Phexin (Cefalexin) is a first-generation cephalosporin antibiotic engineered to deliver potent, broad-spectrum bactericidal action against susceptible Gram-positive and some Gram-negative pathogens. Its mechanism of action involves inhibition of bacterial cell wall synthesis, leading to osmotic instability and cell lysis. Clinically trusted for its reliable pharmacokinetic profile, Phexin ensures high tissue penetration and consistent serum concentrations, making it a cornerstone in outpatient and inpatient antimicrobial regimens for a variety of community-acquired infections.

Features

• Active pharmaceutical ingredient: Cefalexin (as monohydrate)
• Available formulations: 250 mg and 500 mg capsules; 125 mg/5 mL and 250 mg/5 mL oral suspensions
• Pharmacologic class: First-generation cephalosporin antibiotic
• Administration: Oral
• Half-life: Approximately 0.5–1.2 hours in adults with normal renal function
• Excretion: Primarily renal (≥90% unchanged in urine within 8 hours)

Benefits

• Effectively eliminates a wide range of susceptible bacteria, reducing infection duration and severity.
• High oral bioavailability ensures predictable therapeutic drug levels with consistent dosing.
• Well-established safety profile suitable for both adult and pediatric populations (over 1 year old).
• Convenient dosing schedule supports patient adherence and treatment completion.
• Rapid onset of action helps alleviate symptoms and prevent complications.
• Cost-effective generic option with proven clinical equivalence to brand formulations.

Common use

Phexin is indicated for the treatment of bacterial infections caused by susceptible strains of microorganisms. Common uses include:

• Respiratory tract infections (e.g., pharyngitis, tonsillitis, bronchitis)
• Skin and soft tissue infections (e.g., cellulitis, impetigo, abscesses)
• Urinary tract infections (e.g., cystitis, pyelonephritis)
• Otitis media (middle ear infection)
• Bone infections (osteomyelitis) caused by susceptible Staphylococci

Dosage and direction

Dosage must be individualized based on the infection’s severity, pathogen susceptibility, and the patient’s renal function.

Adults:

• Typical dose: 250 mg to 500 mg orally every 6 hours.
• For severe infections: Up to 1 g every 6 hours may be required.
• Maximum daily dose: 4 g.

Children:

• Usual dose: 25–50 mg/kg/day divided into 2–4 doses.
• For otitis media: 75–100 mg/kg/day divided into 4 doses.
• Maximum pediatric dose should not exceed adult dosing.

Phexin may be taken with or without food; administration with food may minimize gastrointestinal upset. Complete the full prescribed course even if symptoms improve earlier to prevent resistance.

Precautions

• Use with caution in patients with a history of gastrointestinal disease, particularly colitis.
• Renal impairment requires dosage adjustment; monitor creatinine clearance.
• Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi.
• Perform culture and susceptibility testing to confirm pathogen sensitivity before initiating therapy where practicable.
• Not recommended for the treatment of meningitis due to inadequate cerebrospinal fluid penetration.

Contraindications

Phexin is contraindicated in patients with:

• Known hypersensitivity to cefalexin or any cephalosporin antibiotics.
• A history of severe immediate hypersensitivity reactions (e.g., anaphylaxis) to penicillins or other beta-lactam antibiotics due to cross-reactivity risk.

Possible side effect

Common adverse reactions (generally mild and self-limiting) may include:

• Gastrointestinal: Diarrhea, nausea, vomiting, abdominal pain, dyspepsia
• Dermatological: Rash, urticaria, pruritus
• Other: Headache, fatigue, dizziness, genital pruritus or vaginitis

Serious side effects (require immediate medical attention):

• Severe diarrhea or bloody stools (may indicate Clostridium difficile-associated diarrhea)
• Signs of allergic reaction: swelling, difficulty breathing, severe skin reactions
• Unusual bleeding or bruising
• Severe skin reactions (e.g., Stevens-Johnson syndrome)
• Hepatotoxicity (jaundice, dark urine)

Drug interaction

• Probenecid: May decrease renal tubular secretion of cefalexin, increasing serum concentrations.
• Oral anticoagulants (e.g., warfarin): Potential enhancement of anticoagulant effect; monitor INR.
• Metformin: Cefalexin may increase metformin exposure; monitor blood glucose.
• Other nephrotoxic drugs (e.g., aminoglycosides, loop diuretics): Increased risk of renal dysfunction.

Missed dose

If a dose is missed, take it as soon as remembered. If it is almost time for the next dose, skip the missed dose and resume the regular schedule. Do not double the dose to catch up.

Overdose

Symptoms of overdose may include nausea, vomiting, epigastric distress, diarrhea, and hematuria. Management is supportive; gastric lavage may be considered if ingestion was recent. Hemodialysis can enhance elimination of cefalexin.

Storage

• Store at room temperature (15–30°C).
• Keep in the original container, tightly closed, and protect from moisture.
• Oral suspension: Refrigerate after reconstitution; discard unused portion after 14 days.
• Keep out of reach of children and pets.

Disclaimer

This information is intended for educational and professional reference only and does not replace medical advice. Always consult a qualified healthcare provider for diagnosis, treatment decisions, and personalized dosage recommendations. The prescriber should review official prescribing information for complete details.

Reviews

Phexin is widely regarded in clinical practice for its efficacy and tolerability. Healthcare professionals frequently note its reliability in treating common community-acquired infections, particularly those caused by Staphylococci and Streptococci. Patient feedback often highlights symptom improvement within 48–72 hours of initiation. Minor gastrointestinal disturbances are the most commonly reported drawback, though these are typically manageable. Overall, it remains a first-line option in many empirical treatment protocols.