What is the appropriate treatment regimen for a patient with a suspected bacterial infection using Augmentin duo (amoxicillin/clavulanate) considering potential renal impairment and allergy to penicillin?

Augmentin Duo (Amoxicillin/Clavulanate) Treatment Guidelines

Dosing Regimens

For adults with normal renal function, the standard dose is 875 mg/125 mg every 12 hours or 500 mg/125 mg every 8 hours, depending on infection severity. 1

Adult Dosing by Infection Severity

• Mild to moderate infections (ear/nose/throat, skin/soft tissue, genitourinary): 500 mg every 12 hours or 250 mg every 8 hours 1
• Severe infections or lower respiratory tract infections: 875 mg every 12 hours or 500 mg every 8 hours 1
• High-dose regimen for resistant pathogens: 2 g orally twice daily (for community-acquired pneumonia with recent antibiotic exposure) 2

Pediatric Dosing (≥3 months and <40 kg)

• Mild to moderate infections: 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours 1
• Severe infections: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 1
• High-dose formulation (90 mg/6.4 mg/kg/day): For acute otitis media or sinusitis with suspected resistant S. pneumoniae 2, 3

Neonates and Infants (<3 months)

• Maximum dose: 30 mg/kg/day divided every 12 hours due to immature renal function 1

Renal Impairment Adjustments

Patients with GFR <30 mL/min should NOT receive the 875 mg dose. 1

• GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours 1
• GFR <10 mL/min: 500 mg or 250 mg every 24 hours 1
• Hemodialysis: 500 mg or 250 mg every 24 hours, with additional dose during and at end of dialysis 1

Penicillin Allergy Management

Non-Severe Penicillin Allergy (Delayed Rash >1 Year Ago)

First-generation cephalosporins such as cephalexin are safe with only 0.1% cross-reactivity risk. 4

• Cephalexin is the preferred first-line alternative 4
• Cefdinir, cefpodoxime, or cefuroxime are acceptable alternatives for respiratory infections 2

Severe Type I Hypersensitivity (Anaphylaxis, Angioedema, Urticaria)

Clindamycin 300-450 mg orally every 6-8 hours is the first-line alternative for patients with history of anaphylaxis to penicillin. 4

Alternative regimens by infection type:

• Community-acquired pneumonia: Respiratory fluoroquinolone (moxifloxacin, levofloxacin, gatifloxacin) alone 2
• Intra-abdominal infections: Ciprofloxacin 400 mg every 8 hours plus metronidazole 500 mg every 6 hours, or moxifloxacin 400 mg every 24 hours 2
• Acute bacterial rhinosinusitis: TMP/SMX, azithromycin, clarithromycin, or erythromycin (though bacterial failure rates of 20-25% are possible) 2, 4

Critical Caveat on Macrolides

Macrolides have limited effectiveness with resistance rates of 5-8% among common pathogens and should be used cautiously. 4 Monitor for QT prolongation, especially with erythromycin and clarithromycin, and avoid concurrent CYP3A4 inhibitors 4.

Treatment Duration

• Standard bacterial infections: Continue for minimum 48-72 hours beyond symptom resolution or bacterial eradication 1
• Streptococcus pyogenes infections: Minimum 10 days to prevent acute rheumatic fever 1
• Skin and soft tissue infections: 7-10 days 4
• H. pylori eradication: 14 days (triple or dual therapy) 1

Contraindications and Warnings

Amoxicillin/clavulanate is absolutely contraindicated in patients with previous serious hypersensitivity reactions (anaphylaxis, Stevens-Johnson syndrome) to amoxicillin or other β-lactams. 1

• Discontinue immediately if skin rash develops and monitor closely for progression to severe cutaneous adverse reactions (SJS, TEN, DRESS, AGEP) 1
• Serious anaphylactic reactions have occurred with oral penicillins, particularly in patients with history of penicillin hypersensitivity or multiple allergen sensitivities 1

Administration and Storage

• Shake oral suspension well before each use 1
• Reconstituted suspension remains stable for 14 days; refrigeration preferred but not required 1
• Can be mixed with formula, milk, fruit juice, water, or cold drinks for pediatric administration; consume immediately 1