How Cephalexin Works
Cephalexin is a first-generation cephalosporin antibiotic that belongs to the β-lactam family. It works by interfering with bacterial cell wall synthesis, ultimately causing bacterial cell death. This medication has been a cornerstone of antibiotic therapy since its introduction in the 1960s and is effective against both gram-positive and some gram-negative bacteria.
Common Uses
Cephalexin is primarily used to treat various bacterial infections, including:
Respiratory Tract Infections
- Pneumonia
- Bronchitis
- Strep throat
- Tonsillitis
Skin and Soft Tissue Infections
- Cellulitis
- Folliculitis
- Wound infections
- Impetigo
- Furuncles
Other Applications
- Urinary tract infections (UTIs)
- Bone and joint infections (osteomyelitis)
- Ear infections (otitis media)
- Dental infections
It is important to note that cephalexin is not effective against viral infections such as the common cold or flu.
Proper Dosage
The appropriate dosage varies depending on several factors:
Adults
- Mild to moderate infections: 250-500mg every 6 hours
- Severe infections: Up to 4g daily in divided doses
Children
The dose is usually calculated based on the child's weight, typically 25 to 50 mg/kg per day, divided into multiple doses.
Important: Always complete the full course of antibiotics as prescribed, even if symptoms improve before completion.
Side Effects
Common Side Effects
- Diarrhea
- Nausea
- Vomiting
- Stomach pain
- Headache
Serious Side Effects
These require immediate medical attention:
- Severe allergic reactions (rash, itching, swelling, severe dizziness, trouble breathing)
- Clostridioides difficile infection
- Severe skin reactions
- Signs of kidney problems (change in amount of urine)
- Persistent diarrhea
Special Populations
Pregnancy and Breastfeeding
Cephalexin is generally considered safe during pregnancy (Category B) and while breastfeeding. However, always consult your healthcare provider before use.
Elderly Patients
Older adults may need dose adjustments due to:
- Decreased kidney function
- Increased risk of side effects
- Potential drug interactions
Storage and Handling
Store cephalexin:
- At room temperature (20-25°C/68-77°F)
- Away from moisture and heat
- Out of reach of children
- In its original container
Precautions and Interactions
Before taking cephalexin, inform your doctor if you have:
- Allergies, particularly to penicillins or other cephalosporins
- Kidney disease
- History of gastrointestinal disease
- Other medications, especially probenecid or blood thinners
Antibiotic Resistance
To prevent antibiotic resistance:
- Only use antibiotics when prescribed
- Complete the full course
- Never share antibiotics
- Don't save leftover antibiotics
For more detailed information, you can visit resources like Drugs.com, the Mayo Clinic, or the FDA medication guide.