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Nafcillin (injection)

Generic Name: Nafcillin (injection) [naf-SIL-in].
Names of Brands: Unipen, Nallpen.
Dosage Forms: Injectable powder for injection (1 g; 10 g; 2 g); intravenous solution (1 g/50 mL; 2 g/100 mL).
Class of Drugs: Penicillinase-resistant penicillins.

What is Nafcillin?

Nafcillin is a penicillin antibiotic. It is used to treat a variety of kinds of infections, particularly ones caused by staphylococcus (staph) infections. Nafcillin can also be used for reasons not mentioned in this guide to medication.

Side effects of Nafcillin

Contact emergency medical assistance. If you notice symptoms that are warning signs of an allergic reaction, such as itching, hives, fever, and stomach pain, You may also experience muscle or joint discomfort, breathing difficulties, or swelling of your lips, tongue, throat, or face. An allergic reaction that is delayed by nafcillin could occur as little as two days or up to four weeks after the use of the drug. Nafcillin could cause serious adverse side effects. If you experience symptoms, consult with your physician immediately:

  • Discomfort, burning, or swelling surrounding the IV needle after the medication is injected.
  • Intense stomach pains; diarrhea that is bloody or watery (even when it happens several months after the most recent dose).
  • Minimal or no urination.
  • Bleeding or urine that is swollen.
  • Your body or lower back may feel restricted.
  • Bruises, swelling, pain, or changes to the skin where the medicine was injected.
  • Skin itching, joint pain, discomfort.
  • Fever, chills, swollen glands, sore throat, cough, difficulty breathing.
  • The appearance of blisters or ulcers on your mouth, swollen or red gums, or difficulty swallowing.

Common negative effects of nafcillin include:

  • Nausea, vomiting, diarrhea.
  • Itchy skin.
  • Tongues are black tongues, "hairy" tongues.
  • Itching, irritation, or irritation around the injection needle.

This is not a comprehensive list of all the side effects. Others could happen. Contact your doctor for advice regarding medical effects. You can report any symptoms to the FDA at 1-800-FDA-1088.


It is not recommended to use nafcillin if you have an allergy to penicillin or any other antibiotic.

Beforeyou take this drug.

It is not recommended to take this medicine if your body is allergic to nafcillin and similar antibiotics like:

  • Amoxicillin (Amoxil, Augmentin, and many others).
  • Ampicillin.
  • Dicloxacillin.
  • Oxacillin.
  • Penicillin.

Inform your physician immediately if you experience symptoms related to allergy:

  • Asthma.
  • Allergies.
  • The liver condition.
  • Kidney disease kidney disease.
  • Any kind of allergic reaction (especially an allergy to antibiotics).

No one knows if this medication will have an impact on newborn babies. Inform your doctor if you are pregnant or planning to be pregnant. Nafcillin may be absorbed into the breast milk and cause harm to the nursing infant. Inform your doctor if you are nursing the baby.

How to take Nafcillin?

Follow the directions on your prescription label and go through all medication guides or instruction sheets. Make sure you use the medication exactly as prescribed. Nafcillin is administered as an infusion into veins or injected into muscles. The healthcare professional will provide the first dose and guide you on how to utilize the drug on your own. The process of infusion into a vein could take between 30 and 60 minutes to be completed.

Take note of and follow the instructions for use that come with your medication. Consult your physician or pharmacist for clarification if you aren't sure about the instructions. Nafcillin powder needs to be mixed with the aid of a liquid (diluent) prior to use. If you inject muscles, administer the injection immediately after mixing the powder with the diluting agent. If you inject it into a vein, you can keep the mixture at room temperature for up to 3 days or in the refrigerator for up to 7 days. Avoid using the mixture if it changes color or has particles. Consult your pharmacist about the latest information on the medicine. Keep unmixed nafcillin powder at room temperature, away from heat and moisture. The medicine could be available in a premixed solution that is stored in a plastic container. Storage: Store frozen Nafcillin in an extremely deep freezer at -4° Fahrenheit (-20° Celsius).

Remove the medicine from the freezer and allow it to get to room temperature before putting in the dose. It is also possible to thaw the medicine in the fridge. Don't use heating to melt the frozen Nafcillin. Utilize nafcillin for the entire prescribed time period, regardless of whether your symptoms improve quickly. Inadequate doses could increase your chances of getting an illness that is intolerant to treatment. Nafcillin is not a treatment for a virus like influenza or the typical cold. Make use of a needle and syringe just once, and then put them in the puncture-proof "sharps" container. Make sure you follow local or state laws on how to dispose of the container. keep it out of reach of children.

What happens if I miss a dose?

Utilize the medication as soon as you are able, but do not miss your missed dose if it's nearing the time to take the next dose. Do not take two doses at the same time.

What happens if I overdose?

For medical emergencies, seek emergency medical attention or contact the Poison Help line at 1-800-222-1222. The symptoms of an overdose can include anxiety or confusion, hand tremors, hallucinations, seizures, coma, or even agitation.

What should be avoided?

The use of antibiotics can trigger diarrhea, which could be a sign of a new infection. If you are experiencing diarrhea that is bloody or watery and you are unsure of the cause, consult your doctor prior to applying anti-diarrhea medications.

Interaction with other drugs

Inform your physician of any other medications you are taking, particularly over-the-counter remedies:

  • Cyclosporine.
  • Warfarin (Coumadin, Jantoven).
  • A tetracycline antibiotic—doxycycline, minocycline, or tetracycline.

This list isn't exhaustive. Other medications may interact with the nafcillin receptor, including medications that are prescribed and available over the counter, vitamins, and herbal supplements. There are many possible interactions between drugs, which are listed here.