• Basic Info
• Top Questions
• Interactions

What is cloxacillin?
Cloxacillin is an antibiotic in the class of drugs called penicillins. It fights bacteria in your body. Cloxacillin is used to treat many different types of infections caused by staphylococcus bacteria ("staph" infections). Cloxacillin may also be used for purposes other than those listed in this medication guide.

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What are the possible side effects of cloxacillin?

If you experience any of the following serious side effects, stop taking cloxacillin and seek emergency medical attention:

• an allergic reaction (shortness of breath; closing of your throat; hives; swelling of your lips, face, or tongue; rash; or fainting);

• seizures;

• severe watery diarrhea and abdominal cramps; or

• unusual bleeding or bruising.

Other, less serious side effects maybe more likely to occur. Continue to take cloxacillin and talk to your doctor if you experience

• mild nausea, vomiting, diarrhea, or abdominal pain;

• white patches on the tongue (thrush/yeast infection);

• itching or discharge of the vagina (vaginal yeast infection); or

• black, "hairy" tongue or sore mouth or tongue.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

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How should I take cloxacillin?
Take cloxacillin exactly as directed by your doctor. If you do not understand these instructions, ask your pharmacist, nurse, or doctor to explain them to you. Take each dose with a full glass of water. Take cloxacillin on an empty stomach 1 hour before or 2 hours after meals. Do not drink juice or carbonated beverages (soda) with your dose of cloxacillin. These beverages will decrease the effectiveness of the drug. Cloxacillin should be taken at evenly spaced intervals throughout the day and night to keep the level in your blood high enough to treat the infection.

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What is the most important information I should know about cloxacillin?
Take all of the cloxacillin that has been prescribed for you even if you begin to feel better. Your symptoms may begin to improve before the infection is completely treated. Do not break, chew, open, or crush the capsules. Swallow them whole. Cloxacillin may decrease the effectiveness of birth control pills. Use a second method of birth control while taking cloxacillin to protect against pregnancy.

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What happens if I miss a dose?
Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the dose you missed and take only your next regularly scheduled dose. Do not take a double dose of this medication unless otherwise directed by your doctor. If you have only missed one dose, you can take the rest of your scheduled doses for the day at evenly spaced intervals.

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What other drugs will affect cloxacillin?
Some drugs may decrease the effects of cloxacillin and prevent it from properly treating your infection. Before taking cloxacillin, tell your doctor if you are taking any of the following drugs: cholestyramine (Questran) or colestipol (Colestid); or another antibiotic (for the same or for a different infection) such as erythromycin (Ery-Tab, E-Mycin, E.E.S., others), tetracycline (Sumycin, others), minocycline (Minocin), doxycycline (Doryx, Vibramycin, others), or any other. Cloxacillin may decrease the effectiveness of birth control pills. Use a second method of birth control while taking cloxacillin to protect against pregnancy.

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Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Cloxacillin has been assigned to pregnancy category B. There are no controlled data in human pregnancies; however, there are no literature reports of congenital abnormalities associated with it. Cloxacillin should only be given during pregnancy when need has been clearly established.

There are no data on the excretion of cloxacillin into human milk. Other penicillins are excreted into human milk in small amounts. Adverse effects in the nursing infant are unlikely.

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What does my medication look like?
Cloxacillin is available generically and with a prescription in 250 and 500 mg capsules and in a suspension formulation of 120 mg per 5 mL (1 teaspoon). Other brand or generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.

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What happens if I overdose?
Seek emergency medical attention. Symptoms of an cloxacillin overdose include muscle spasms or weakness, pain or twitching, pain in the fingers or toes, loss of feeling in the fingers or toes, seizures, confusion, coma, and agitation.

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Who should not take cloxacillin?
If you have ever had an allergic reaction to another penicillin or to a cephalosporin, do not take cloxacillin unless your doctor is aware of your allergy and monitors your therapy. Before taking this medication, tell your doctor if you have kidney disease, stomach or intestinal disease, or infectious mononucleosis. You may not be able to take cloxacillin because of an increased risk of side effects. If you are a diabetic, some glucose urine tests may give false positive results while you are taking cloxacillin.

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Can I stop taking the medication if I feel better?
If you have been diagnosed with a disease for which an antibiotic is needed, you must complete the prescribed course of treatment. Even if you start to feel better, do not skip any doses and remember to take the medication until it is all gone.

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I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

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