cloxacillin

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 and Staphylococcus epidermidis.
Not active against methicillin-resistant bacteria (MRSA).

Pharmacokinetics ⬆ ⬇

Absorption: IV administration results in complete bioavailability. Moderately absorbed (50%) following oral administration.

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

Metabolism/Excretion: Some metabolism by the liver (9–22%) and some renal excretion of unchanged drug (20 %).

Half-Life: 0.5–1.1 hr (↑ in severe hepatic impairment, renal impairment, and in neonates).

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
PO	30 min	30–120 min	6 hr
IM	unknown	unknown	6 hr
IV	rapid	end of injection/infusion	6 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

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

Use Cautiously in:

Severe renal or hepatic impairment;
OB: Safety not established;
Pedi: Safety in premature and newborn infants not established.

Adv. Reactions/Side Effects ⬆ ⬇

CNS: SEIZURES

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

GU: interstitial nephritis

Derm: rash, urticaria

Hemat: eosinophilia, leukopenia

Misc: ANAPHYLAXIS AND SERUM SICKNESSALLERGIC REACTIONS INCLUDING , superinfection

Interactions ⬆ ⬇

Drug-drug:

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

Drug-Food:

Food ↓ oral absorption by 50%.

Route/Dosage ⬆ ⬇

PO (Adults ): 250–500 mg every 6 hr.
PO (Children >1 mo ): 50–100 mg/kg/day divided every 6 hr up to a maximum of 4 g/day.
IM IV (Adults ): 250–500 mg every 6 hr, maximum dose 6 g/day
IM IV (Children up to 20 kg): 25–50 mg/kg/day in 4 equally divided doses every 6 hr

Availability ⬆ ⬇

Capsules: 250 mg; 500 mg
Oral solution: 125 mg/5 mL
Powder for injection (requires reconstitution/dilution: 250 mg/vial; 500 mg/vial; 1 g/vial; 2 g/vial

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 no 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 drug and notify health care professional immediately if these occur. Keep epinephrine, an antihistamine, and resuscitation equipment close by in 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.

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 ⬆ ⬇

PO: Administer around the clock on an empty stomach at least 1 hr before or 2 hr after meals. Take with a full glass of water; acidic juices may decrease absorption of penicillins. Swallow capsules whole; do not crush, chew, or open capsules.
- Use calibrated measuring device for liquid preparations. Shake well. Solution is stable for 14 days if refrigerated.
IM: Reconstitute by adding 1.9 mL and 1.7 mL sterile water to 250 mg and 500 mg respectively, for concentrations of 125 mg/mL and 250 mg/mL. Shake well to dissolve. Stable for 24 hr at room temperature or 48 hr if refrigerated.
IV: For IV use, reconstitute 250 mg vial with 4.9 mL, 500 mg vial with 4.8 mL, and 1000 mg vial with 9.6 mL sterile water for concentrations of 50 mg/mL, 100 mg/mL, and 100 mg/mL respectively. Shake well. Use reconstituted solution immediately. Infuse over 2–4 min.
IV: Reconstitute for infusion with sterile water for injection using 3.4 mL for 1000 mg, 6.8 mL for 2000 mg, and 34 mL for 10,000 mg, resulting in 250 mg/mL. Add to an appropriate infusion fluid in amount calculated to give desired dose. Shake well to dissolve. Use solution immediately. Infuse over 30–40 min.
Y-Site Compatibility:
- epinephrine
- ketamine
Y-Site Incompatibility:
- pantoprazole
- rocuronium

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.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Advise patient taking oral contraceptives to use an additional nonhormonal method of contraception during therapy with penicillin and until next menstrual period.
Instruct patient to notify health care professional if symptoms do not improve.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇