AMOXICILLIN AND CLAVULANATE POTASSIUM
(a-mox-i-sill'in)
Augmentin, Augmentin-ES600, Augmentin XR, Clavulin 
Classifications: antiinfective; beta-lactam antibiotic; aminopenicillin
Prototype: Ampicillin
Pregnancy Category: B

Availability

250 mg, 500 mg, 875 mg tablets; 125 mg, 200 mg, 400 mg chewable tablets; 125 mg/5 mL, 200 mg/5 mL, 250 mg/5 mL, 400 mg/5 mL, 600 mg/5 mL oral suspension; 1000 mg amoxicillin/62.5 mg clavulanate sustained-release tablets

Actions

Used alone, clavulanic acid antibacterial activity is weak. In combination, it inhibits enzyme (beta-lactamase) degradation of amoxicillin and by synergism extends both spectrum of activity and bactericidal effect of amoxicillin against many strains of beta-lactamase-producing bacteria resistant to amoxicillin alone.

Therapeutic Effects

Semisynthetic broad-spectrum antibiotic with fixed combination of amoxicillin, an aminopenicillin, and the potassium salt to clavulanic acid, a competitive beta-lactamase inhibitor. Active against gram-positive bacteria including Staphylococcus aureus, Streptococcus pneumoniae, Clostridium, Peptococcus, Bacteroides fragilis group, and many gram-negative organisms including Branhamella catarrhalis (formerly Neisseria catarrhalis), Haemophilus influenzae, Proteus mirabilis; Salmonella, Shigella, and Klebsiella sp. Generally inactive against Pseudomonas.

Uses

Infections caused by susceptible beta-lactamase-producing organisms: lower respiratory tract infections, acute bacterial sinusitis, community acquired pneumonia, otitis media, sinusitis, skin and skin structure infections, and UTI.

Contraindications

Combination shares toxic potential of ampicillin. Hypersensitivity to penicillins; infectious mononucleosis.

Cautious Use

Pregnancy (category B), lactation.

Route & Dosage

Mild to Moderate Infections
Adult: PO 250 or 500 mg tablet (each with 125 mg clavulanic acid) q8–12h; Sustained-release tabs: 2 tablets (2000 mg amoxicillin/125 mg clavulanate) q12h x 7–10 d
Child: PO <40 kg, 20–40 mg/kg/d (based on amoxicillin component) divided q8–12h; >3 mo, 90 mg/kg/d of 600 ES divided q12h x 10 d
Neonate/Infant: PO <3 mo, 30 mg/kg/d (amoxicillin) divided q12h

Administration

Oral

Adverse Effects (1%)

GI: Diarrhea, nausea, vomiting. Skin: Rash, urticaria. Other: Candidal vaginitis; moderate increases in serum ALT, AST; glomerulonephritis; agranulocytosis (rare).

Diagnostic Test Interference

May interfere with urinary glucose determinations using cupric sulfate, Benedict's solution, Clinitest; does not affect glucose oxidase methods (e.g., Clinistix, TesTape). Positive direct antiglobulin (Coombs') test results may be reported, a reaction that could interfere with hematologic studies or with transfusion cross-matching procedures.

Interactions

Drug: tetracyclines may inhibit activity of amoxicillin; probenecid prolongs the activity of amoxicillin.

Pharmacokinetics

Absorption: Rapid and nearly complete absorption. Peak: 1–2 h. Distribution: Diffuses into most tissues and body fluids, except synovial fluid and CSF (unless meninges are inflamed); crosses placenta; distributed into breast milk in very small amounts. Metabolism: Metabolized in liver. Elimination: 50–73% of the amoxicillin and 25–45% of the clavulanate dose excreted in urine in 2 h. Half-Life: Amoxicillin 1–1.3 h, clavulanate 0.78–1.2 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug