Amoxicillin

7 DRUG INTERACTIONS Co-administration with probenicid is not recommended. ( 7.1 ) Concomitant use of amoxicillin and oral anticoagulants may increase the prolongation of prothrombin time. ( 7.2 ) Co-administration with allopurinol increases the risk of rash. ( 7.3 ) Amoxicillin may reduce the efficacy of oral contraceptives. ( 7.4 ) 7.1 Probenecid Probenecid decreases the renal tubular secretion of amoxicillin. Concurrent use of amoxicillin and probenecid may result in increased and prolonged blood levels of amoxicillin. 7.2 Oral Anticoagulants Abnormal prolongation of prothrombin time (increased international normalized ratio [INR]) has been reported in patients receiving amoxicillin and oral anticoagulants. Appropriate monitoring should be undertaken when anticoagulants are prescribed concurrently. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation. 7.3 Allopurinol The concurrent administration of allopurinol and amoxicillin increases the incidence of rashes in patients receiving both drugs as compared to patients receiving amoxicillin alone. It is not known whether this potentiation of rashes is due to allopurinol or the hyperuricemia present in these patients. 7.4 Oral Contraceptives Amoxicillin may affect the intestinal flora, leading to lower estrogen reabsorption and reduced efficacy of combined oral estrogen/progesterone contraceptives. 7.5 Other Antibacterials Chloramphenicol, macrolides, sulfonamides, and tetracyclines may interfere with the bactericidal effects of penicillin. This has been demonstrated in vitro ; however, the clinical significance of this interaction is not well documented. 7.6 Effects on Laboratory Tests High urine concentrations of ampicillin may result in false-positive reactions when testing for the presence of glucose in urine using CLINITEST ® , Benedict’s Solution, or Fehling’s Solution. Since this effect may also occur with amoxicillin, it is recommended that glucose tests based on enzymatic glucose oxidase reactions (such as CLINISTIX ® ) be used. Following administration of ampicillin or amoxicillin to pregnant women, a transient decrease in plasma concentration of total conjugated estriol, estriol-glucuronide, conjugated estrone, and estradiol has been noted.

Amoxicillin treats infections caused by susceptible bacteria, including ear/nose/throat infections, genitourinary tract infections, skin infections, lower respiratory tract infections, and acute uncomplicated gonorrhea. It's also indicated for H. pylori eradication to reduce duodenal ulcer recurrence risk when combined with other medications.

2 DOSAGE AND ADMINISTRATION In Adults, 750 to 1750 mg/day in divided doses every 8 to 12 hours. In Pediatric Patients over 3 Months of Age, 20 to 45 mg/kg/day in divided doses every 8 to 12 hours. Refer to full prescribing information for specific dosing regimens. ( 2.2 , 2.3 ) The upper dose for neonates and infants aged 3 months or younger is 30 mg/kg/day divided every 12 hours. ( 2.3 ) Dosing for H. pylori Infection (in Adults): Triple therapy: 1 gram amoxicillin, 500 mg clarithromycin, and 30 mg lansoprazole, all given twice daily (every 12 hours) for 14 days. Dual therapy: 1 gram amoxicillin and 30 mg lansoprazole, each given three times daily (every 8 hours) for 14 days. ( 2.4 ) Reduce the dose in patients with severe renal impairment (GFR greater than 30 mL/min). ( 2.5 ) 2.1 Important Administration Instructions To minimize the potential for gastrointestinal intolerance, amoxicillin for oral suspension should be taken at the start of a meal. 2.2 Dosage for Adults and Pediatric Patients Aged 3 Months (12 weeks) and Older Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic, or evidence of bacterial eradication has been obtained. It is recommended that there be at least 10 days’ treatment for any infection caused by Streptococcus pyogenes to prevent the occurrence of acute rheumatic fever. In some infections, therapy may be required for several weeks. It may be necessary to continue clinical and/or bacteriological follow-up for several months after cessation of therapy. Table 1. Dosage Recommendations for Adult and Pediatric Patients Aged 3 Months (12 weeks) and Older Infection Severity a Recommended Dosage for Adults and Pediatric Patients Aged 3 Months and Older and Weight Greater than 40 kg Recommended Dosage for Pediatric Patients Aged 3 Months and Older and Weight Less than 40 kg Ear/Nose/Throat Skin/Skin Structure Genitourinary Tract Mild/Moderate 500 mg every 12 hours or 250 mg every 8 hours 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours Severe 875 mg every 12 hours or 500 mg every 8 hours 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours Lower Respiratory Tract Mild/Moderate or Severe 875 mg every 12 hours or 500 mg every 8 hours 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours a Dosage for infections caused by bacteria that are intermediate in their susceptibility to amoxicillin should follow the recommendations for severe infections. 2.3 Dosage in Pediatric Patients Aged Less than 12 Weeks (3 months) It is recommended that there be at least 10 days’ treatment for any infection caused by Streptococcus pyogenes to prevent the occurrence of acute rheumatic fever. Due to incompletely developed renal function affecting elimination of amoxicillin in this age group, the recommended upper dose of amoxicillin for oral suspension is 30 mg/kg/day divided every 12 hours. There are currently no dosing recommendations for pediatric patients with impaired renal function. Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic, or evidence of bacterial eradication has been obtained. 2.4 Dosage for H. pylori Infection in Adults Triple therapy: The recommended adult oral dose is 1 gram amoxicillin, 500 mg clarithromycin, and 30 mg lansoprazole, all given twice daily (every 12 hours) for 14 days. Dual therapy: The recommended adult oral dose is 1 gram amoxicillin and 30 mg lansoprazole, each given three times daily (every 8 hours) for 14 days. Please refer to clarithromycin and lansoprazole full prescribing information. 2.5 Dosage in Renal Impairment for Adults and Pediatric Patients Aged 3 Months and Older and Weight Greater than 40 kg Patients with impaired renal function do not generally require a reduction in dose unless the impairment is severe. Renal impairment patients with a glomerular filtration rate of less than 30 mL/min should NOT receive the 875 mg dose. See dosage regimens in patients with severe renal impairment provided in Table 2. Table 2. Dosing in Patients with Severe Renal Impairment Patients with Renal Impairment Dosage Regimen GFR 10 to 30 mL/min 500 mg or 250 mg every 12 hours, depending on the severity of the infection GFR less than 10 mL/min 500 mg or 250 mg every 24 hours, depending on severity of the infection Hemodialysis 500 mg or 250 mg every 24 hours, depending on severity of the infection Administer an additional dose both during and at the end of dialysis 2.6 Directions for Mixing Oral Suspension Prepare a suspension at time of dispensing as follows: Tap bottle until all powder flows freely. Measure the total amount of water (see Table 3). Add approximately 1/3 of the water to powder. Replace cap and shake vigorously to wet powder. Add remaining water. Replace cap and shake vigorously . Table 3. Amount of Water for Mixing For Oral Suspension Strength Bottle Size Total Amount of Water Required for Reconstitution For Oral Suspension 125 mg/5 mL 80 mL 58 mL 100 mL 72 mL 150 mL 106 mL For Oral Suspension 250 mg/5 mL 80 mL 58 mL 100 mL 72 mL 150 mL 106 mL After reconstitution, the required amount of suspension should be placed directly on the child’s tongue for swallowing. Alternate means of administration are to add the required amount of suspension to formula, milk, fruit juice, water, ginger ale, or cold drinks. These preparations should then be taken immediately. SHAKE ORAL SUSPENSION WELL BEFORE USING. Keep bottle tightly closed. Any unused portion of the reconstituted suspension must be discarded after 14 days. Refrigeration is preferable, but not required.

Gastrointestinal: Nausea, vomiting, diarrhea, pseudomembranous colitis Hypersensitivity: Rashes, Stevens-Johnson syndrome, exfoliative dermatitis Other: Elevated liver enzymes, crystalluria, anemia, thrombocytopenia, tooth discoloration (rare, primarily pediatric) For H. pylori triple therapy: diarrhea (7%), headache (6%), taste disturbance (5%)