Keflex, whose generic name is cephalexin, is an antibiotic commonly prescribed to treat a variety of bacterial infections. As a member of the cephalosporin class of antibiotics, keflex has been widely used for decades due to its effectiveness and broad spectrum of activity. This article provides an in-depth overview of keflex, including its uses, how it works, dosages, side effects, precautions, and more, to help patients and healthcare providers make informed decisions.
What Is Keflex (Cephalexin)?
Keflex is a brand-name medication that contains cephalexin, a first-generation cephalosporin antibiotic. It is designed to eliminate bacteria by interfering with their cell wall synthesis, ultimately leading to bacterial death. Keflex is available in various formulations, including capsules, tablets, and oral suspensions, making it suitable for both adults and children.
Mechanism of Action
The primary action of cephalexin involves inhibiting bacterial cell wall synthesis. Bacteria have a rigid cell wall made of peptidoglycan, which is essential for their structural integrity. Cephalexin binds to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, disrupting cross-linking of peptidoglycan chains. This results in weakened cell walls that rupture under osmotic pressure, causing bacterial cell lysis and death.
Common Uses and Indications
Cephalexin is effective against a variety of gram-positive and some gram-negative bacteria. It is commonly prescribed for:
- Respiratory tract infections (e.g., pneumonia, tonsillitis)
- Skin and soft tissue infections (e.g., impetigo, cellulitis, wound infections)
- Otitis media (middle ear infections)
- Bone infections
- Urinary tract infections (occasionally, depending on susceptibility)
- Preoperative prophylaxis for certain surgeries
Dosage and Administration
Typical Dosages
The dosage of cephalexin depends on the type and severity of infection, age, weight, and renal function. Common adult doses include:
- Capsules/Tablets: 250 mg every 6 hours or 500 mg every 12 hours.
- Suspension (for children): 25-50 mg/kg/day divided into doses every 6-8 hours.
Administration Tips
- Take keflex with a full glass of water.
- It can be taken with or without food; however, taking it with food may reduce stomach upset.
- Complete the full course of therapy even if symptoms improve, to prevent resistant bacteria.
- If a dose is missed, take it as soon as remembered; if close to the next dose, skip the missed dose—do not double up.
Potential Side Effects
Common Side Effects
Most individuals tolerate keflex well, but some may experience side effects such as:
- Gastrointestinal discomfort (nausea, vomiting, diarrhea)
- Skin rash or itching
- Headache
- Fatigue
Serious Side Effects and When to Seek Help
Though rare, serious reactions can occur and require immediate medical attention:
- Allergic reactions (difficulty breathing, swelling of face or throat, hives)
- Severe diarrhea or bloody stools, which could indicate Clostridioides difficile infection
- Jaundice (yellowing of skin or eyes)
- Signs of kidney issues (dark urine, swelling)
Precautions and Warnings
Before taking keflex, inform your healthcare provider if you:
- Have a known allergy to cephalosporins or penicillins
- Have a history of gastrointestinal conditions, particularly colitis
- Are pregnant or breastfeeding
- Have kidney disease or impaired renal function
- Are taking other medications that may interact (see below)
Drug Interactions
Cephalexin can interact with several drugs, potentially altering their effectiveness or increasing side effects. Notable interactions include:
- Probenecid: May increase cephalexin levels by reducing renal excretion.
- Aminoglycosides: Concurrent use may enhance nephrotoxicity.
- Oral anticoagulants (e.g., warfarin): Antibiotics may increase bleeding risk; monitor INR levels.
- Other nephrotoxic drugs or drugs affecting renal function.
Special Considerations
Use in Children
Keflex is often prescribed for children because of its palatable suspension form and safety profile when used appropriately. Dosing should be carefully calculated based on weight and age.
Pregnancy and Breastfeeding
Animal studies have not shown significant fetal harm, and cefalexin is generally considered safe during pregnancy. However, it should only be used if clearly needed and prescribed by a healthcare provider. It passes into breast milk; therefore, breastfeeding infants should be monitored for potential reactions.
Resistance and Stewardship
Overuse or misuse of keflex can lead to antibiotic resistance, reducing its effectiveness over time. It is crucial to use this medication only for bacterial infections confirmed or strongly suspected by a healthcare professional.
Storage Guidelines
Proper storage ensures medication efficacy:
- Store in a cool, dry place away from direct sunlight.
- If stored as a suspension, keep refrigerated and discard after the specified expiry date or after 14 days of preparation.
- Keep out of reach of children.
Summary of Key Points
Keflex (Cephalexin) is an effective antibiotic for treating various bacterial infections, especially skin, respiratory, and bone infections. It works by inhibiting bacterial cell wall synthesis, leading to bacterial death. Proper dosing, adherence to the full course, and awareness of potential keflex cephalexin side effects and drug interactions are essential for safe and effective treatment.
Conclusion
Understanding keflex is vital for patients prescribed this medication. While generally safe, it requires cautious use, particularly in individuals with allergies or underlying health conditions. Always follow your healthcare provider’s instructions, report any adverse effects promptly, and ensure completion of the prescribed course to effectively clear infections and prevent resistance development.