Vancomycin

Additional information

Pharmacokinetics and dosing

Pharmacokinetic studies have shown that women have lower clearance than men, varying from 15-25% [1-3]. A small study (26 men, 4 women) showed that women had 34% lower clearance than men, however, since the study included very few women the results might be skewed  [2]. One study also showed that women had higher volume of distribution than men when comparing patients of similar age and body weight. These sex differences appeared to be greater in obese patients [3].

Adequate concentrations of vancomycin in critically ill patients are attained by using a weight-based IV loading dose followed by a continuous IV infusion. A study (154 men, 73 women) showed that female sex was associated with early (<48h) adequate vancomycin levels in critically ill patients (odds ratio 4.2, 95%CI 1.6-10.9) [4]. Comparable results where showed in a similar study in septic patients [5].

Effects

No placebo-controlled studies of sex differences in response to vancomycin have been found. Studies comparing vancomycin and metronidazole in treatment of Clostridium difficileinfection have not shown any sex differences in response [6, 7] or risk of second recurrence [8].

Adverse events

High doses of vancomycin are associated with increased risk of nephrotoxicity. A multivariate analysis of 165 men and 123 women showed no sex or age differences in the risk (odds ratio 0.99).  The multivariate analysis showed Afro-Americans, patients with heart failure or metastatic disease to have a higher risk [9].

Reproductive health issues

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