What is the recommended dosage of Amoxiclav (amoxicillin-clavulanate) for children and adults?

Amoxicillin-Clavulanate (Amoxiclav) Dosing Guidelines

For adults with respiratory tract infections, the recommended dose is 875 mg/125 mg twice daily, while children require weight-based dosing of 45-90 mg/kg/day of the amoxicillin component divided into 2 doses, with the higher dose (90 mg/kg/day) indicated for resistant organisms or specific risk factors. 1, 2, 3

Adult Dosing

Standard Regimens

• For severe infections and respiratory tract infections: 875 mg/125 mg tablet every 12 hours 3
• For mild to moderate infections: 500 mg/125 mg every 8 hours 2
• For high-risk respiratory infections (recent antibiotic use, treatment failure, resistant pathogens): 2 g/125 mg twice daily 2
• Treatment duration: 5-7 days for uncomplicated acute bacterial rhinosinusitis, 14 days for bronchiectasis exacerbations 2

Administration Considerations

• May be taken without regard to meals, though absorption of clavulanate is enhanced when taken at the start of a meal 3
• To minimize gastrointestinal intolerance, administer at the start of a meal 3

Renal Impairment

• Patients with glomerular filtration rate <30 mL/min should not receive the 875 mg dose 3

Pediatric Dosing

Standard Dose Regimen

• 45 mg/kg/day of amoxicillin component with 6.4 mg/kg/day of clavulanate, divided into 2 doses 1, 2
• Maximum single dose: 2 grams regardless of weight 1

High-Dose Regimen (90 mg/kg/day)

The high-dose regimen (90 mg/kg/day amoxicillin with 6.4 mg/kg/day clavulanate in 2 divided doses) is specifically indicated for children with any of the following risk factors: 1

• Age <2 years 1
• Daycare attendance 1, 2
• Recent antibiotic use within 30 days 1, 2
• Moderate to severe illness 1
• Areas with high prevalence (>10%) of penicillin-resistant Streptococcus pneumoniae 1, 2
• Incomplete Haemophilus influenzae type b vaccination (<3 injections) 1
• Concurrent purulent otitis media or conjunctivitis 1, 2
• Treatment failure with standard amoxicillin 1

Age-Based Oral Suspension Dosing (Standard Dose)

• <1 year (1-12 months): 2.5 mL of 125/31 suspension three times daily 1
• 1-6 years: 5 mL of 125/31 suspension three times daily 1
• 7-12 years: 5 mL of 250/62 suspension three times daily 1
• 12-18 years: 1 tablet (250/125) three times daily 1

Intravenous Dosing

• 30 mg/kg three times daily IV for all pediatric ages 1

Critical Clinical Considerations

Why High-Dose Matters

• The 14:1 ratio formulation (90/6.4 mg/kg/day) causes less diarrhea than other amoxicillin-clavulanate preparations while maintaining efficacy 1, 2
• High-dose amoxicillin (80-90 mg/kg/day) exceeds the minimum inhibitory concentration for intermediately resistant S. pneumoniae and many highly resistant serotypes 1
• Standard doses (40 mg/kg/day) are inadequate to effectively eradicate resistant Streptococcus pneumoniae, particularly during viral coinfection 4
• Middle ear fluid concentrations with high-dose therapy are adequate to overcome penicillin-resistant S. pneumoniae 1

Common Pitfalls to Avoid

• Verify suspension concentration (125/31 vs 250/62) before calculating volume to avoid dosing errors 1
• Using standard doses when high-dose therapy is indicated leads to treatment failure with resistant organisms 1
• Subtherapeutic doses fail to achieve adequate serum and tissue concentrations and promote antimicrobial resistance 1
• Most upper respiratory tract infections are viral and do not require antibiotics at all 1

Specific Infection Types

Skin and Soft Tissue Infections

• Impetigo (adults): 875/125 mg twice daily 5
• Impetigo (children): 25 mg/kg/day of amoxicillin component in 2 divided doses 5

Intra-Abdominal Infections (Pediatric)

• Ampicillin-sulbactam: 200 mg/kg/day of ampicillin component every 6 hours IV 5
• Ticarcillin-clavulanate: 200-300 mg/kg/day of ticarcillin component every 4-6 hours IV 5

Community-Acquired Pneumonia (Children)

• For presumed bacterial pneumonia in children <5 years: 90 mg/kg/day in 2 doses 1
• For children <3 years: start with amoxicillin alone at 80-100 mg/kg/day in 3 divided doses, add clavulanate if necessary 1
• Treatment duration: 10 days for bacterial pneumonia 1

Pharmacokinetic Considerations

• Peak amoxicillin concentrations occur approximately 1-1.5 hours after oral dosing 3
• Middle ear fluid concentration peak occurs approximately 3 hours after dosing 4
• Amoxicillin serum concentrations increase linearly with dose, and the difference in adverse effects between lower and higher doses is generally negligible 1
• Viral coinfection in acute otitis media reduces antibacterial efficacy and lowers middle ear fluid penetration 4