Cephalexin Monohydrate (Cephalosporin Antibiotic)

Question 1

What is the brand name of cephalexin monohydrate?

Answer 1

Keflex

Question 2

What strength capsules of Keflex are available?

Answer 2

250mg, 500mg, 750mg

Question 3

What strength powder for oral suspension of Keflex is available?

Answer 3

125 mg per 5 mL, and 250 mg per5 mL (following reconstitution)

Question 4

What strength tablets of Keflex is available?

Answer 4

250mg & 500mg

Question 5

What is the FDA approved indication for Keflex? What is the dose?

Answer 5

To be used in infections due to susceptible strains of the following organisms: streptococci, staphylococci, E. coli, P. mirabilis, Klebsiella species, H. influenzae, and M. catarrhalis

Dose: 250 mg to 1 g every six hours. May use 500 mg every 12 hours for streptococcal pharyngitis, skin and skin structure infections and uncomplicated cystitis and patients over 15 years of age.

Children’s Dose: 25 to 100 mg/kg/day in for equally divided doses.

Question 6

What is the mechanism of action of cephalexin monohydrate?

Answer 6

Cephalexin is a first generation cephalosporin which inhibits bacterial cell wall synthesis via acylation of the transpeptidase enzyme.

Question 7

What are the drug interactions for cephalexin monohydrate?

Answer 7

• May alter the absorption of estrogen’s including oral contraceptives.
• Probenecid increases serum concentration.
• May cause a false positive for nonspecific urine glucose tests, for some proteinurea tests, and for direct Coomb’s test.
• May falsely elevate urinary 17-ketosteroid values

Question 8

What are the contraindications for cephalexin monohydrate?

Answer 8

• Contraindicated in patients hyper sensitive to penicillin and or cephalosporins. Estimated incidence of cross sensitivity is 5% to 16%.
• Use with caution in patients with renal function impairment.
• Cases of pseudomembranous colitis have occurred during treatment with cephalosporins.
• Report persistent or severe diarrhea to physician

Question 9

What are the adverse effects of Keflex?

Answer 9

Nausea, vomiting, diarrhea, hives, itching, and rash.

Question 10

What should the RPh tell the patient when counseling them on the use of cephalexin monohydrate?

Answer 10

• Preferably taken on an empty stomach one hour before or two hours after meals with a full glass (240 mL) of water
• Take at even intervals; preferably around the clock
• Complete full course of therapy unless otherwise directed
• Keep suspension refrigerated. Discard unused portion after 14 days. Shake suspension well before using.
• If a dose is missed, take it as soon as possible.