Disposition of roxithromycin in the epididymis after repeated oral administration

Clinical pharmacokinetics of oral azithromycin in epididymal tissue

OBJECTIVES

Chlamydia trachomatis is one of the major pathogens causing acute epididymitis. Azithromycin (AZM) has a good efficacy against C. trachomatis; however, the ability of AZM to penetrate into human epididymal tissue has not yet been fully elucidated. Here, we examined the appropriate dosage of oral AZM for human epididymal tissue by site-specific pharmacokinetic/pharmacodynamic (PK/PD) analysis.

METHODS

Patients with prostate cancer who underwent orchiectomy were included in this study. All patients received a 1-g dose of AZM before orchiectomy. Both epididymal tissue and blood samples were collected during surgery, and the drug concentrations were measured by high-performance liquid chromatography. All concentration-time data were analyzed with a three-compartment model with first-order absorption and elimination processes to simulate AZM concentrations in serum and epididymal tissue.

RESULTS

A total of 10 patients were enrolled in the current study. For the observed values, the ratio of the epididymal concentration to the serum concentration was 5.13 ± 3.71 (mean ± standard deviation). For the simulated values, the maximum concentrations were 0.64 μg/mL at 2.42 h in serum and 1.96 μg/g at 4.10 h in epididymal tissue. The 24-h concentrations were 0.239 μg/mL in serum and 0.795 μg/g in epididymal tissue.

CONCLUSIONS

The penetration of oral AZM into human epididymal tissue was examined to assess the potential application of AZM for the treatment of acute epididymitis. Based on the previous reports mentioning drug-susceptibility of C. trachomatis, multiple doses of oral AZM 1 g would be recommended for epididymitis based on the site-specific PK/PD.

Microbiology of acute epididymitis in a developing community

OBJECTIVE

To investigate the aetiology of acute epididymitis in a developing community with a view of determining appropriate antimicrobial therapy.

SETTING

City Health Sexually Transmitted Diseases Clinic, King Edward VIII Hospital, Durban, South Africa.

PARTICIPANTS

144 adult men with clinically diagnosed acute epididymitis.

METHOD

Endourethral swab and midstream urine (MSU) specimens were processed to detect sexually transmitted pathogens and urinary tract infections.

RESULTS

The majority of patients (93%) were less than 35 years of age. Neisseria gonorrhoeae and/or Chlamydia trachomatis were detected in 78% of patients: N gonorrhoeae in 57%, C trachomatis in 34% and both in 13%. Escherichia coli was cultured more frequently from MSU specimens of older patients, 30% versus 3%. In 53% of patients urethritis was diagnosed by the presence of inflammatory cells in endourethral smears in the absence of a visible urethral discharge.

CONCLUSION

In our setting of a busy clinic with limited facilities, we recommend the performance of a Gram stain on endourethral specimens from patients with acute epididymitis. If inflammatory cells and Gram negative diplococci are detected, treatment with antimicrobial agents to cover both penicillinase-producing N gonorrhoeae strains and C trachomatis is recommended. If Gram negative diplococci are not detected in the presence of microscopic evidence of urethritis, treatment for chlamydial infection alone is recommended.