Cephalexin is a first-generation cephalosporin antibiotic prescribed to combat a wide range of bacterial infections. It operates by inhibiting bacterial cell wall synthesis, leading to the eradication of susceptible pathogens. This medication is commonly utilized for skin, respiratory, urinary tract, and bone infections due to its reliable efficacy and favorable safety profile. Proper usage as directed by a healthcare provider is essential to ensure optimal therapeutic outcomes and minimize the risk of antibiotic resistance.

Features

• Belongs to the cephalosporin class of antibiotics
• Available in capsule, tablet, and oral suspension formulations
• Typically dosed two to four times daily, depending on infection severity
• Requires a prescription; not available over-the-counter
• Effective against Gram-positive and some Gram-negative bacteria
• Generic versions are widely available, offering cost-effective treatment

Benefits

• Rapid onset of action to alleviate infection symptoms quickly
• High efficacy in treating common community-acquired infections
• Well-tolerated profile with a low incidence of severe adverse effects
• Flexible dosing forms suitable for both adults and pediatric patients
• Helps prevent complications from bacterial infections, such as sepsis or abscess formation
• Contributes to shorter illness duration and faster return to daily activities

Common use

Cephalexin is indicated for the treatment of infections caused by susceptible strains of microorganisms. Common uses include skin and soft tissue infections such as cellulitis and impetigo; respiratory tract infections including pharyngitis, tonsillitis, and bronchitis; otitis media (middle ear infection); bone and joint infections; genitourinary tract infections such as cystitis and prostatitis; and dental infections. It is also used as surgical prophylaxis in certain procedures to prevent postoperative infections. Diagnosis should be confirmed via culture and susceptibility testing where appropriate to ensure targeted therapy.

Dosage and direction

Dosage of cephalexin must be individualized based on the infection site, severity, and the patient’s renal function. For adults, the usual dose ranges from 250 mg to 1000 mg every 6 to 12 hours. For mild to moderate infections, 250 mg every 6 hours or 500 mg every 12 hours is typical. More severe infections may require 500 mg every 6 hours or 1000 mg every 12 hours. The maximum daily dose for adults is 4 grams. For pediatric patients, the recommended dosage is 25 to 100 mg/kg/day in divided doses, depending on the infection severity and pathogen. In children, the total daily dose should not exceed 4 grams. Oral suspension should be shaken well before each use. Cephalexin may be taken with or without food; taking with food may help reduce gastrointestinal upset. Complete the full prescribed course even if symptoms improve earlier to prevent recurrence and resistance.

Precautions

Before using cephalexin, inform your healthcare provider of any history of allergic reactions to cephalosporins, penicillins, or other drugs. Use with caution in patients with renal impairment; dosage adjustment may be necessary. Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi or bacteria, leading to secondary infections. If diarrhea occurs during or after treatment, it could indicate Clostridium difficile-associated diarrhea, which may range from mild to life-threatening. Avoid unnecessary use to reduce the risk of antibiotic-resistant bacteria. Use in pregnancy only if clearly needed and after discussing potential risks and benefits with a healthcare provider. Cephalexin is excreted in breast milk; caution is advised when administering to nursing mothers.

Contraindications

Cephalexin is contraindicated in patients with a known hypersensitivity to cephalexin or any component of the formulation. It is also contraindicated in those with a history of severe allergic reactions (e.g., anaphylaxis) to other cephalosporins. Cross-hypersensitivity among beta-lactam antibiotics may occur; patients with a history of penicillin allergy may be at increased risk. Do not use in patients with prior episodes of antibiotic-associated colitis or Clostridium difficile infection unless no other alternatives are available and benefits outweigh risks.

Possible side effect

Common side effects include gastrointestinal disturbances such as diarrhea, nausea, vomiting, abdominal pain, and dyspepsia. Other frequent reactions are dizziness, fatigue, headache, and genital pruritus or vaginitis. Skin reactions like rash, urticaria, and pruritus may occur. Less common side effects include reversible interstitial nephritis, hepatitis, eosinophilia, and neutropenia. Severe but rare adverse effects include anaphylaxis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and Clostridium difficile-associated diarrhea. If any severe or persistent side effects occur, discontinue use and seek medical attention promptly.

Drug interaction

Cephalexin may interact with several medications. Concomitant use with probenecid may reduce renal excretion of cephalexin, increasing its blood levels and risk of toxicity. Using with metformin can increase metformin concentrations, potentially enhancing its effects and side effects. Concurrent administration with oral anticoagulants like warfarin may potentiate anticoagulant effects, increasing the risk of bleeding; monitor coagulation parameters closely. Cephalexin may cause false-positive reactions in urine glucose tests when using cupric sulfate solution (Benedict’s solution, Clinitest®); use glucose oxidase methods (Clinistix®) instead. Avoid concurrent use with other nephrotoxic drugs, such as aminoglycosides or loop diuretics, to reduce the risk of renal impairment.

Missed dose

If a dose of cephalexin is missed, take it as soon as remembered. However, if it is almost time for the next scheduled dose, skip the missed dose and resume the regular dosing schedule. Do not double the dose to catch up. Maintaining consistent antibiotic levels is important for efficacy, so try to adhere to the prescribed interval as closely as possible. If multiple doses are missed or uncertainty exists about how to proceed, consult a healthcare provider or pharmacist for guidance.

Overdose

Overdose of cephalexin may manifest as nausea, vomiting, epigastric distress, diarrhea, and hematuria. In cases of significant overdose, especially in patients with renal impairment, neurotoxic reactions such as seizures may occur. Management is primarily supportive and symptomatic. Gastric lavage or administration of activated charcoal may be considered if ingestion was recent. Hemodialysis may aid in removing cephalexin from the bloodstream, particularly in patients with compromised renal function. If overdose is suspected, contact a poison control center or seek emergency medical attention immediately.

Storage

Store cephalexin capsules and tablets at room temperature, between 20°C to 25°C (68°F to 77°F), in a tightly closed container. Protect from light, moisture, and excessive heat. Keep the oral suspension refrigerated between 2°C to 8°C (36°F to 46°F) after reconstitution; discard any unused portion after 14 days. Do not freeze. Keep all medications out of reach of children and pets. Do not use beyond the expiration date printed on the packaging.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Do not disregard professional medical advice or delay in seeking it because of something you have read here. The content provided is based on general medical knowledge and may not reflect the most current research or specific product information.

Reviews

Clinical studies and patient reports consistently affirm cephalexin’s efficacy in treating susceptible bacterial infections, with many users noting rapid symptom improvement. Healthcare professionals appreciate its reliability and broad spectrum of activity, though emphasis is placed on appropriate use to curb resistance. Some users report mild gastrointestinal side effects, which are generally manageable. Overall, it remains a cornerstone in outpatient antibiotic therapy due to its proven track record and accessibility.