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Nafcillin Dosage

Applies to the following strength(s): 250 mg ; 500 mg ; 1 g ; 2 g ; 10 g ; 1 g/50 mL ; 2 g/50 mL ; 2 g/100 mL

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Bacteremia

2 g IV every 4 hours for 14 days depending on the nature and severity of the infection

Usual Adult Dose for Endocarditis

Native valve endocarditis due to staphylococci: Nafcillin 2 g IV every 4 hours or 3 g IV every 6 hours (total 12 g/day) with or without gentamicin 3 mg/kg/day in 2 or 3 divided doses
Duration: Nafcillin, 6 weeks; gentamicin 3 to 5 days

Prosthetic valve endocarditis due to staphylococci: Nafcillin 2 g IV every 4 hours or 3 g IV every 6 hours (total 12 g/day) plus rifampin 300 mg orally every 8 hours, with or without gentamicin 3 mg/kg/day in 2 or 3 divided doses
Duration: Nafcillin and rifampin, 6 weeks or more; gentamicin 2 weeks

Refer to current published guidelines for detailed recommendations.

Usual Adult Dose for Joint Infection

2 g IV every 4 hours for 3 to 4 weeks, depending on the nature and severity of the infection
Longer therapy, for 6 weeks or more, may be required for prosthetic joint infections.

Usual Adult Dose for Meningitis

2 g IV every 4 hours for 14 days

Usual Adult Dose for Osteomyelitis

2 g IV every 4 hours for 4 to 6 weeks, depending on the nature and severity of the infection
Chronic osteomyelitis may require additional oral antibiotic therapy, possibly for up to 6 months.

Usual Adult Dose for Pneumonia

2 g IV every 4 hours
Therapy should continue for up to 21 days depending on the nature and severity of the infection.

Usual Adult Dose for Skin or Soft Tissue Infection

1 to 2 g IV every 4 to 6 hours for 7 days, or for 3 days after acute inflammation resolves, depending on the nature and severity of the infection
More severe infections, such as diabetic soft tissue infections, may require 14 to 21 days of therapy.

Usual Pediatric Dose for Pharyngitis

The safety and efficacy of nafcillin when administered IV in neonates and children have not been established. However, the use of nafcillin IV may be appropriate in some situations.

0 to 4 weeks, birthweight 1199 g or less: 25 mg/kg IV or IM every 12 hours

7 days or less:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 12 hours
birthweight 2001 g or more: 25 mg/kg IV or IM every 8 hours

8 days up to 1 month:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 8 hours
birthweight 2001 g or more: 25 to 35 mg/kg IV or IM every 6 hours

1 month to 18 years:
Mild to moderate infections: 12.5 to 25 mg/kg IV or IM every 6 hours
Severe infections: 100 to 200 mg/kg/day IV in equally divided doses every 4 to 6 hours

Maximum dose: 12 g/day

Usual Pediatric Dose for Pneumonia

The safety and efficacy of nafcillin when administered IV in neonates and children have not been established. However, the use of nafcillin IV may be appropriate in some situations.

0 to 4 weeks, birthweight 1199 g or less: 25 mg/kg IV or IM every 12 hours

7 days or less:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 12 hours
birthweight 2001 g or more: 25 mg/kg IV or IM every 8 hours

8 days up to 1 month:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 8 hours
birthweight 2001 g or more: 25 to 35 mg/kg IV or IM every 6 hours

1 month to 18 years:
Mild to moderate infections: 12.5 to 25 mg/kg IV or IM every 6 hours
Severe infections: 100 to 200 mg/kg/day IV in equally divided doses every 4 to 6 hours

Maximum dose: 12 g/day

Usual Pediatric Dose for Bacterial Infection

The safety and efficacy of nafcillin when administered IV in neonates and children have not been established. However, the use of nafcillin IV may be appropriate in some situations.

0 to 4 weeks, birthweight 1199 g or less: 25 mg/kg IV or IM every 12 hours

7 days or less:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 12 hours
birthweight 2001 g or more: 25 mg/kg IV or IM every 8 hours

8 days up to 1 month:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 8 hours
birthweight 2001 g or more: 25 to 35 mg/kg IV or IM every 6 hours

1 month to 18 years:
Mild to moderate infections: 12.5 to 25 mg/kg IV or IM every 6 hours
Severe infections: 100 to 200 mg/kg/day IV in equally divided doses every 4 to 6 hours

Maximum dose: 12 g/day

Usual Pediatric Dose for Skin and Structure Infection

The safety and efficacy of nafcillin when administered IV in neonates and children have not been established. However, the use of nafcillin IV may be appropriate in some situations.

0 to 4 weeks, birthweight 1199 g or less: 25 mg/kg IV or IM every 12 hours

7 days or less:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 12 hours
birthweight 2001 g or more: 25 mg/kg IV or IM every 8 hours

8 days up to 1 month:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 8 hours
birthweight 2001 g or more: 25 to 35 mg/kg IV or IM every 6 hours

1 month to 18 years:
Mild to moderate infections: 12.5 to 25 mg/kg IV or IM every 6 hours
Severe infections: 100 to 200 mg/kg/day IV in equally divided doses every 4 to 6 hours

Maximum dose: 12 g/day

Usual Pediatric Dose for Endocarditis

Native valve endocarditis due to staphylococci: 200 mg/kg/day IV in equally divided doses every 4 to 6 hours for 6 weeks

Prosthetic valve endocarditis due to staphylococci: 200 mg/kg/day IV in equally divided doses every 4 to 6 hours for 6 weeks or longer with rifampin and gentamicin for the first 2 weeks of therapy

Maximum dose: 12 g/day

Refer to current published guidelines for detailed recommendations.

Renal Dose Adjustments

For patients with both severe renal and hepatic impairment, the dose used should be the lower range of the usual dose or reduced by 33% to 50%, or the frequency may be reduced.

Liver Dose Adjustments

For patients with both severe renal and hepatic impairment, the dose used should be the lower range of the usual dose or reduced by 33% to 50%, or the frequency may be reduced.

Precautions

Serious and occasionally fatal hypersensitivity reactions have been reported with antibiotics. The drug should be discontinued immediately at the first appearance of a skin rash or other signs of hypersensitivity. Severe, acute hypersensitivity reactions may require treatment with epinephrine and other resuscitative measures including oxygen, intravenous fluids, antihistamines, corticosteroids, cardiovascular support and airway management as clinically indicated.

Clostridium difficile associated diarrhea (CDAD) has been reported with almost all antibiotics and may potentially be life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea following nafcillin therapy. Mild cases generally improve with discontinuation of the drug, while severe cases may require supportive therapy and treatment with an antimicrobial agent effective against C difficile. Hypertoxin producing strains of C difficile cause increased morbidity and mortality; these infections can be resistant to antimicrobial treatment and may necessitate colectomy.

Solutions containing dextrose may be contraindicated with patients with known allergies to corn or corn products.

Caution is recommended in patients with asthma or history of allergies.

The IV route of administration should be used for relatively short term therapy (24 to 48 hours) because of the occasional occurrence of thrombophlebitis, particularly in elderly patients. Extravasation may result in tissue necrosis, ulceration, sloughing, and gangrene, and should be avoided. If the patient experiences pain during administration, the infusion should be stopped and the patient evaluated for thrombophlebitis and extravasation.

Nafcillin injection contains 3.33 mEq sodium per gram. This may be significant for elderly patients or in conditions such as congestive heart failure. Monitoring of cardiac, vascular, and electrolyte status is recommended.

Periodic monitoring of renal, hepatic, and hematologic function is recommended during prolonged therapy.

Nafcillin may cause false-positive results for urine protein by the sulfosalicylic acid test.

There are no approved dosing regimens for the IV route of administration in neonates and children.

Because of immature hepatic and renal function in newborns, nafcillin excretion may be decreased in neonates. Use with extreme caution in neonates less than 2 weeks old and consider monitoring serum levels.

Dialysis

Nafcillin is not dialyzable.

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