Cloxacillin belongs to the group of medications known as antibiotics, specifically to the family of antibiotics known as penicillins. Cloxacillin is used for the treatment of certain bacterial infections. It is most commonly used to treat infections of the skin, bone, heart valve, blood, and lung. Cloxacillin kills some types of bacteria that can cause these infections.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose of oral (taken by mouth) cloxacillin ranges from 250 mg to 500 mg 4 times daily taken on an empty stomach (1 hour before or 2 hours after meals). The children's and infant's doses depend on the age and weight of the child.

The injectable form of cloxacillin is used in the hospital. The dose depends on the person's weight and the type of infection. The dose of cloxacillin is injected into the vein or muscle every 6 hours.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Use an oral syringe to measure each dose of the liquid, as it gives a more accurate measurement than household teaspoons.

It is important to use this medication exactly as prescribed by your doctor. Finish all of this medication, even if you start to feel better. If you miss a dose, use it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not use a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Store the oral solution form of this medication in the refrigerator, and keep it out of the reach of children.

Do not take cloxacillin if you:

• are allergic to cloxacillin or any ingredients of the medication
• have a serious penicillin allergy

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea (mild)
• gas
• nausea
• upper abdominal pain or discomfort
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• diarrhea (watery and severe; may also be bloody)
• sore mouth or tongue
• yellow eyes or skin
• swollen, red, warm, or painful vein at injection site (for injectable form)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of an allergic reaction (e.g., swelling of the hands, feet, ankles, face, lips, mouth, or throat; difficulty breathing or swallowing)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergy: Cloxacillin is a type of penicillin and therefore should not be used by anyone with a serious penicillin allergy. People who have allergies in general should watch carefully for any reaction to cloxacillin when starting a new prescription.

Other infections: Treatment with any antibiotic may allow normal fungus or types of bacteria not killed by the antibiotic to overgrow, causing unwanted infections such as yeast infections. Contact your doctor as soon as possible if you notice symptoms of a new infection.

Stomach problems: People taking this medication may develop diarrhea caused by an infection with the bacteria C. difficile. If you have loose, watery and bloody bowel movements, with or without fever or stomach cramps after taking cloxacillin, get medical attention as soon as possible. Diarrhea caused by C. difficile infection can lead to serious health problems if it is not properly treated.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking cloxacillin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

There may be an interaction between cloxacillin and any of the following:

• aminoglycosides (e.g., gentamicin, tobramycin)
• birth control pills
• methotrexate
• tetracyclines (e.g., minocycline, doxycycline)
• typhoid vaccine
• warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.