Phexin is a branded pharmaceutical preparation containing the active substance Cefalexin, a first-generation cephalosporin antibiotic. It is indicated for the treatment of a wide spectrum of bacterial infections caused by susceptible strains of microorganisms. This bactericidal agent works by inhibiting the synthesis of the bacterial cell wall, leading to the effective elimination of pathogenic bacteria. Phexin is a critical tool in the clinician’s arsenal for managing community-acquired infections across various organ systems, offering a reliable and well-established therapeutic profile.

Features

• Active Ingredient: Cefalexin (as Cefalexin Monohydrate)
• Drug Class: First-generation cephalosporin antibiotic
• Available Formulations: 250 mg and 500 mg capsules; 125 mg/5 mL and 250 mg/5 mL powder for oral suspension
• Pharmacological Action: Bactericidal; inhibits bacterial cell wall synthesis
• Spectrum of Activity: Effective against Gram-positive bacteria including Staphylococcus aureus (non-MRSA), Streptococcus pneumoniae, Streptococcus pyogenes; some Gram-negative bacteria including Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae
• Bioavailability: Well-absorbed from the gastrointestinal tract, with peak serum concentrations occurring within one hour
• Administration: Oral

Benefits

• Provides rapid and potent bactericidal action against a broad range of common pathogenic bacteria, facilitating swift clinical improvement.
• High oral bioavailability ensures effective systemic concentrations, making it suitable for outpatient management of infections.
• Well-established safety and efficacy profile, backed by decades of clinical use and extensive post-marketing surveillance data.
• Flexible dosing regimens and multiple formulations (capsules and suspension) allow for tailored treatment across different age groups and patient preferences.
• Cost-effective therapeutic option compared to newer broad-spectrum antibiotics, supporting rational antimicrobial stewardship.
• Effective in treating recurrent infections, particularly those of the respiratory and urinary tracts, reducing the likelihood of complications.

Common use

Phexin (Cefalexin) is commonly prescribed for the treatment of bacterial infections where the causative organisms are known or suspected to be susceptible to its action. Its primary indications include infections of the respiratory tract such as pharyngitis, tonsillitis, and acute bronchitis caused by susceptible Streptococcus species. It is highly effective in managing skin and soft tissue infections, including cellulitis, impetigo, and wound infections, particularly those attributable to Staphylococcus aureus. In genitourinary medicine, it is utilized for uncomplicated urinary tract infections caused by susceptible strains of E. coli, Proteus mirabilis, and Klebsiella species. Off-label uses, under specialist supervision, may include dental prophylaxis in high-risk patients and adjunctive treatment in orthopedic infections involving susceptible organisms.

Dosage and direction

Dosage must be individualized based on the infection’s severity, the causative organism’s susceptibility, and the patient’s renal function. For adults, the typical dosage for mild to moderate infections is 250 mg to 500 mg orally every 6 hours. For more severe infections, doses of 500 mg to 1 gram every 6-8 hours may be required. The maximum daily dose for adults should not exceed 4 grams. For pediatric patients, the recommended dosage is 25 to 50 mg/kg/day divided into four equal doses. For more severe infections, the dose may be increased to 75 to 100 mg/kg/day, not to exceed 4 grams per day. The oral suspension should be shaken well before each administration. Phexin can be taken with or without food; however, administration with food may minimize potential gastrointestinal discomfort. The full prescribed course must be completed, even if symptoms improve, to prevent the development of antibiotic resistance.

Precautions

Prior to initiating therapy with Phexin, a careful history should be taken concerning previous hypersensitivity reactions to cephalosporins, penicillins, or other beta-lactam antibiotics due to the risk of cross-reactivity. Use with caution in patients with a history of gastrointestinal disease, particularly colitis, as antibiotic use can predispose to Clostridium difficile-associated diarrhea. Renal function should be assessed, especially in the elderly or those with pre-existing renal impairment, as dosage adjustments are necessary to prevent accumulation and potential toxicity. Prolonged use may result in the overgrowth of non-susceptible organisms, including fungi; if superinfection occurs during therapy, appropriate measures should be instituted. As with all antibiotics, Phexin should only be used to treat bacterial infections and is ineffective against viral illnesses like the common cold or influenza.

Contraindications

Phexin is contraindicated in patients with a known history of serious hypersensitivity reactions (e.g., anaphylaxis, Stevens-Johnson syndrome) to Cefalexin, any other cephalosporin antibiotic, or any component of the formulation. It is also contraindicated in patients with a history of severe immediate hypersensitivity reactions to penicillins or other beta-lactam antibiotics due to the potential for cross-sensitivity, which occurs in approximately 3-7% of penicillin-allergic patients.

Possible side effect

As with all pharmacological agents, Phexin may cause adverse effects. The most commonly reported side effects are gastrointestinal in nature and include diarrhea (which can range from mild to severe), nausea, vomiting, abdominal pain, and dyspepsia. Skin reactions such as rash, urticaria, and pruritus may occur. Less frequently, patients may experience dizziness, fatigue, headache, or reversible interstitial nephritis. Vaginal candidiasis or oral thrush may develop due to alteration of normal flora. As with nearly all broad-spectrum antibiotics, there is a risk of Clostridium difficile-associated diarrhea (CDAD), which may range in severity from mild diarrhea to fatal colitis. Any patient who develops diarrhea during or after antibiotic treatment should be evaluated for this condition. Serious but rare adverse effects include hepatotoxicity, blood dyscrasias (e.g., neutropenia, thrombocytopenia), and severe hypersensitivity reactions.

Drug interaction

Concurrent administration of Phexin with potent diuretics such as furosemide or ethacrynic acid may increase the potential for nephrotoxicity and should be avoided unless the benefits outweigh the risks. Probenecid competitively inhibits the renal tubular secretion of cephalosporins, leading to increased and prolonged blood levels of Cefalexin. Concomitant use with bacteriostatic antibiotics (e.g., tetracyclines, erythromycin) may antagonize the bactericidal effect of Phexin. The administration of Cefalexin may result in a false-positive reaction for glucose in the urine when using Benedict’s or Fehling’s solution or with Clinitest® tablets; glucose tests based on enzymatic glucose oxidase reactions (e.g., Clinistix®) are recommended. It may also cause a false-positive direct Coombs test.

Missed dose

If a dose of Phexin is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped, and the regular dosing schedule resumed. Patients should be advised not to double the dose to make up for a missed one, as this increases the risk of adverse effects without enhancing therapeutic efficacy. Maintaining a consistent concentration of the antibiotic in the bloodstream is crucial for its effectiveness, so adherence to the prescribed schedule is strongly emphasized.

Overdose

Symptoms of Phexin overdose are primarily extensions of its adverse effects and may include severe nausea, vomiting, epigastric distress, diarrhea, and hematuria. In the event of a suspected overdose, symptomatic and supportive care is the mainstay of treatment. Gastric lavage may be considered if ingestion was recent. Since Cefalexin is eliminated primarily by the kidneys, ensuring adequate renal function and hydration is important. Hemodialysis can aid in the removal of Cefalexin from the bloodstream and may be employed in cases of significant overdose, particularly in patients with renal impairment. There is no specific antidote.

Storage

Phexin capsules should be stored at room temperature, between 15°C and 30°C (59°F and 86°F), in a tightly closed container, and protected from light and moisture. The oral suspension, once reconstituted with water, should be stored in a refrigerator (2°C to 8°C / 36°F to 46°F) and discarded after 14 days. It is imperative to keep all medications out of the sight and reach of children and pets to prevent accidental ingestion. Do not use the medicine after the expiration date printed on the packaging.

Disclaimer

This information is intended for educational and informational purposes only and does not constitute medical advice. It 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 before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read herein. The content has been compiled from various scientific sources but may not encompass the most recent research or regulatory updates. The manufacturer’s official prescribing information should always be consulted for the most complete and updated data.

Reviews

Clinical studies and extensive post-marketing experience have established Phexin (Cefalexin) as a highly effective and generally well-tolerated antibiotic for a defined spectrum of infections. In systematic reviews, it demonstrates high clinical cure rates for uncomplicated skin and soft tissue infections and streptococcal pharyngitis. Its efficacy in acute cystitis is well-documented, though local resistance patterns should guide its use. The drug’s favorable pharmacokinetics and oral bioavailability are frequently cited advantages in clinical practice. The most common feedback from healthcare professionals highlights its reliability and cost-effectiveness for first-line treatment in appropriate indications. Patient-reported outcomes often note rapid symptom relief, with gastrointestinal disturbances being the most frequently mentioned drawback. Its long history of use provides a robust body of evidence supporting its role in empiric therapy.