• Treatment of the following infections due to penicillinase-producing staphylococci:
  • Respiratory tract infections,
  • Sinusitis,
  • Skin and skin structure infections,
  • Bone and joint infections,
  • Urinary tract infections,
  • Endocarditis,
  • Bacteremia,
  • Meningitis.

Contraindicated in:

• Previous hypersensitivity to penicillins (cross-sensitivity exists with cephalosporins and other beta-lactam antibiotics).

Use Cautiously in:

• Severe renal or hepatic impairment
• OB: Safety not established in pregnancy.
• Lactation: Use while breastfeeding only if potential maternal benefits justify potential risk to infant.

Derm: rash, urticaria.

GI: diarrhea, epigastric distress, nausea, vomiting, ↑ liver enzymes, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD).

GU: acute kidney injury, hematuria, interstitial nephritis, proteinuria.

Hemat: eosinophilia, leukopenia.

Local: pain at IM site, phlebitis at IV site.

Neuro: SEIZURES.
Misc: (INCLUDING ANAPHYLAXIS AND SERUM SICKNESS)HYPERSENSITIVITY REACTIONS , superinfection.

Drug-Drug:

• Nafcillin may ↓ effectiveness of oral contraceptive agents.
• Probenecid ↓ renal excretion and ↑ blood levels of nafcillin (therapy may be combined for this purpose).
• Concurrent use with methotrexate ↓ methotrexate elimination and ↑ risk of serious toxicity.
• Tetracyclines may ↓ effectiveness of oxacillin

(Generic available)

• Powder for injection: 1 g/vial; 2 g/vial; 10 g/vial;
• Premixed infusion: 1 g/50 mL; 2 g/100 mL;

• IM, IV (Adults): 1–2 g every 4–6 hr.
• IM, IV (Children and Infants): 50–200 mg/kg/day divided every 4–6 hr, maximum: 12 g/day.
• IM, IV (Neonates 0–4 weeks, <1200 g): 50 mg/kg/day divided every 12 hr.
• IV (Adults): 500–2000 mg every 4–6 hr.
• IM, IV (Neonates 1.2–2 kg): —50 mg/kg/day divided every 12 hr for the first 7 days of life, then 75 mg/kg/day divided every 8 hr.
• IM, IV (Neonates >2 kg): —75 mg/kg/day divided every 8 hr for the first 7 days of life, then 100 mg/kg/day divided every 6 hr.

Nallpen

• Bind to bacterial cell wall, leading to cell death. Not inactivated by penicillinase enzymes.

• Bactericidal action.

Spectrum:

• Active against most gram-positive aerobic cocci.
• Spectrum is notable for activity against:
  • Penicillinase-producing strains of Staphylococcus aureus,
  • Staphylococcus epidermidis.
• Not active against methicillin-resistant bacteria.

Therapeutic Classification: anti-infectives

Pharmacologic Classification: penicillinase resistant penicillins

Absorption: Completely absorbed following IV administration; well absorbed from IM sites.

Distribution: Widely distributed; penetration into CSF is minimal but sufficient in the presence of inflamed meninges; cross the placenta and enter breast milk.

Protein Binding: 90% to albumin.

Metabolism/Excretion: Partially metabolized by the liver (60%), partially excreted unchanged by the kidneys.

Half-life: Neonates: 1–5 hr; Children 1 mo – 14 yr: 0.75–1.9 hr; Adults: 0.5–1.5 hr (increased in renal impairment).

• Instruct patient to take medication around the clock and to finish the drug completely as directed, even if feeling better. Missed doses should be taken as soon as remembered. Advise patient that sharing of this medication may be dangerous.
• Advise patient to report signs of superinfection (black, furry overgrowth on the tongue; vaginal itching or discharge; loose or foul-smelling stools) and allergy.
• Instruct patient to notify health care professional if fever and diarrhea develop, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care professional.
• Instruct patient to notify health care professional if symptoms do not improve.

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