This medication is a cephalosporin-type antibiotic used to treat a wide variety of bacterial infections (e.g., skin, bone and genitourinary tract infections). Cephalexin is used to treat many different types of bacterial infections such as bronchitis, tonsillitis, ear infections, skin infections, and urinary tract infections.
How to use
Take this medication by mouth usually every 6 or 12 hours, or as directed by your doctor. You may take this medicine with food if stomach upset occurs. Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. Continue to take this medication until the full-prescribed amount is finished even if symptoms disappear after a few days. Stopping this medication too early may allow bacteria to continue to grow, which may result in a relapse of the infection. Inform your doctor if your condition persists or worsens.
Drug Class and Mechanism
Cephalexin belongs to a class of antibiotics, called cephalosporins. They are similar to penicillin in action and side effects. They stop or slow the growth of bacterial cells by preventing bacteria from forming the cell wall that surrounds each cell. The cell wall protects bacteria from the external environment and keeps the contents of the cell together. Without a cell wall, bacteria are not able to survive. Bacteria that are susceptible to cephalexin include Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, E. coli and several others.
Take the missed dose as soon as you remember, then try to evenly space the rest of the doses for that day until you can return to a normal schedule. Do not take a double dose of this medication unless otherwise directed by your doctor.
Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.
Before taking cephalexin, tell your doctor or pharmacist if you are allergic to it; or to penicillins or other cephalosporins; or if you have any other allergies. Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, intestinal disease (colitis). This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This medication passes into breast milk. Consult your doctor before breast-feeding.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: live vaccines, probenecid. This medication may decrease the effectiveness of combination-type birth control pills. This can result in pregnancy. You may need to use an additional form of reliable birth control while using this medication. Consult your doctor or pharmacist for details. This medication may cause false positive results with certain diabetic urine testing products (cupric sulfate-type). This drug may also affect the results of certain lab tests. Make sure laboratory personnel and your doctors know you use this drug. Do not start or stop any medicine without doctor or pharmacist approval.
Possible Side Effects
Stomach upset, headache, fatigue, dizziness, or diarrhea may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes. Tell your doctor immediately if any of these highly unlikely but very serious side effects occur: stomach/abdominal pain, persistent nausea/vomiting, yellowing eyes or skin, dark urine, new signs of infection (e.g., persistent sore throat or fever), easy bruising/bleeding, change in the amount of urine. This medication may rarely cause a severe intestinal condition (pseudomembranous colitis) due to a resistant bacteria. This condition may occur while receiving therapy or even weeks after treatment has stopped. Do not use anti-diarrhea products or narcotic pain medications if you have the following symptoms because such products may make them worse. Tell your doctor immediately if you develop persistent diarrhea, abdominal or stomach pain/cramping, or blood/mucus in your stool. Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (oral or vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge or other new symptoms. A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching, swelling, severe dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.
If you experience any of the following serious side effects, stop taking cephalexin and seek emergency medical attention or contact your doctor immediately:
an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, face, or tongue; hives; or a rash);
rash, redness, or itching;
severe nausea, vomiting, or diarrhea;
mucous or blood in the stool; or
unusual bleeding or bruising.
Other, less serious side effects may be more likely to occur. Continue to take cephalexin and talk to your doctor if you experience
mild nausea or diarrhea, or
a yeast infection of the mouth or vagina.
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.