Keflex

Common Uses

Keflex is prescribed to treat infections caused by susceptible bacteria. It belongs to a class of drugs known as cephalosporin antibiotics, which work by stopping the growth of bacteria. Common conditions treated with this medication include:

• Respiratory tract infections: This includes conditions such as pneumonia and tonsillitis.
• Skin and skin structure infections: It is used for various bacterial infections of the skin and the tissues just beneath it.
• Otitis media: This is a bacterial infection of the middle ear.
• Bone infections: Keflex may be used to treat infections that affect the skeletal system.
• Genitourinary tract infections: This includes acute infections of the bladder (cystitis) and the prostate.

Limitations of Use

Keflex is only effective against bacterial infections. It will not work for viral infections, such as the common cold, the flu, or most cases of bronchitis. Using an antibiotic when it is not needed increases the risk of developing an infection later that resists antibiotic treatment.

Healthcare providers typically determine if Keflex is appropriate by identifying the bacteria causing the infection through clinical assessment or laboratory testing. It is important to use the medication exactly as directed by a healthcare professional to ensure the infection is fully cleared.

Mechanism of Action

Keflex belongs to a class of medications known as cephalosporin antibiotics. It works by interfering with the way bacteria build their cell walls. These walls are essential for the bacteria to maintain their shape and protect themselves from the surrounding environment.

How It Kills Bacteria

When bacteria are growing and dividing, they must constantly repair and build new sections of their cell walls. Keflex binds to specific proteins within the bacterial cell that are responsible for constructing these walls. By blocking these proteins, the medication prevents the bacteria from creating a stable structure.

Without a strong cell wall, the pressure inside the bacterial cell becomes too great for the weakened exterior to handle. This causes the bacteria to rupture and die. Because Keflex actively kills the bacteria rather than just stopping their growth, it is considered a bactericidal antibiotic.

Targeting Specific Infections

Keflex is effective against a variety of bacteria, but it does not work for every type of infection. It is specifically designed to target bacterial processes and has no effect on viruses, such as those that cause the common cold or the flu.

Common Side Effects

• Nausea and vomiting
• Diarrhea
• Stomach pain or indigestion
• Dizziness or fatigue
• Headache
• Genital itching or discharge
• Joint pain

Serious Side Effects

Contact a healthcare provider immediately if you experience any of the following:

• Signs of an allergic reaction, such as hives, skin rash, or swelling of the face, lips, tongue, or throat.
• Severe stomach cramps and watery or bloody diarrhea, which may indicate a serious intestinal infection.
• Yellowing of the skin or eyes (jaundice) or dark-colored urine.
• Unusual bruising or bleeding.
• Fever, sore throat, and a painful red or purple rash that spreads and causes blistering or peeling.
• Confusion, hallucinations, or seizures.
• A significant decrease in the amount of urine passed.

Hypersensitivity Reactions

Serious and occasionally fatal hypersensitivity (allergic) reactions, including anaphylaxis, have been reported with the use of cephalosporins. Before starting Keflex, it is important to determine if there has been a previous reaction to cephalexin, other cephalosporins, or penicillins. There is a known risk of cross-sensitivity among beta-lactam antibiotics. If an allergic reaction occurs, the medication must be discontinued immediately.

Clostridioides difficile-Associated Diarrhea

Almost all antibacterial agents, including Keflex, can cause Clostridioides difficile-associated diarrhea (CDAD). This condition can range in severity from mild diarrhea to life-threatening inflammation of the colon. It occurs because the antibiotic alters the normal flora of the colon, allowing for the overgrowth of C. difficile. This may occur during treatment or more than two months after the antibiotic course has ended.

Kidney Impairment and Seizure Risk

In patients with significantly impaired kidney function, the dosage of Keflex may need to be adjusted based on creatinine clearance. High doses of cephalosporins administered to patients with renal impairment have been associated with the development of seizures. Careful clinical observation and laboratory monitoring are recommended for these individuals.

General Precautions

• Drug Resistance: Prescribing Keflex in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit and increases the risk of developing drug-resistant bacteria.
• Laboratory Test Interference: Use of this medication may cause a false-positive result on a Direct Coombs' test. It may also interfere with certain urine glucose tests that use copper reduction methods.
• Prolonged Use: As with other antibiotics, long-term use may result in the overgrowth of non-susceptible organisms, such as fungi, which may require additional treatment.

Pregnancy

Keflex is commonly used during pregnancy when a bacterial infection requires treatment. Research in animals has not shown evidence of harm to the developing fetus. However, there are no adequate and well-controlled studies in pregnant women. Because animal studies do not always predict how a human will respond, this medication should be used during pregnancy only if the potential benefits justify the potential risks.

Breastfeeding

Cephalexin, the active ingredient in Keflex, passes into breast milk in small amounts. It is generally considered compatible with breastfeeding. However, healthcare providers recommend monitoring the nursing infant for signs of sensitivity or changes in gut flora, which may include:

• Diarrhea
• Diaper rash
• Oral thrush (yeast infection)

If you are pregnant, planning to become pregnant, or breastfeeding, consult your doctor to discuss the safety and necessity of using this antibiotic.

Available Forms

Keflex is available for oral administration in the following form:

• Capsules

The active ingredient in Keflex, cephalexin, is also available in other generic oral formats, including:

• Tablets
• Oral suspension (a liquid form created from a powder)

FDA Approval Status

Keflex, the brand name for the drug cephalexin, is an FDA-approved medication. It belongs to the cephalosporin class of antibiotics and was first approved by the FDA in 1971. It is available only by prescription.

Approved Indications

The FDA has approved Keflex for the treatment of several types of infections caused by susceptible strains of bacteria. These include:

• Respiratory tract infections
• Otitis media (middle ear infections)
• Skin and skin structure infections
• Bone infections
• Genitourinary tract infections, including acute prostatitis

Regulatory Safety Information

Keflex does not currently have any FDA Boxed Warnings, which are the agency's most serious safety alerts. It is also not subject to a Risk Evaluation and Mitigation Strategy (REMS) program.

While the FDA has issued safety communications for other antibiotic classes, such as fluoroquinolones, regarding risks of aortic ruptures or tendon issues, these specific warnings do not apply to cephalosporins like Keflex. However, the FDA requires all systemic antibiotics to include warnings regarding the risk of Clostridioides difficile-associated diarrhea (CDAD) and the potential for developing drug-resistant bacteria if the medication is used inappropriately.

Alcohol and Keflex

There is no specific contraindication for consuming alcohol while taking Keflex (cephalexin). Unlike some other antibiotics, it does not cause a severe reaction when combined with alcohol. However, there are several reasons why you might choose to avoid alcohol during your treatment:

• Increased Side Effects: Alcohol can worsen common side effects of Keflex, such as nausea, dizziness, and stomach discomfort.
• Recovery Time: Alcohol can lead to dehydration and interfere with restful sleep, both of which are necessary for your immune system to effectively fight an infection.
• Symptom Masking: Drinking alcohol may make it more difficult to monitor your symptoms and determine if the antibiotic is working or if you are experiencing a reaction to the medication.

Always follow the specific advice of your healthcare provider regarding alcohol consumption while you are ill or taking prescription medications.