Keftab, the branded formulation of cephalexin, is a first-generation cephalosporin antibiotic indicated for the treatment of a wide spectrum of bacterial infections. It functions by inhibiting bacterial cell wall synthesis, leading to osmotic instability and cell lysis. This oral medication is valued in clinical practice for its reliable bioavailability and established efficacy against common pathogens, making it a frontline choice for uncomplicated community-acquired infections. Its pharmacokinetic profile supports convenient dosing schedules that promote patient adherence.

Features

• Active pharmaceutical ingredient: Cephalexin monohydrate
• Available in 250 mg, 500 mg, and 1 g oral tablet formulations
• Demonstrated in vitro activity against Gram-positive aerobes including Staphylococcus aureus (methicillin-susceptible isolates) and Streptococcus pyogenes
• Activity against some Gram-negative organisms including Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae
• Rapid absorption following oral administration with peak serum concentrations achieved within one hour
• Mean plasma half-life of approximately 0.5–1.2 hours in adults with normal renal function
• Excreted largely unchanged in the urine via glomerular filtration and tubular secretion

Benefits

• Provides bactericidal action against susceptible pathogens, rapidly reducing microbial load
• High oral bioavailability ensures systemic therapeutic concentrations are achieved without need for parenteral administration in appropriate cases
• Established safety profile with extensive clinical use history spanning decades
• Dosing flexibility allows for adjustment based on infection severity and patient renal function
• Effective as monotherapy for many common outpatient infections, reducing need for combination regimens
• Lower risk of Clostridioides difficile-associated diarrhea compared to broader-spectrum alternatives

Common use

Keftab (cephalexin) is clinically indicated for the treatment of bacterial infections caused by susceptible strains of designated microorganisms. Common uses include uncomplicated skin and skin structure infections such as cellulitis, impetigo, and abscesses often caused by Staphylococcus aureus or Streptococcus pyogenes. It is also employed in the management of respiratory tract infections including pharyngitis, tonsillitis, and community-acquired pneumonia of mild to moderate severity when caused by susceptible bacteria. Additionally, Keftab is utilized for uncomplicated urinary tract infections, particularly those caused by E. coli, P. mirabilis, and K. pneumoniae. Off-label uses may include prophylaxis in certain surgical procedures and treatment of bone infections when caused by susceptible organisms, though these applications require careful clinical judgment.

Dosage and direction

The dosage of Keftab must be individualized based on the infection site, severity, and causative organism, as well as the patient’s renal function. For adults, the usual dose ranges from 250 mg to 1 g administered orally every 6 to 12 hours. For mild to moderate upper respiratory infections, 250 mg every 6 hours is often sufficient. More severe infections or those involving less susceptible organisms may require 500 mg every 8 hours or 1 g every 12 hours. Pediatric dosing is typically based on body weight, generally 25–50 mg/kg/day divided into 2–4 doses, not to exceed adult dosing. In patients with impaired renal function (creatinine clearance <50 mL/min), dosage reduction or extended dosing intervals are necessary—consult specific dosing guidelines for creatinine clearance adjustments. Tablets should be swallowed whole with a full glass of water and may be taken with or without food, though administration with food may minimize gastrointestinal upset. Complete the full prescribed course of therapy even if symptoms improve earlier to prevent development of resistance.

Precautions

Prior to initiating Keftab therapy, obtain a thorough patient history including previous hypersensitivity reactions to beta-lactam antibiotics. Use with caution in patients with a history of gastrointestinal disease, particularly colitis, as antibiotic use can predispose to C. difficile-associated diarrhea. Monitor renal function periodically during prolonged therapy or in patients with pre-existing renal impairment, as cephalexin is primarily excreted renally. In patients with significant renal dysfunction, accumulation may occur, increasing the risk of adverse effects. Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi; monitor for superinfection. Perform culture and susceptibility testing whenever possible to confirm pathogen susceptibility. False-positive reactions for glucose in the urine may occur with Benedict’s or Fehling’s solutions but not with enzyme-based tests.

Contraindications

Keftab is contraindicated in patients with known hypersensitivity to cephalexin or any component of the formulation. Cross-sensitivity with other beta-lactam antibiotics may occur; it is contraindicated in patients who have experienced anaphylactic reactions to penicillins. Do not administer to patients with a history of severe immediate hypersensitivity reactions (e.g., anaphylaxis, Stevens-Johnson syndrome) to any cephalosporin. Avoid use in cases where the infection is documented or strongly suspected to be caused by a nonsusceptible organism, including methicillin-resistant Staphylococcus aureus (MRSA) or extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae.

Possible side effect

The most commonly reported adverse reactions associated with Keftab involve the gastrointestinal system, including diarrhea (occurring in up to 5% of patients), nausea, vomiting, abdominal pain, and dyspepsia. Hypersensitivity reactions may present as rash, urticaria, pruritus, and, rarely, serum sickness-like reactions or anaphylaxis. Other reported side effects include dizziness, fatigue, headache, genital pruritus or vaginitis, and transient elevations in hepatic transaminases. Hematologic effects such as eosinophilia, neutropenia, thrombocytopenia, and positive direct Coombs test have been reported infrequently. As with many antibiotics, pseudomembranous colitis caused by C. difficile may occur and can range in severity from mild to life-threatening.

Drug interaction

Concurrent use of probenecid with Keftab may result in increased and prolonged cephalexin blood levels due to decreased renal tubular secretion. Administration with metformin may increase metformin exposure; monitor and adjust metformin dose if necessary. Though clinical evidence is limited, theoretical interactions exist with other nephrotoxic agents (e.g., aminoglycosides, loop diuretics) which may enhance nephrotoxicity—monitor renal function. Keftab may potentiate the effect of oral anticoagulants like warfarin; monitor prothrombin time and INR. False-positive urinary glucose tests may occur with certain reagents. No clinically significant interactions have been reported with oral contraceptives, but as with all antibiotics, patients should be advised of the theoretical risk of reduced contraceptive efficacy.

Missed dose

If a dose of Keftab 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. Do not double the dose to make up for a missed one, as this increases the risk of adverse effects without enhancing efficacy. Maintenance of consistent serum levels is important for optimal antibacterial effect, so patients should be counseled on adherence. Setting reminders or aligning doses with routine daily activities can help prevent missed doses.

Overdose

Symptoms of Keftab overdose may include nausea, vomiting, epigastric distress, diarrhea, and hematuria. In cases of significant overdose, particularly in patients with renal impairment, neurotoxicity including seizures may occur. Management is primarily supportive and symptomatic. Gastric lavage may be considered if ingestion was recent. Hemodialysis can significantly enhance the removal of cephalexin from the bloodstream and may be employed in severe cases, especially with concomitant renal failure. There is no specific antidote. Contact a poison control center for latest guidance in overdose management.

Storage

Store Keftab tablets at controlled room temperature, 20°–25°C (68°–77°F), with excursions permitted between 15°–30°C (59°–86°F). Keep the container tightly closed to protect from moisture and light. Do not store in bathrooms or other areas with high humidity. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging. Properly discard any unused medication once the therapy course is completed; do not flush or pour into drains unless instructed. Consult a pharmacist regarding take-back programs or proper household disposal methods.

Disclaimer

This information is intended for educational and professional medical reference purposes only and does not constitute medical advice. It is not a substitute for professional clinical judgment, diagnosis, or treatment. The prescribing physician must rely upon their own training, experience, and knowledge of the patient to make diagnoses and determine appropriate therapies and dosages. Always consider official prescribing information and current clinical guidelines. The manufacturer and distributor are not liable for any outcomes resulting from the use or misuse of this information. Patients should be instructed to consult their healthcare provider with any questions regarding their medical condition or treatment.

Reviews

Clinical studies and post-marketing surveillance over decades have established Keftab (cephalexin) as a well-tolerated and effective antibiotic for susceptible bacterial infections. In clinical trials for skin and soft tissue infections, cephalexin demonstrated clinical cure rates exceeding 85% in compliant patients. For uncomplicated urinary tract infections, it shows efficacy comparable to other first-line agents when the pathogen is susceptible. Physician reviews frequently note its reliability for common outpatient infections, favorable side effect profile, and convenience of dosing. Some reviews caution against its use in regions with high rates of resistant organisms and emphasize the importance of susceptibility testing. Patient-reported outcomes often highlight effectiveness in resolving infections, though gastrointestinal side effects are a noted drawback for some individuals. Overall, it remains a valued option in the antimicrobial arsenal.