Is Ceflex (Cefalexin) a Topical Antibiotic?
No, cefalexin (also spelled cephalexin) is not a topical antibiotic—it is an oral and systemic antibiotic administered by mouth as capsules, tablets, or oral suspension. 1
Route of Administration
- Cefalexin is formulated exclusively for oral administration as a semisynthetic first-generation cephalosporin antibiotic available in capsule, tablet, and oral suspension forms 1
- The drug is absorbed in the upper intestine (not from the stomach) and achieves rapid systemic distribution to tissues throughout the body 2
- There is no topical formulation of cefalexin available or approved for use 1
Clinical Applications
Cefalexin is used systemically for:
- Skin and soft tissue infections caused by streptococcal and staphylococcal bacteria, where it achieves cure rates of 90% or higher 3
- Upper respiratory tract infections including pharyngitis, tonsillitis, and otitis media (except those caused by Haemophilus influenzae) 4
- Bone and joint infections in children, where high-dose oral therapy (45 mg/kg three times daily, maximum 1.5 g) is effective as continuation therapy 5
- Urinary tract infections, achieving urine concentrations of 500-1000 μg/mL following standard oral doses 2
Mechanism of Systemic Action
- After oral administration, cefalexin is totally and rapidly absorbed in the upper intestine and distributed systemically to tissues 2
- The drug does not penetrate into host tissue cells, which likely accounts for its low incidence of side effects 2
- 70-100% of the dose is excreted unchanged in urine within 6-8 hours, indicating no metabolism and complete systemic circulation 2
Common Pitfall
Do not confuse oral antibiotics with topical antibiotics. While cefalexin is highly effective for skin and soft tissue infections, it works systemically after oral absorption—not through topical application to the skin surface 3. For topical treatment of superficial skin infections, entirely different antibiotic formulations (such as mupirocin or fusidic acid ointments) would be required.