Oxacillin Injection
Oxacillin Injection is a penicillin-type antibiotic used to treat serious bacterial infections caused by penicillinase-producing staphylococci.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 9 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Oxacillin Injection: Patient Information Guide
A plain-language walkthrough of Oxacillin Injection — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Oxacillin Injection is a penicillin-type antibiotic used specifically against staph bacteria that resist ordinary penicillin.
- Treats infections caused by penicillinase-producing staphylococci — staph strains that produce an enzyme to break down standard penicillin
- Can be used to start treatment when a resistant staph infection is strongly suspected, even before lab confirmation
- Treats serious staph infections such as endocarditis (infection of the heart valves) and osteomyelitis (bone infection), which may need longer courses
- Should not be used for infections caused by organisms that are still susceptible to regular penicillin G, or for infections caused by non-staph organisms
⚙️How it works▾
Oxacillin kills bacteria by interfering with their ability to build and maintain their cell walls. Without a strong cell wall, bacteria fall apart and die. This action happens while bacteria are actively growing and dividing, so the drug is most effective against rapidly multiplying staph bacteria. Because it is structurally resistant to the penicillinase enzyme that staph produce, it stays active where regular penicillin would be destroyed.
Bacteria can still develop resistance to oxacillin through other mechanisms — such as changing the target the drug binds to, or preventing the drug from getting inside the cell. If a staph strain is resistant to oxacillin, it is also considered resistant to all other beta-lactam antibiotics (a large class that includes most penicillins and cephalosporins), with the exception of some newer agents designed specifically for resistant strains.
💊How it's taken▾
Oxacillin Injection is given by a healthcare provider either directly into a vein (IV) or into a muscle (IM). It is typically administered multiple times throughout the day, every four to six hours, with the exact schedule and duration determined by your care team based on the type and severity of infection.
- For severe infections, treatment generally continues for at least 14 days
- Treatment should continue for at least 48 hours after you are fever-free, symptom-free, and cultures are negative
- Conditions like endocarditis or osteomyelitis may require an even longer course
Follow your prescriber's instructions precisely — completing the full course is important even if you feel better early.
🤒Side effects — in detail▾
Like all antibiotics, oxacillin can cause side effects ranging from mild to serious.
- Allergic reactions — hives, itching, rash, or fever
- Nausea, vomiting, or diarrhea
- Black or hairy tongue
- Vein irritation (thrombophlebitis) with IV use, especially in older adults
- Elevated liver enzymes (detected on blood tests)
- Decreased white blood cell count — agranulocytosis or neutropenia
- Kidney inflammation (interstitial nephritis) — may show as blood or protein in the urine
- Nervous system effects such as twitching or neurotoxicity with high IV doses, especially in patients with kidney problems
Seek emergency care immediately if you develop difficulty breathing, throat tightening, or sudden collapse — these are signs of a life-threatening allergic reaction. Also contact your doctor right away for severe or persistent diarrhea, which may indicate a serious C. difficile bowel infection.
⚠️Warnings & precautions▾
- Severe allergic reactions (anaphylaxis): Oxacillin and all penicillins can cause rare but potentially fatal allergic reactions, including cardiovascular collapse. Anyone with a known penicillin allergy must not receive oxacillin. People with cephalosporin allergies may also be at risk. Emergency resuscitation equipment should be available during administration.
- C. difficile colitis: Antibiotic use can disrupt normal gut bacteria, allowing C. difficile to overgrow and cause serious colon inflammation. Symptoms — including severe diarrhea — can appear during treatment or up to two months after finishing the antibiotic. Prompt medical evaluation is essential.
- Kidney and liver monitoring: Prolonged use of oxacillin can affect kidney and liver function. Regular blood and urine tests are recommended during treatment, and dose adjustments may be needed if problems develop.
- Blood cell monitoring: Oxacillin has been associated with low white blood cell counts (neutropenia, agranulocytosis) and bone marrow suppression. Blood counts should be checked before and during therapy.
🔀What it interacts with▾
Oxacillin has a small but important list of drug interactions to be aware of.
- Tetracycline antibiotics: These work in a different way than oxacillin (they slow bacterial growth rather than killing bacteria outright). Using both together can reduce oxacillin's effectiveness — this combination should be avoided.
- Probenecid (a gout medication): This drug blocks the kidneys from clearing oxacillin, which raises oxacillin blood levels and keeps them elevated longer. This interaction is generally avoided unless very high oxacillin levels are specifically needed for a difficult infection.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Tell your doctor if you have ever had any allergic reaction to a penicillin or cephalosporin antibiotic — oxacillin cannot be used if you have had a serious penicillin allergy
- Tell your doctor if you have kidney disease — dose adjustments and closer monitoring may be needed to prevent toxic effects
- Tell your doctor if you have liver disease — oxacillin can affect liver function and requires periodic liver enzyme monitoring
- Tell your doctor if you are allergic to corn or corn products, as some oxacillin solutions contain dextrose (a corn-derived sugar)
- Tell your doctor about all medications you take, especially tetracyclines or probenecid
- Older adults receiving IV oxacillin should be monitored for vein irritation (thrombophlebitis) at the injection site
- Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding so the risks and benefits can be discussed
🚑If you take too much▾
If too much oxacillin is given, symptoms are generally those described under side effects — particularly effects on the nervous system, kidneys, and gastrointestinal tract. If an overdose is suspected, the medication should be stopped right away, and supportive medical care should be provided to manage symptoms. Contact a poison control center or emergency services immediately if an overdose is suspected.
📡Pharmacodynamics — effects in the body▾
Oxacillin kills susceptible staphylococcal bacteria by blocking the construction of their cell walls. It is active specifically when bacteria are multiplying — it does not have activity against resting or dormant bacteria. Because it is structurally designed to resist the penicillinase enzyme, it retains this killing activity against staph strains that would destroy ordinary penicillin. Its bactericidal (bacteria-killing, rather than just bacteria-slowing) action is why it is preferred for serious staph infections.
🔬Pharmacokinetics — how your body processes it▾
When given intravenously (into a vein), oxacillin reaches its peak level in the blood within about 5 minutes of the injection finishing. When given intramuscularly (into a muscle), peak levels are reached in about 30 minutes. The drug is cleared quickly — its half-life (the time for blood levels to drop by half) is roughly 30 minutes. Oxacillin is eliminated primarily through the kidneys, but the liver also plays a role in processing and excreting it through bile. It binds strongly to proteins in the blood (about 94%), which affects how it distributes throughout the body — it does not reach significant levels in the fluid around the brain or spine under normal dosing.
📦How to store it▾
Store dry powder at 20° to 25°C (68° to 77°F) .
📄 Written from Oxacillin Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Oxacillin Injection
56 supplements and herbal products have documented interactions with Oxacillin Injection in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 3
- Moderate · 42
- Minor · 11
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Nutrient depletion considerations
Oxacillin Injection has been associated with lower levels of 7 nutrients in the clinical literature. This does not mean a deficiency will occur — it means these may be worth discussing with your pharmacist or healthcare provider, especially with long-term use.
- Higher significance · 6
- Moderate · 1
Educational information from a licensed clinical database (Natural Medicines) — not medical advice. Do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Oxacillin Injection — the kind of thing our pharmacy team would talk through with you at the counter.
Why am I getting oxacillin instead of a regular penicillin? ▾
How long will I need to be on this antibiotic? ▾
What side effects should I watch out for while on oxacillin? ▾
I've heard penicillin can cause allergic reactions — how will my care team keep me safe? ▾
Are there any medications I need to avoid while taking oxacillin? ▾
Why do I need blood and urine tests while on oxacillin? ▾
Is Oxacillin Injection available over the counter? ▾
When was Oxacillin Injection first available? ▾
Who makes Oxacillin Injection? ▾
💬 Answers drafted from Oxacillin Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Oxacillin Injection comes
Oxacillin Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- OXACILLIN Injection is used to treat infections caused by penicillinase-producing staphylococci confirmed or strongly suspected to be susceptible to the drug
- OXACILLIN Injection may be started before lab results are available when a resistant staph infection is strongly suspected
- OXACILLIN Injection is used for serious infections including endocarditis and osteomyelitis, which may require longer courses of treatment
- OXACILLIN Injection is given intravenously (into a vein) or intramuscularly (into a muscle) by a trained healthcare provider
- OXACILLIN Injection is typically given in divided doses throughout the day; the exact schedule depends on the severity of the infection and your overall condition
- OXACILLIN Injection should not be mixed in the same IV line with other medications — any additional drugs should be given separately
- Treatment with OXACILLIN Injection should continue for at least 48 hours after symptoms resolve and cultures are negative; severe infections typically require at least 14 days
Show 2 more strengths Show fewer strengths
📊 Oxacillin Injection across the U.S. market
How Oxacillin Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Oxacillin Injection is used
A general measure of how commonly Oxacillin Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Oxacillin Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Oxacillin Injection prescribed? Of the 1,594 medications we measure, Oxacillin Injection ranks #1,211 by Medicaid prescriptions — more than 24% of them.
Utilization by Oxacillin Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
oxacillin 100 MG/ML Injectable Solution Most dispensed
Summed across the 2 of 15 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 312127
oxacillin 2000 MG Injection
Summed across the 4 of 15 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1743549
oxacillin 1000 MG Injection
Summed across the 1 of 12 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1743547
50 ML oxacillin 40 MG/ML Injection
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 240637
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Oxacillin Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 8 of 43 listed Oxacillin Injection NDCs with Medicaid activity.
🔍 Compare Oxacillin Injection products
A representative set of FDA-listed product records for Oxacillin Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 2 g | Intramuscular, Intravenous | Armas Pharmaceuticals Inc. | ANDA | View NDC → |
| 2 g | Intramuscular; Intravenous | Armas Pharmaceuticals Inc. × 2 listings | ANDA | View NDC → |
| 1 g | Intramuscular; Intravenous | AuroMedics Pharma LLC | ANDA | View NDC → |
| 2 g | Intramuscular; Intravenous | AuroMedics Pharma LLC | ANDA | View NDC → |
| 10 g/100 mL | Intravenous | AuroMedics Pharma LLC | ANDA | View NDC → |
| 1 g/50 mL | Intravenous | Baxter Healthcare Corporation × 2 listings | NDA | View NDC → |
| 2 g/50 mL | Intravenous | Baxter Healthcare Corporation × 5 listings | NDA | View NDC → |
| 1 g | Intramuscular, Intravenous | Eugia US LLC | ANDA | View NDC → |
| 1 g | Intramuscular; Intravenous | Eugia US LLC | ANDA | View NDC → |
| 2 g | Intramuscular, Intravenous | Eugia US LLC | ANDA | View NDC → |
| 2 g | Intramuscular; Intravenous | Eugia US LLC | ANDA | View NDC → |
| 10 g/100 mL | Intravenous | Eugia US LLC × 2 listings | ANDA | View NDC → |
| 1 g/20 mL | Intramuscular, Intravenous | Fresenius Kabi USA, LLC | ANDA | View NDC → |
| 2 g/20 mL | Intramuscular, Intravenous | Fresenius Kabi USA, LLC | ANDA | View NDC → |
| 10 g/100 mL | Intravenous | Fresenius Kabi USA, LLC | ANDA | View NDC → |
| 1 g | Intramuscular, Intravenous | Onesource Specialty Pharma Limited | ANDA | View NDC → |
| 2 g | Intramuscular, Intravenous | Onesource Specialty Pharma Limited | ANDA | View NDC → |
| 10 g/10 g | Intravenous | Piramal Critical Care Inc | ANDA | View NDC → |
| 1 g | Intramuscular; Intravenous | Sagent Pharmaceuticals | ANDA | View NDC → |
| 2 g | Intramuscular; Intravenous | Sagent Pharmaceuticals × 2 listings | ANDA | View NDC → |
| 10 g/100 mL | Intravenous | Sagent Pharmaceuticals × 2 listings | ANDA | View NDC → |
| 2 g | Intramuscular; Intravenous | Steriscience Specialties Private Limited | ANDA | View NDC → |
| 1 g/20 mL | Intramuscular, Intravenous | Wockhardt USA LLC. | ANDA | View NDC → |
| 1 g/20 mL | Intramuscular; Intravenous | Wockhardt USA LLC. × 2 listings | ANDA | View NDC → |
| 2 g/20 mL | Intramuscular, Intravenous | Wockhardt USA LLC. | ANDA | View NDC → |
| 2 g/20 mL | Intramuscular; Intravenous | Wockhardt USA LLC. × 2 listings | ANDA | View NDC → |
| 10 g/100 mL | Intravenous | Wockhardt USA LLC. × 3 listings | ANDA | View NDC → |
Showing 40 of 40 products — FDA National Drug Code Directory. See every product, package size and price: browse all 40 Oxacillin Injection NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Oxacillin Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Oxacillin Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Oxacillin Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 7773 4 dose forms · 8 strengths
-
Dose form (SCDF) Injectable Solution RxCUI 376698In current FDA listingsClinical drug / strength (SCD) 100 MG/MLRxCUI 312127 -
Dose form (SCDF) Injection RxCUI 1743541In current FDA listingsClinical drug / strength (SCD) 50 ML oxacillin 20 MG/MLRxCUI 31212850 ML oxacillin 40 MG/MLRxCUI 2406371000 MGRxCUI 17435472000 MGRxCUI 1743549 -
Dose form (SCDF) Oral Capsule RxCUI 373165No current FDA listingClinical drug / strength (SCD) 250 MGRxCUI 198054500 MGRxCUI 198055 -
Dose form (SCDF) Oral Suspension RxCUI 393313No current FDA listingClinical drug / strength (SCD) 50 MG/MLRxCUI 312129
Look up RxCUI 7773 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Oxacillin Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Oxacillin Injection belongs to the Penicillin-class Antibacterial class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 9 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Baxter Healthcare Corporation is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.