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nafcillin

Generic Name: nafcillin (injection) (naf SIL in)
Brand Names: Nallpen, Unipen

What is nafcillin?

Nafcillin is an antibiotic in the penicillin group of drugs. It fights bacteria in your body.

Nafcillin is used to treat many different types of infections, especially those caused by staphylococcus bacteria ("staph" infections).

Nafcillin may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about nafcillin?

Do not use this medication if you are allergic to nafcillin or to any other penicillin antibiotic, such as amoxicillin (Amoxil), ampicillin (Omnipen, Principen), oxacillin (Bactocill), penicillin (Beepen-VK, Ledercillin VK, Pen-V, Pen-Vee K, Pfizerpen, V-Cillin K, Veetids), and others.

Before using nafcillin, tell your doctor if you are allergic to cephalosporins such as Ceclor, Ceftin, Duricef, Keflex, and others, or if you have asthma, liver or kidney disease, or a history of any type of allergy.

Use this medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Nafcillin will not treat a viral infection such as the common cold or flu.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

What should I discuss with my healthcare provider before using nafcillin?

Do not use this medication if you are allergic to nafcillin or to any other penicillin antibiotic, such as:

amoxicillin (Amoxil, Amoxicot, Biomox, Dispermox, Trimox);
ampicillin (Omnipen, Principen);
carbenicillin (Geocillin);
cloxacillin (Cloxapen);
dicloxacillin (Dycill, Dynapen);
oxacillin (Bactocill); or
penicillin (Beepen-VK, Ledercillin VK, Pen-V, Pen-Vee K, Pfizerpen, V-Cillin K, Veetids, and others).

Before using nafcillin, tell your doctor if you are allergic to any drugs (especially cephalosporins such as Ceclor, Ceftin, Duricef, Keflex, and others), or if you have:

asthma;
liver disease;
kidney disease; or
a history of any type of allergy.

If you have any of these conditions, you may need a dosage adjustment or special tests during treatment.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Nafcillin can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I use nafcillin?

Use this medication exactly as it was prescribed for you. Do not use the medication in larger amounts, or use it for longer than recommended by your doctor. Follow the directions on your prescription label.

To be sure this medication is helping your condition, your blood will need to be tested on a regular basis. Your kidney or liver function may also need to be tested. Do not miss any scheduled visits to your doctor.

What happens if I miss a dose?

Use the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and use the medicine at your next regularly scheduled time. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include muscle spasms or weakness, muscle pain or twitching, numbness or tingly feeling, confusion, feeling light-headed, fainting, and seizure (black-out or convulsions).

What should I avoid while using nafcillin?

Avoid drinking alcohol. It can increase stomach irritation caused by nafcillin.

Nafcillin side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. A delayed allergic reaction to nafcillin can occur as few as 2 days to as many as 4 weeks after you use the medication. Call your doctor at once if you have any of these serious side effects:

feeling light-headed, fainting;
fever, weakness, muscle or joint pain, stomach pain;
diarrhea that is watery or bloody;
feeling short of breath;
urinating more or less than usual;
swelling, rapid weight gain; or
severe skin rash, itching, or peeling.

Less serious side effects are more likely to occur, such as:

pain, swelling, or skin changes where the medicine was injected;
nausea, vomiting, diarrhea, black or "hairy" tongue;
vaginal itching or discharge;
headache; or
thrush (white patches or inside your mouth or throat).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Nafcillin Dosing Information

Usual Adult Dose for Bacteremia:

2 g IV every 4 hours for 14 days depending on the nature and severity of the infection

Usual Adult Dose for Endocarditis:

Native valve endocarditis due to staphylococci: Nafcillin 2 g IV every 4 hours or 3 g IV every 6 hours (total 12 g/day) with or without gentamicin 3 mg/kg/day in 2 or 3 divided doses
Duration: Nafcillin, 6 weeks; gentamicin 3 to 5 days

Prosthetic valve endocarditis due to staphylococci: Nafcillin 2 g IV every 4 hours or 3 g IV every 6 hours (total 12 g/day) plus rifampin 300 mg orally every 8 hours, with or without gentamicin 3 mg/kg/day in 2 or 3 divided doses
Duration: Nafcillin and rifampin, 6 weeks or more; gentamicin 2 weeks

Refer to current published guidelines for detailed recommendations.

Usual Adult Dose for Joint Infection:

2 g IV every 4 hours for 3 to 4 weeks, depending on the nature and severity of the infection
Longer therapy, for 6 weeks or more, may be required for prosthetic joint infections.

Usual Adult Dose for Meningitis:

2 g IV every 4 hours for 14 days

Usual Adult Dose for Osteomyelitis:

2 g IV every 4 hours for 4 to 6 weeks, depending on the nature and severity of the infection
Chronic osteomyelitis may require additional oral antibiotic therapy, possibly for up to 6 months.

Usual Adult Dose for Pneumonia:

2 g IV every 4 hours
Therapy should continue for up to 21 days depending on the nature and severity of the infection.

Usual Adult Dose for Skin or Soft Tissue Infection:

1 to 2 g IV every 4 to 6 hours for 7 days, or for 3 days after acute inflammation resolves, depending on the nature and severity of the infection
More severe infections, such as diabetic soft tissue infections, may require 14 to 21 days of therapy.

Usual Pediatric Dose for Pharyngitis:

The safety and efficacy of nafcillin when administered IV in neonates and children have not been established. However, the use of nafcillin IV may be appropriate in some situations.

0 to 4 weeks, birthweight 1199 g or less: 25 mg/kg IV or IM every 12 hours

7 days or less:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 12 hours
birthweight 2001 g or more: 25 mg/kg IV or IM every 8 hours

8 days up to 1 month:
birthweight 1200 to 2000 g: 25 mg/kg IV or IM every 8 hours
birthweight 2001 g or more: 25 to 35 mg/kg IV or IM every 6 hours

1 month to 18 years:
Mild to moderate infections: 12.5 to 25 mg/kg IV or IM every 6 hours
Severe infections: 100 to 200 mg/kg/day IV in equally divided doses every 4 to 6 hours

Maximum dose: 12 g/day

Usual Pediatric Dose for Pneumonia:

Usual Pediatric Dose for Bacterial Infection:

Usual Pediatric Dose for Skin and Structure Infection:

Usual Pediatric Dose for Endocarditis:

Native valve endocarditis due to staphylococci: 200 mg/kg/day IV in equally divided doses every 4 to 6 hours for 6 weeks

Prosthetic valve endocarditis due to staphylococci: 200 mg/kg/day IV in equally divided doses every 4 to 6 hours for 6 weeks or longer with rifampin and gentamicin for the first 2 weeks of therapy

Maximum dose: 12 g/day

Refer to current published guidelines for detailed recommendations.

What other drugs will affect nafcillin?

Before using nafcillin, tell your doctor if you are using any of the following drugs:

cyclosporine (Gengraf, Neoral, Sandimmune);
a blood thinner such as warfarin (Coumadin); or
a tetracycline antibiotic such as demeclocycline (Declomycin), doxycycline (Adoxa, Doryx, Oracea, Vibramycin), minocycline (Dynacin, Minocin, Solodyn, Vectrin), or tetracycline (Brodspec, Panmycin, Sumycin, Tetracap).

This list is not complete and there may be other drugs that can interact with nafcillin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?

Your pharmacist can provide more information about nafcillin.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.