Cephalexin Dosing for Male UTI

For male UTI, which is classified as a complicated UTI, cephalexin should be dosed at 500 mg orally four times daily for 7-14 days. 1

Understanding Male UTI Classification

Male UTIs are always considered complicated UTIs according to the European Association of Urology (EAU) guidelines, regardless of other factors 2
Male gender is specifically listed as a complicating factor in UTIs in Table 7 of the EAU guidelines 2
Complicated UTIs have a broader microbial spectrum than uncomplicated UTIs and higher likelihood of antimicrobial resistance 2

The FDA-approved dosing for cephalexin in UTIs is 500 mg every 6 hours (four times daily) 1
For uncomplicated cystitis in patients over 15 years of age, 500 mg every 12 hours may be used, but this does NOT apply to male UTIs 1
The total daily dose should be within 1-4 grams per day 1

For complicated UTIs, therapy should be continued for 7-14 days 1
This longer duration is necessary because male UTIs are more difficult to eradicate compared to uncomplicated infections 2

While recent studies have examined twice-daily dosing of cephalexin for UTIs:

A 2023 study found no significant difference in treatment failure between twice-daily and four-times-daily dosing for uncomplicated UTIs in females (12.7% vs 17%, p=0.343) 3
A 2025 study comparing twice-daily versus four-times-daily cephalexin for both uncomplicated and complicated UTIs found no statistically significant difference in treatment failure rates (18.7% vs 15.0%, p=0.465) 4
However, for the complicated UTI subgroup (which would include male UTIs), treatment failure rates were 27.3% vs 30.3% (p=0.786) between twice-daily and four-times-daily dosing 4

The microbial spectrum in complicated UTIs includes E. coli, Proteus spp., Klebsiella spp., Pseudomonas spp., Serratia spp., and Enterococcus spp. 2
Appropriate management of any underlying urological abnormality is mandatory for successful treatment 2
If symptoms don't improve or worsen, consider switching to parenteral therapy or broader-spectrum antibiotics based on culture results 2
For severe infections, the dosage may need to be doubled 1

If cephalexin is not appropriate due to resistance or other factors, alternative regimens for complicated UTIs include:

Fluoroquinolones (if local resistance is <10%) 2
Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days 2
For parenteral therapy: extended-spectrum cephalosporins, aminoglycosides, or piperacillin/tazobactam 2

Urine culture should be obtained before starting therapy 2
Consider follow-up cultures after completion of therapy to confirm eradication 2
Monitor for treatment failure, which may indicate resistant organisms or underlying anatomical abnormalities 2