Augmentin

Action

Amoxicillin inhibits transpeptidase, preventing cross-linking of bacterial cell wall and leading to cell death. Addition of clavulanate (a beta-lactam) increases drug's resistance to beta-lactamase (an enzyme produced by bacteria that may inactivate amoxicillin).

Availability

Oral suspension: 125 mg amoxicillin with 31.25 mg clavulanic acid/5 ml, 200 mg amoxicillin with 28.5 mg clavulanic acid/5 ml, 250 mg amoxicillin with 62.5 mg clavulanic acid/5 ml, 400 mg amoxicillin with 57 mg clavulanic acid/5 ml, 600 mg amoxicillin with 42.9 mg clavulanic acid/5 ml

Tablets (chewable): 200 mg amoxicillin with 28.5 mg clavulanate, 400 mg amoxicillin with 57 mg clavulanate

Tablets (extended-release): 1,000 mg amoxicillin with 62.5 mg clavulanate

Tablets (film-coated): 250 mg amoxicillin with 125 mg clavulanate, 500 mg amoxicillin with 125 mg clavulanate, 875 mg amoxicillin with 125 mg clavulanate

Indications and dosages

➣ Lower respiratory tract infections, otitis media, sinusitis, skin and skin-structure infections, and urinary tract infections (UTIs) caused by susceptible strains of gram-negative and gram-positive organisms

Adults and children weighing more than 40 kg (88 lb): 500 mg q 12 hours or 250 mg P.O. q 8 hours (based on amoxicillin component). For severe infections, 875 mg P.O. q 12 hours or 500 mg P.O. q 8 hours.

➣ Serious infections and community-acquired pneumonia

Adults and children weighing more than 40 kg (88 lb): 875 mg P.O. q 12 hours or 500 mg P.O. q 8 hours

Infants and children ages 3 months and older weighing less than 40 kg (88 lb): 20 to 45 mg/kg/day P.O. in divided doses q 12 hours or 20 or 25 to 40 mg/kg/day in divided doses q 8 hours, based on severity of infection and amoxicillin component (125 mg/5 ml or 250 mg/5 ml suspension)

Infants younger than 3 months: 30 mg/kg/day P.O. (based on amoxicillin component) divided q 12 hours. (125 mg/5 ml oral suspension is recommended.)

➣ Recurrent or persistent acute otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis in children ages 2 and younger and in children who have received antibiotic therapy within last 3 months

Children ages 3 months to 12 years: 90 mg/kg/day of Augmentin ES-600 P.O. q 12 hours for 10 days

Dosage adjustment

• Severe renal impairment

• Hemodialysis

• Infants ages 3 months and younger

Contraindications

• Hypersensitivity to drug or any penicillin

• Phenylketonuria (some products)

• History of cholestatic jaundice or hepatic dysfunction associated with this drug

Precautions

Use cautiously in:

• severe renal insufficiency, infectious mononucleosis

• pregnant patients.

Administration

☞ Ask about history of penicillin allergy before giving.

• Give with or without food.

• Know that maximum dosage for infants ages 3 months and younger is 30 mg/kg/day divided q 12 hours.

• Be aware that 12-hour dosing is recommended to reduce diarrhea.

Adverse reactions

CNS: lethargy, hallucinations, anxiety, confusion, agitation, depression, dizziness, fatigue, hyperactivity, insomnia, behavioral changes, seizures (with high doses)

GI: nausea, vomiting, diarrhea, abdominal pain, stomatitis, glossitis, gastritis, black "hairy" tongue, furry tongue, enterocolitis, pseudomembranous colitis

GU: vaginitis, nephropathy, interstitial nephritis

Hematologic: anemia, thrombocytopenia, thrombocytopenic purpura, leukopenia, hemolytic anemia, agranulocytosis, bone narrow depression, eosinophilia

Hepatic: cholestatic hepatitis

Respiratory: wheezing

Skin: rash

Other: superinfections (oral and rectal candidiasis), fever, anaphylaxis

Interactions

Drug-drug. Any food: enhanced clavulanate absorption

Chloramphenicol, macrolides, sulfonamides, tetracycline: decreased amoxicillin efficacy

Hormonal contraceptives: decreased contraceptive efficacy

Probenecid: decreased renal excretion and increased blood level of amoxicillin

Drug-food. Any food: enhanced clavulanate absorption

Drug-herbs. Khat: decreased antimicrobial effect

Patient monitoring

• Monitor patient carefully for signs and symptoms of hypersensitivity reaction.

☞ Monitor for seizures when giving high doses.

• Check patient's temperature and watch for other signs and symptoms of superinfection, especially oral or rectal candidiasis.

Patient teaching

☞ Instruct patient to immediately report signs or symptoms of hypersensitivity reaction, such as rash, fever, or chills.

• Tell patient he may take drug with or without food.

• Inform patient that drug lowers resistance to some types of infections. Instruct him to report new signs or symptoms of infection (especially of mouth or rectum).

• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.

• Tell patient taking hormonal contraceptives that drug may reduce contraceptive efficacy. Suggest she use alternative birth control method.

• Inform parents that they may give liquid form of drug directly to child or may mix it with foods or beverages.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, foods, and herbs mentioned above.