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Index Terms

  • Dicloxacillin Sodium

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

Generic: 250 mg, 500 mg

Pharmacologic Category

  • Antibiotic, Penicillin


Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins (PBPs) which in turn inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thus inhibiting cell wall biosynthesis. Bacteria eventually lyse due to ongoing activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while cell wall assembly is arrested.


Rapid and incomplete; reduced by food


Vd: 5.99 L; increased in patients with ESRD on IHD (Nauta 1976); CSF penetration is low


Feces; urine (as unchanged drug)

Neonates: Prolonged

CF patients: More rapid excretion than healthy patients (Jusko 1975)

Time to Peak

Serum: 1 to 1.5 hours

Half-Life Elimination

~0.7 hours; prolonged with renal impairment (Nauta 1976)

Protein Binding

95% to 99%

Use: Labeled Indications

Staphylococcal infections: Treatment of infections caused by penicillinase-producing staphylococci.


Hypersensitivity to dicloxacillin, other penicillins, or any component of the formulation

Dosing: Adult

Staphylococcal infections: Oral: 125 to 250 mg every 6 hours

Bite wounds (animal) (off-label use): Oral: 500 mg 4 times daily; in combination with penicillin (IDSA [Stevens 2014])

Impetigo (off-label use): Oral: 250 mg 4 times daily for 7 days, depending on response (IDSA [Stevens 2014])

Prosthetic joint infection: Chronic suppression therapy: Staphylococci (oxacillin-susceptible) (off-label dose): Oral: 500 mg every 6 to 8 hours (Osmon 2013)

Skin and soft tissue infection due to MSSA (off-label dose): Oral: 500 mg every 6 hours for 7 to 14 days (IDSA [Stevens 2014])

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Staphylococcal infections: Infants, Children, and Adolescents: Oral:

Weight <40 kg: 12.5 to 25 mg/kg/day divided every 6 hours

Weight ≥40 kg: 125 to 250 mg every 6 hours

Osteoarticular infection (step-down therapy) (off-label dose): Infants, Children, and Adolescents: 100 mg/kg/day divided every 6 hours (Red Book [AAP 2015])

Skin and soft tissue infection due to MSSA (off-label dose): 25 to 50 mg/kg/day divided every 6 hours for 7 to 14 days (IDSA [Stevens 2014])

Dosing: Renal Impairment

There are no specific dosage adjustments provided in the manufacturer's labeling; a reduction in total dosage should be considered in renal impairment.

Hemodialysis: Not dialyzable; supplemental dose is not necessary (Aronoff 2007).

Peritoneal dialysis effects: Supplemental dose is not necessary (Aronoff 2007).

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer's labeling.


Oral: Administer 1 hour before or 2 hours after meals with at least 120 mL of water. Administer around-the-clock to promote less variation in peak and trough serum levels. Should not be administered in the supine position or immediately before going to bed.


Store at 20°C to 25°C (68°F to 77°F).

Drug Interactions

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Avoid combination

Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Monitor therapy

Methotrexate: Penicillins may increase the serum concentration of Methotrexate. Monitor therapy

Mycophenolate: Penicillins may decrease serum concentrations of the active metabolite(s) of Mycophenolate. This effect appears to be the result of impaired enterohepatic recirculation. Monitor therapy

Probenecid: May increase the serum concentration of Penicillins. Management: Avoid the routine use of penicillins and probenecid, but this combination may be used advantageously in select cases with careful monitoring. Monitor for toxic effects of penicillins if probenecid is initiated or the dose is increased. Consider therapy modification

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification

Tetracycline Derivatives: May diminish the therapeutic effect of Penicillins. Consider therapy modification

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents. Consider therapy modification

Vitamin K Antagonists (eg, warfarin): Dicloxacillin may diminish the anticoagulant effect of Vitamin K Antagonists. Monitor therapy

Test Interactions

False-positive urine and serum proteins; false-positive in uric acid, urinary steroids; may interfere with urinary glucose tests using cupric sulfate (Benedict's solution, Clinitest®); may inactivate aminoglycosides in vitro

Adverse Reactions

Frequency not defined.

1% to 10%: Gastrointestinal: Abdominal pain diarrhea, nausea

<1% (Limited to important or life-threatening): Agranulocytosis, eosinophilia, hemolytic anemia, hepatotoxicity, hypersensitivity reaction, interstitial nephritis, leukopenia, neutropenia, prolonged prothrombin time, pseudomembranous colitis, seizure (with extremely high doses and/or renal failure), serum sickness-like reaction, skin rash (maculopapular rash to exfoliative dermatitis), thrombocytopenia, vaginitis, vomiting


Concerns related to adverse effects:

• Hypersensitivity reactions: Serious and occasionally fatal hypersensitivity (anaphylactic shock with collapse) reactions have been reported in patients on penicillin therapy. Initiate therapy only after a comprehensive drug and allergy history; use with caution in patients with a history of significant allergies and/or asthma. Discontinue use and institute appropriate therapy if a hypersensitivity reaction occurs.

• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Neonates: Use with caution in neonates; elimination of drug is slow.

Monitoring Parameters

Baseline and periodic CBC with differential; periodic BUN, serum creatinine, AST and ALT (especially with prolonged therapy); prothrombin time if patient concurrently on warfarin; signs of anaphylaxis during first dose

Pregnancy Risk Factor


Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. Dicloxacillin crosses the placenta (Depp 1970). Maternal use of penicillins has generally not resulted in an increased risk of birth defects.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience diarrhea. Have patient report immediately to prescriber shortness of breath, wheezing, severe nausea, severe vomiting, mouth irritation, tongue discoloration, bruising, bleeding, pharyngitis, joint pain, joint edema, or signs of Clostridium difficile (C. diff)-associated diarrhea (stomach pain or cramps, very loose or watery stools, or bloody stools) (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.