Lay Summary: Antibiotics and vaginal thrush
Background
Vaginal thrush is a common infection in women. A number of factors may increase the chance of getting vaginal thrush, including pregnancy,
oral contraceptive use, menstrual periods and diabetes. It is generally accepted that recent antibiotic use is also a factor that may
promote the onset of thrush, but there is only limited published evidence to support this notion.
Aim
To compare the occurrence of thrush following the use of antibiotics or antidepressants (a comparison group not suspected to alter the risk of getting thrush).
Method
Information was extracted from studies of six antibiotics (ciprofloxacin, ofloxacin, norfloxacin, cefixime, azithromycin and fosfomycin) and
six antidepressants (fluvoxamine, fluoxetine, paroxetine, sertraline, venlafaxine and nefazodone), all of which were conducted using the
method known as prescription-event monitoring (PEM). The numbers of reports of thrush were determined for women aged over 16 years in each
of the first 7 weeks following a prescription for each of the study drugs. The risks of thrush following the use of each antibiotic, compared
with antidepressants, were calculated for each week and for the overall 7-week period. Women treated with anti-depressants were the most
suitable control group available as they were of a similar age range and the studies were conducted during similar time periods to those of the antibiotics.
Results
Overall, during the first 7 weeks of treatment, there were 188 reports of vaginal thrush in 31,588 women treated with antibiotics (0.6%) and
70 reports in the 45,492 treated with antidepressants (0.15%). The risk of vaginal thrush was greater for antibiotics than antidepressants
for each of the first 3 weeks of treatment. The difference was greatest in the second week when it was estimated to be about 10 times greater
with antibiotics. When information for individual antibiotics was analysed, the risk was increased for 3 weeks after starting treatment for 5
of the drugs. The exception was fosfomycin, a drug for which information was sparse and for which a similar effect could have been missed.
Conclusion
This study shows that, compared to users of antidepressants, users of antibiotics are at increased risk of developing vaginal thrush for 3 weeks after starting treatment