nafcillin

REMS

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.

Action ⬆ ⬇

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

Therapeutic effects:

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.

Pharmacokinetics ⬆ ⬇

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).

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
Nafcillin IM	30 min	60–120 min	4–6 hr
Nafcillin IV	rapid	end of infusion	4–6 hr

Contraind./Precautions ⬆ ⬇

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.

Adv. Reactions/Side Effects ⬆ ⬇

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: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS AND SERUM SICKNESS), superinfection

Interactions ⬆ ⬇

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

Route/Dosage ⬆ ⬇

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.

Availability ⬆ ⬇

(Generic available)

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

Assessment ⬆ ⬇

Assess for infection (vital signs; appearance of wound, sputum, urine, and stool; WBC) at beginning of and throughout therapy.
Obtain a history before initiating therapy to determine previous use of and reactions to cephalosporins or other beta-lactam antibiotics. Persons with a negative history of penicillin sensitivity may still have an allergic response.
Obtain specimens for culture and sensitivity prior to initiating therapy. First dose may be given before receiving results.
Observe patient for signs and symptoms of anaphylaxis (rash, pruritus, laryngeal edema, wheezing, abdominal pain). Discontinue the drug and notify health care professional immediately if these occur. Keep epinephrine, an antihistamine, and resuscitation equipment close by in the event of an anaphylactic reaction.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of Clostridioides difficile-associated diarrhea (CDAD). May begin up to several wk following cessation of therapy.
Assess vein for signs of irritation and phlebitis. Change IV site every 48 hr to prevent phlebitis.

Lab Test Considerations:

May cause leukopenia and neutropenia, especially with prolonged therapy or hepatic impairment.
- May cause positive direct Coombs’ test result.
- May cause ↑ AST, ALT, LDH, and serum alkaline phosphatase concentrations.

Implementation ⬆ ⬇

IV Administration:

IV: IM: To reconstitute, add 3.4 mL to each 1-g vial or 6.8 mL to each 2-g vial, for a concentration of 250 mg/mL. Stable for 2–7 days if refrigerated.
Dilute reconstituted solution with 15–30 mL of sterile water, 0.45% NaCl, or 0.9% NaCl for injection.
Rate: Administer over 5–10 min.
Intermittent Infusion: Diluent: Dilute with sterile water for injection, 0.9% NaCl, D5W, D10W, D5/0.25% NaCl, D5/0.45% NaCl, D5/0.9% NaCl, D5/LR, Ringer’s or LR.Concentration: 2–40 mg/mL. Stable for 24 hr at room temperature, 96 hr if refrigerated.
Rate: Infuse over at least 30–60 min to avoid vein irritation.

Patient/Family Teaching ⬆ ⬇

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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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇