Reviewed on 3/16/2022

Generic Name: Oxacillin

Brand Name: Bactocill

Drug Class: Penicillins, Penicillinase-Resistant

What Is Oxacillin and How Does It Work?

Oxacillin is a prescription medication used for the treatment of staphylococcal infection.

  • Oxacillin is available under the following different brand names: Bactocill

What Are Dosages of Oxacillin?

Adult and pediatric dosage

Infusion solution

  • 1g/50mL
  • 2g/50mL

Powder for injection

  • 1g
  • 2g
  • 10g

Staphylococcal Infections

Adult dosage

  • Mild to moderate infections: 250-500 mg IV/IM every 4-6 hours
  • Severe infections: 1 g IV/IM every 4-6 hours
  • Acute/chronic osteomyelitis/staphylococci infections: 1.5-2 g IV every 4-6 hours
  • Susceptible Staph Infections in Infants & Children

Pediatric dosage

  • Mild to moderate infections: 100-200 mg/kg/day IV/IM divided every 6 hours 
  • Severe infections: 150-200 mg/kg/day IV/IM divided every 6 hours
  • Maximum 4g/day for mild to moderate infections
  • Maximum 12g/day for severe infections
  • Susceptible Staph Infections in Neonates

Pediatric dosage

  • (children less than 7 days old and weighing below 2 kg) OR (children above 7 days old and weighing less than 1.2 kg): 50 mg/kg/day divided every 12 hours IV/IM  
  • (Children above 7 days old and weighing above 2 kg) OR (children above 7 days old and weighing between 1.2-2 kg): 75 mg/kg/day divided every 8 hours IV/IM
  • Children above 7 days old and weighing above 2 kg: 100 mg/kg/day divided every 6 hours IV/IM

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Oxacillin?

Common side effects of Oxacillin include:

  • injection site pain
  • nausea
  • muscle, joint, and bone pain
  • headache
  • back pain
  • tiredness
  • pain in arms, hands, legs, or feet
  • hot flashes
  • vomiting
  • loss of appetite
  • weakness
  • cough
  • shortness of breath
  • constipation
  • increased liver enzymes
  • diarrhea

Serious side effects of Oxacillin include:

  • signs of an allergic reaction: hives, itching; wheezing, difficult breathing; feeling light-headed, swelling of the face, lips, tongue, or throat, 
  • severe stomach pain,
  • watery  or bloody diarrhea,
  • nausea, vomiting,
  • bruising or swelling around the IV needle,
  • kidney problems--little or no urination, painful or difficult urination, red or pink urine;
  • liver problems--nausea, upper stomach pain, itching, tiredness, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
  • low white blood cell counts--fever, chills, sore throat, swollen gums, mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough, trouble breathing.

Rare side effects of Oxacillin include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.


MRSA Infection: Causes, Symptoms, and Treatment See Slideshow

What Other Drugs Interact with Oxacillin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Oxacillin?


  • Allergy to penicillins, cephalosporins, imipenem
  • Solutions containing dextrose may be contraindicated in patients with known allergies to corn or corn products

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Oxacillin?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Oxacillin?”


  • Evaluate renal, hepatic, hematologic systems periodically during prolonged treatment
  • Monitor neonates for renal impairment
  • Monitor organ systems/serum concentrations of drugs in neonates
  • Prolonged treatment may result in bacterial or fungal superinfection
  • Clostridium difficile associated diarrhea (CDAD) must be considered in all patients who present with diarrhea following antibiotic; CDAD has been reported to occur over two months after the administration of antibacterial agents; careful medical history is necessary; if CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued; appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as indicated

Pregnancy and Lactation

  • May be acceptable during pregnancy


  • Excreted in breast milk; use caution
Medscape. Oxacillin.


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