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Uses

Staphylococcal Infections

Treatment of infections caused by, or suspected of being caused by, susceptible penicillinase-producing staphylococci, including respiratory tract, skin and skin structure, bone and joint, and urinary tract infections and meningitis or bacteremia. A drug of choice for these infections.

Treatment of native valve or prosthetic valve endocarditis caused by susceptible staphylococci. A drug of choice; used with or without gentamicin for native valve endocarditis and used in conjunction with rifampin and gentamicin for prosthetic valve endocarditis.

If used empirically, consider whether staphylococci resistant to penicillinase-resistant penicillins (oxacillin-resistant [methicillin-resistant] staphylococci) are prevalent in the hospital or community. (See Staphylococci Resistant to Penicillinase-resistant Penicillins under Cautions.)

Perioperative Prophylaxis

Has been used for perioperative prophylaxis† in patients undergoing neurosurgery or cardiovascular or orthopedic surgery associated with high risk of staphylococcal infections. Not considered a drug of choice.

Dosage and Administration

Administration

Administer by IV injection or infusion or by IM injection.

To reduce risk of thrombophlebitis and other adverse local reactions associated with IV administration (particularly in geriatric patients), administer slowly and take care to avoid extravasation.

IV Injection

Reconstitution

Reconstitute vials containing 1 or 2 g of oxacillin by adding 10 or 20 mL, respectively, of sterile water for injection or 0.45 or 0.9% sodium chloride injection to provide solutions containing approximately 100 mg/mL.

Rate of Administration

Inject appropriate dose slowly over a period of about 10 minutes.

IV Infusion

Reconstitution and Dilution

Reconstitute vials containing 1 or 2 g of oxacillin by adding 10 or 20 mL, respectively, of sterile water for injection or 0.45 or 0.9% sodium chloride injection to provide a solution containing approximately 100 mg/mL. Reconstituted solution should then be further diluted with a compatible IV solution (see Solution Compatibility under Stability) to a concentration of 0.5–40 mg/mL.

Alternatively, ADD-Vantage^® vials containing 1 or 2 g of the drug should be reconstituted according to the manufacturer’s directions.

Reconstitute 10-g pharmacy bulk package with 93 mL of sterile water for injection or 0.9% sodium chloride injection to provide a solution containing 100 mg/mL. Pharmacy bulk packages of the drug are not intended for direct IV infusion; prior to administration, doses of the drug from the reconstituted pharmacy bulk package must be further diluted in a compatible IV infusion solution (see Solution Compatibility under Stability).

Thaw the commercially available injection (frozen) at room temperature or in a refrigerator; do not force thaw by immersion in a water bath or by exposure to microwave radiation. A precipitate may have formed in the frozen injection, but should dissolve with little or no agitation after reaching room temperature. Discard thawed injection if an insoluble precipitate is present or if container seals or outlet ports are not intact. Additives should not be introduced into the injection. The injections should not be used in series connections with other plastic containers, since such use could result in air embolism from residual air being drawn from the primary container before administration of fluid from the secondary container is complete.

Rate of Administration

The rate of IV infusion should be adjusted so that the total dose is administered before the drug is inactivated in the IV solution.

IM Administration

Inject IM deeply into a large muscle (e.g., gluteus maximus) avoiding sciatic nerve injury.

Reconstitution

For IM injection, reconstitute vial containing 1 or 2 g of oxacillin by adding 5.7 or 11.4 mL, respectively, of sterile water for injection to provide solutions containing 167 mg/mL (250 mg/1.5 mL). Shake vial well until a clear solution is obtained.

Dosage

Available as oxacillin sodium; dosage expressed in terms of oxacillin.

Duration of treatment depends on type and severity of infection and should be determined by clinical and bacteriologic response of the patient. For serious staphylococcal infections, duration usually is ≥1–2 weeks; more prolonged therapy is necessary for treatment of osteomyelitis or endocarditis.

Pediatric Patients

Staphylococcal Infections

General Dosage in Neonates

IV or IM

25 mg/kg daily recommended by manufacturer.

Neonates <1 week of age: AAP recommends 25 mg/kg every 12 hours for those weighing <1.2 kg; 25–50 mg/kg every 12 hours for those weighing 1.2 to 2 kg; and 25–50 mg/kg every 8 hours for those weighing >2 kg. The higher dosages are recommended for meningitis.

Neonates 1–4 weeks of age: AAP recommends 25 mg/kg every 12 hours for those weighing <1.2 kg; 25–50 mg/kg every 8 hours for those weighing 1.2 to 2 kg; and 25–50 mg/kg every 6 hours for those weighing >2 kg. The higher dosages are recommended for meningitis.

Mild to Moderate Infections in Infants and Children

IV or IM

Children weighing <40 kg: 50 mg/kg daily given in equally divided doses every 6 hours.

Children weighing ≥40 kg: 250–500 mg every 4–6 hours.

Children ≥1 month of age: AAP recommends 100–150 mg/kg daily in 4 divided doses.

Severe Infections in Infants and Children

IV or IM

Children weighing <40 kg: 100–200 mg/kg daily given in equally divided doses every 4–6 hours.

Children weighing ≥40 kg: 1 g every 4–6 hours.

Children ≥1 month of age: AAP recommends 150–200 mg/kg daily in 4–6 divided doses.

Staphylococcal Native Valve Endocarditis

IV

AHA recommends 200 mg/kg daily given in divided doses every 4–6 hours for 6 weeks (maximum 12 g daily).

In addition, during the first 3–5 days of oxacillin therapy, IM or IV gentamicin (3 mg/kg daily given in divided doses every 8 hours; dosage adjusted to achieve peak serum gentamicin concentrations approximately 3 mcg/mL and trough concentrations <1 mcg/mL) may be given concomitantly if the causative organism is susceptible to the drug.

Staphylococcal Prosthetic Valve Endocarditis

IV

AHA recommends 200 mg/kg daily given in divided doses every 4–6 hours for 6 weeks or longer (maximum 12 g daily).

Used in conjunction with oral rifampin (20 mg/kg daily given in divided doses every 8 hours for 6 weeks or longer) and IM or IV gentamicin (3 mg/kg daily given in divided doses every 8 hours during the first 2 weeks of oxacillin therapy; dosage adjusted to achieve peak serum gentamicin concentrations approximately 3 mcg/mL and trough concentrations <1 mcg/mL).

Adults

Staphylococcal Infections

Mild to Moderate Infections

IV or IM

250–500 mg every 4–6 hours.

Severe Infections

IV or IM

1 g every 4–6 hours.

Acute or Chronic Staphylococcal Osteomyelitis

IV

1.5–2 g every 4 hours.

When used for treatment of acute or chronic osteomyelitis caused by susceptible penicillinase-producing staphylococci, parenteral therapy generally continued for 3–8 weeks; follow-up with an oral penicillinase-resistant penicillin (e.g., dicloxacillin) generally recommended. In treatment of acute osteomyelitis, a shorter course of parenteral penicillinase-resistant therapy (5–28 days) followed by 3–6 weeks of oral penicillinase-resistant penicillin therapy also has been effective.

Staphylococcal Native Valve Endocarditis

IV

AHA recommends 2 g every 4 hours for 4–6 weeks.

Although benefits of concomitant aminoglycosides have not been clearly established, AHA states that IM or IV gentamicin (1 mg/kg every 8 hours) may be given concomitantly during the first 3–5 days of oxacillin therapy.

Staphylococcal Prosthetic Valve Endocarditis

IV

AHA recommends 2 g every 4 hours for ≥6 weeks in conjunction with oral rifampin (300 mg every 8 hours for 6 weeks or longer) and IM or IV gentamicin (1 mg/kg every 8 hours during the first 2 weeks of oxacillin therapy). (See Staphylococci Resistant to penicillinase-resistant Penicillins under Cautions.)

Staphylococcal Infections Related to Intravascular Catheters

IV

2 g every 4 hours.

Special Populations

Dosage in Renal Impairment

Modification of dosage generally is unnecessary in patients with renal impairment; some clinicians suggest that the lower range of the usual dosage (1 g IM or IV every 4–6 hours) be used in adults with Cl_cr <10 mL/minute.