Azitromycin

Additional information

Pharmacokinetics and dosing

No studies with a clinically relevant sex analysis regarding the pharmacokinetics or dosing of azithromycin have been found.

Effects

A meta-analysis has estimated the efficacy of a 1 g single-dose of azithromycin for treatment of genital Mycoplasma genitaliuminfection (820 men, 244 women, 426 unknown sex). The efficacy, measure as pooled microbial cure, was 78.9% for men and 86.8% for women, but the difference was not statistically significant. The overall efficacy in this study was lower than in previous ones [1].

The efficacy of azithromycin in adolescents with Chlamydia trachomatis infection has been evaluated in a prospective study (99 males, 29 females; 15-19 years old). Patients received a single-dose of 1 g oral azithromycin. Azithromycin efficacy was similar, 95% among male patients and 100% among female patients [2]. A meta-analysis (in total 726 men, 817 women) has shown that azithromycin and doxycycline are equally efficacious in achieving microbial cure in treatment of genital Chlamydia trachomatisinfection in both men and women [3].

Results from a multicenter trial of single-dose azithromycin vs. ceftriaxone for uncomplicated gonorrhea, showed that cure rates were similar in men and women for azithromycin [4].

In a retrospective observational cohort study, patients (44 men, 59 women) with severe asthma or bronchiectasis were treated with clarithromycin or azithromycin in addition to their standard treatment. Men with bronchiectasis were more likely to respond (symptom score) to treatment with macrolides than women, 53% vs. 27% [5].

Daily use of 250 mg azithromycin in patients with chronic obstructive pulmonary disease has been shown to decrease acute exacerbations to same extent in men and women [6].

A study has evaluated addition of azithromycin to high-risk patients operated for chronic rhinosinusitis failing standard management (34 men, 23 women). Patients received 250 mg three times a week. All four patients who did not respond to azithromycin treatment were women. The authors speculate that there may be a sex bias to the response to azithromycin addition [7].

Adverse effects

Azithromycin use is associated with an increased risk of death from cardiovascular causes, and the risk is similar in men and women (p=0.73) [8].

Azithromycin has been associated with prolonged QT-interval and a risk of Torsades de pointes ventricular tachycardia [8]. I the Swedish PDR, it is recommended to be careful when prescribing azithromycin to patients with ongoing proarrhythmic conditions, especially women and the elderly [9]. Among the known risk factors of drug-induced ventricular arrhythmias are female sex, hypokalemia, bradycardia, base line QT-prolongation and use of other QT-prolonging drugs [10].

Reproductive health issues

Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).