatic fever)
-Current guidelines should be consulted for additional information.

IDSA Recommendations:
Patients with group A streptococcal pharyngitis:
-Children: 250 mg orally 2 to 3 times a day
-Adolescents: 250 mg orally 4 times a day or 500 mg orally twice a day
Duration of therapy: 10 days

Chronic pharyngeal carriers of group A streptococci: 12.5 mg/kg orally 4 times a day for 10 days
-Maximum dose: 2 g/day

Comments:
-Recommended oral regimen for group A streptococcal pharyngitis in patients without penicillin allergy
-With 4 days of oral rifampin, recommended oral regimen for chronic carriers of group A streptococci
-Current guidelines should be consulted for additional information.

Data not available

Animal studies have failed to reveal evidence of fetal harm. This drug crosses the placenta. No positive evidence of adverse effects on the fetus observed during human use of penicillins; however, there are no controlled data in human pregnancy. AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed. US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

This drug should be used during pregnancy only if clearly needed; it has been used without apparent harmful effects. Caution is recommended. AU TGA pregnancy category: A US FDA pregnancy category: B