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.
The generic name is Cloxacillin (klox a sill in). Brand names are Cloxapen, Tegopen.
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.
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 diabetic, some glucose urine tests may give false positive results while you are taking cloxacillin.
Cloxacillin is in the FDA pregnancy category B. This means that it is unlikely to harm an unborn baby. Do not, however, take cloxacillin without first talking to your doctor if you are pregnant. It is not known whether cloxacillin passes into breast milk. Do not take this medication without first talking to your doctor if you are breast-feeding a baby.
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.
Do not crush, chew, or open the capsules. Swallow them whole. Shake the suspension well before measuring a dose. To ensure that you get a correct dose, measure the liquid form of cloxacillin with a dose-measuring spoon or cup, not a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one. Take all of the cloxacillin that has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated. Store the capsules at room temperature and store the suspension in the refrigerator for longer use. The suspension is good for 14 days if it is stored in the refrigerator. Throw away any unused liquid after this amount of time.
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.
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.
What should I avoid while taking cloxacillin?
Alcohol may irritate your stomach if taken with cloxacillin, so use it with moderation.
Cloxacillin side effects
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);
- severe watery diarrhea and abdominal cramps; or
- unusual bleeding or bruising.
Other, less serious side effects may be more likely to occur. Continue to take cloxacillin and talk to your doctor if you experience any symptoms.
- 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.
Other side effects other than those listed here may also occur. Talk to your doctor about any side effects that seem unusual or that are especially bothersome.
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.
Cloxacillin increases the effects of methotrexate, and you may need a dose adjustment during therapy with cloxacillin.
Cloxacillin also increases the side effects of allopurinol (Zyloprim) and may cause a rash.
Probenecid (Benemid) increases the effects of cloxacillin. These drugs may be used together for this purpose. However, be sure your doctor is aware if you are taking probenecid. You may need a lower dose of cloxacillin.
Drugs other than those listed here may also interact with cloxacillin. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicine.
Where can I get more information?
Your pharmacist has additional information about cloxacillin written for health professionals that you may read.
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.