Keflex, whose generic name is cephalexin, is a widely prescribed antibiotic used to combat various bacterial infections. Belonging to the class of antibiotics known as cephalosporins, Keflex has proven effective against a broad spectrum of bacteria, making it a valuable medication in both outpatient and inpatient settings. This comprehensive guide provides detailed insights into Keflex, including its uses, mechanism of action, dosage, potential side effects, precautions, and more.
What is Keflex (Cephalexin)?
Keflex is an oral antibiotic primarily used to treat infections caused by susceptible bacteria. It was first introduced in the 1960s and has since become a staple in treating respiratory tract infections, skin infections, ear infections, and urinary tract infections, among others.
The active ingredient, cephalexin, belongs to the cephalosporin class of antibiotics. These drugs work by disrupting the synthesis of bacterial cell walls, leading to bacterial death. Unlike some antibiotics, Keflex is bactericidal, meaning it kills bacteria rather than merely inhibiting their growth.
Indications and Uses of Keflex
Primary Medical Conditions Treated
Keflex is indicated for a variety of bacterial infections, including:
- Skin and Soft Tissue Infections: Cellulitis, wound infections, abscesses, impetigo
- Respiratory Tract Infections: Pharyngitis, tonsillitis, otitis media, sinusitis
- Urinary Tract Infections (UTIs): Cystitis, pyelonephritis (as prescribed)
- Bone Infections: Osteomyelitis (in some cases)
- Throat Infections: Streptococcal pharyngitis
Off-Label and Other Uses
Although primarily approved for bacterial infections, healthcare providers may prescribe Keflex off-label for other microbial infections based on clinical judgment and bacterial susceptibility.
How Does Cephalexin Work?
The mechanism of cephalexin involves inhibiting bacterial cell wall synthesis. Specifically, it binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, preventing cross-linking of peptidoglycan chains. This disruption weakens the bacterial cell wall, causing it to rupture and leading to bacterial cell death.
This mode of action makes cephalexin effective mainly against actively dividing bacteria. It is most potent against Gram-positive bacteria, such as Staphylococcus aureus (including some methicillin-sensitive strains) and Streptococcus pneumoniae.
Dosage and Administration
Standard Dosage Regimen
The appropriate dosage of Keflex depends on the severity of the infection, patient age, weight, and kidney function. Typical adult dosing includes:
- For Mild to Moderate Infections: 250 mg to 500 mg every 6 to 12 hours
- For More Severe Infections: 750 mg to 1,000 mg every 12 hours (divided doses)
Children’s Dosing
- Typically ranges from 25 mg/kg/day divided into doses every 6 to 12 hours
- Adjustments may be necessary based on weight and infection severity
Duration of Treatment
The length of therapy varies depending on the infection type but generally lasts from 5 to 14 days. It is crucial to complete the full course of medication, even if symptoms improve before finishing the prescribed duration.
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
- Maintain consistent timing to keep drug levels stable in your bloodstream
- Do not skip doses or stop medication keflex cephalexin early unless instructed by your healthcare provider
Potential Side Effects of Keflex
Common Side Effects
- Nausea, vomiting, or diarrhea
- Stomach pain or indigestion
- Rash or mild skin reactions
- Dizziness or headache
Serious but Rare Side Effects
- Allergic reactions: Anaphylaxis, swelling of face/tongue/throat, difficulty breathing
- Clostridioides difficile infection: Persistent diarrhea with mucus or blood
- Hematologic issues: Leukopenia, thrombocytopenia, eosinophilia
- Liver damage: Elevated liver enzymes, hepatitis (rare)
Precautions and Warnings
Allergy Considerations
If you have a known allergy to cephalosporins or penicillin antibiotics, inform your healthcare provider before starting Keflex. Cross-reactivity can occur, increasing the risk of allergic reactions.
Kidney Function
Patients with impaired renal function should receive dose adjustments to prevent accumulation and toxicity. Regular monitoring of kidney function may be necessary during therapy.
Pregnancy and Breastfeeding
Cephalexin is generally considered safe during pregnancy and breastfeeding. However, consult your doctor before use to weigh potential benefits and risks.
Drug Interactions
Interactions with other medications are possible, including:
- Probenecid: May increase cephalexin levels
- Aminoglycosides: Potential additive nephrotoxicity
- Oral anticoagulants: Possible increased bleeding risk
Storage and Handling
Keep Keflex tablets or capsules in a tightly closed container at room temperature, away from moisture, light, and heat. If using liquid suspension, store it refrigerated and discard any unused portion after the expiration date or after 14 days of opening.
When to Seek Medical Attention
If you experience any signs of severe allergic reactions, persistent diarrhea, jaundice, or unusual bleeding, seek medical attention promptly. Additionally, if your symptoms do not improve within a few days of therapy, consult your healthcare provider.
Summary: Key Takeaways About Keflex (Cephalexin)
- Keflex is an effective oral antibiotic primarily used to treat bacterial infections such as skin, respiratory, and urinary tract infections.
- Cephalexin works by inhibiting bacterial cell wall synthesis, leading to bacterial death.
- Proper dosing, administration, and completing the full course are vital to ensure effectiveness and prevent resistance.
- While generally safe, Keflex can cause side effects ranging from mild gastrointestinal discomfort to severe allergic reactions.
- Individuals with allergies to cephalosporins or penicillins should avoid Keflex unless directed otherwise by a healthcare professional.
Final Advice
Always consult your healthcare provider for personalized medical advice, especially regarding dosage, duration of therapy, and potential interactions. Never self-medicate or alter your prescribed treatment plan without professional guidance. Responsible use of antibiotics like Keflex helps maintain their effectiveness and prevents the development of resistant bacterial strains.
