Amoxicillin/clavulanate (Augmentin)

Adults: 500 mg orally 2 times per day or 250 mg orally 3 times per day

Children younger than 3 months and less than 40 kg (89 lb): 25 to 45 mg per kg per day (amoxicillin component), divided every 12 hours

Children older than 3 months and 40 kg or more: 30 mg per kg per day, divided every 12 hours

For impetigo; human or animal bites; and MSSA, Escherichia coli, or Klebsiella infections

Common adverse effects: diaper rash, diarrhea, nausea, vaginal mycosis, vomiting

Rare adverse effects: agranulocytosis, hepatorenal dysfunction, hypersensitivity reactions, pseudomembranous enterocolitis

Cefazolin*

Adults: 250 to 500 mg IV or IM every 8 hours (500 to 1,500 mg IV or IM every 6 to 8 hours for moderate to severe infections)

Children: 25 to 100 mg per kg per day IV or IM in 3 or 4 divided doses

For MSSA infections and human or animal bites

Common adverse effects: diarrhea, drug-induced eosinophilia, pruritus

Rare adverse effects: anaphylaxis, colitis, encephalopathy, renal failure, seizure, Stevens-Johnson syndrome

Cephalexin (Keflex)

Adults: 500 mg orally 4 times per day

Children: 25 to 50 mg per kg per day in 2 divided doses

For MSSA infections, impetigo, and human or animal bites; twice-daily dosing is an option

Common adverse effect: diarrhea

Rare adverse effects: anaphylaxis, angioedema, interstitial nephritis, pseudomembranous enterocolitis, Stevens-Johnson syndrome

Clindamycin*

Adults: 150 to 450 mg orally 4 times per day (300 to 450 mg orally 4 times per day for 5 to 10 days for MRSA infection; 600 mg orally or IV 3 times per day for 7 to 14 days for complicated infections)

Children: 16 mg per kg per day in 3 or 4 divided doses (16 to 20 mg per kg per day for more severe infections; 40 mg per kg per day in 3 or 4 divided doses for MRSA infection)

For impetigo; MSSA, MRSA, and clostridial infections; and human or animal bites

Common adverse effects: abdominal pain, diarrhea, nausea, rash

Rare adverse effects: agranulocytosis, elevated liver enzyme levels, erythema multiforme, jaundice, pseudomembranous enterocolitis

Dicloxacillin

Adults: 125 to 500 mg orally every 6 hours (maximal dosage, 2 g per day)

Children less than 40 kg: 12.5 to 50 mg per kg per day divided every 6 hours

Children 40 kg or more: 125 to 500 mg every 6 hours

For MSSA infections

Common adverse effects: diarrhea, impetigo, nausea, vomiting

Rare adverse effects: anaphylaxis, hemorrhagic colitis, hepatorenal toxicity

Doxycycline or minocycline (Minocin)

Adults: 100 mg orally 2 times per day

Children 8 years and older and less than 45 kg (100 lb): 4 mg per kg per day in 2 divided doses

Children 8 years and older and 45 kg or more: 100 mg orally 2 times per day

For MRSA infections and human or animal bites; not recommended for children younger than 8 years

Common adverse effects: myalgia, photosensitivity

Rare adverse effects: Clostridium difficile colitis, hepatotoxicity, pseudotumor cerebri, Stevens-Johnson syndrome

Fluoroquinolones

Adults: ciprofloxacin (Cipro), 500 to 750 mg orally 2 times per day or 400 mg IV 2 times per day; gatifloxacin or moxifloxacin (Avelox), 400 mg orally or IV per day

For human or animal bites; not useful in MRSA infections; not recommended for children

Common adverse effects: diarrhea, headache, nausea, rash, vomiting

Rare adverse effects: agranulocytosis, arrhythmias, hepatorenal failure, tendon rupture

Mupirocin (Bactroban)*

2% ointment applied 3 times per day for 3 to 5 days

For MRSA impetigo and folliculitis; not recommended for children younger than 2 months

Rare adverse effects: burning over application site, pruritus

Retapamulin (Altabax)*

1% ointment applied 2 times per day for 5 days

For MSSA impetigo; not recommended for children younger than 9 months

Rare adverse effects: allergy, angioedema, application site irritation

Trimethoprim/sulfamethoxazole

Adults: 1 or 2 double-strength tablets 2 times per day

Children: 8 to 12 mg per kg per day (trimethoprim component) orally in 2 divided doses or IV in 4 divided doses

For MRSA infections and human or animal bites; contraindicated in children younger than 2 months

Common adverse effects: anorexia, nausea, rash, urticaria, vomiting

Rare adverse effects: agranulocytosis, C. difficile colitis, erythema multiforme, hepatic necrosis, hyponatremia, rhabdomyolysis, Stevens-Johnson syndrome