What are the special instructions for taking Keflex (Cephalexin)?

Special Instructions for Taking Keflex (Cephalexin)

Keflex (cephalexin) should be taken with or without food, but if gastrointestinal upset occurs, it should be taken with food. The medication must be taken at evenly spaced intervals throughout the day to maintain consistent blood levels, and the full prescribed course should be completed even if symptoms improve before finishing.

Dosing Schedule

Keflex is typically administered according to the following schedules:

• Standard adult dosing: 250-500 mg every 6 hours (4 times daily)

• Alternative adult dosing for certain infections: 500 mg every 12 hours (twice daily) for:

  • Streptococcal pharyngitis
  • Skin and skin structure infections
  • Uncomplicated cystitis in patients over 15 years 1

• Pediatric dosing: 25-50 mg/kg/day divided into equal doses given every 6 hours

  • For streptococcal pharyngitis and skin infections in children over 1 year, doses may be divided and given every 12 hours
  • For otitis media, higher doses of 75-100 mg/kg/day in 4 divided doses are recommended 1

Administration Guidelines

1. Oral suspension preparation:

   • Must be reconstituted by a pharmacist before dispensing
   • After mixing, store in refrigerator
   • Can be kept for 14 days without significant loss of potency 1

2. Duration of therapy:

   • For streptococcal infections: Complete a full 10-day course to prevent complications 2
   • For skin infections: Duration varies based on severity and response
   • For urinary tract infections: Typically 7-14 days 1

3. Special populations:

   • Renal impairment: Dose reduction required for patients with creatinine clearance less than 30 ml/min 3

Important Precautions

1. Allergies: Inform your healthcare provider if you have a history of penicillin allergy, as cross-reactivity can occur

2. Missed doses: Take as soon as remembered unless it's almost time for the next dose. Never double up on doses.

3. Storage:

   • Capsules: Store at room temperature
   • Suspension: Refrigerate after reconstitution and use within 14 days 1

Common Side Effects

• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Skin rashes
• Allergic reactions

Advantages of Keflex

Keflex is absorbed high in the intestinal tract and does not significantly disturb lower bowel flora. It has a low incidence of allergic reactions compared to some other antibiotics and achieves high concentrations in the urine, making it effective for urinary tract infections 3.

Drug Interactions

Be sure to inform your healthcare provider about all medications you're taking, as certain drugs may interact with Keflex.

Remember that completing the full course of antibiotics is essential to prevent the development of antibiotic resistance, even if symptoms improve before the medication is finished.