TREATMENT OF UTI IN WOMEN WITH NEGATIVE URINE DIPSTICK RESULTS
Some symptoms improve more quickly with the use of antibiotics.
According to a new study, women who present with dysuria but have negative urine dipstick results obtain relief of symptoms more quickly when treated with antibiotics, compared with those who are not.
Fifty-nine women with complaints of dysuria and urinary frequency prompting a visit to the primary care health practitioner were recruited over a two-year period for the double-blind trial. The subjects were eligible to participate in the study if their urine samples upon dipstick were negative for leukocytes and nitrites, two indicators specific to urinary tract infection (UTI). Once the negative results were confirmed, the subjects were randomized into two arms-one in which 300 mg of the antibiotic trimethoprim was taken daily for three days, and another in which a placebo was taken. The subjects completed questionnaires concerning their symptoms and histories and then kept week-long records of any increases or decreases in the severity of symptoms. After the seven days, the researchers contacted the women by telephone to further assess whether they still had symptoms, the primary outcomes being the absence of dysuria and the median time to the resolution of it.
In the trimethoprim treatment arm, women who had presented with dysuria experienced complete relief of the symptom within a median interval of three days. Comparatively, women in the placebo arm had the symptom for five days. In 24% of women in the trimethoprim arm, dysuria persisted on the third day of therapy, compared with 74% of those who received the placebo. The results remained consistent, in favor of subjects in the trimethoprim treatment arm, on the seventh day-10% of them still experienced dysuria at that point, compared with 41% of women taking the placebo. Trimethoprim treatment also yielded favorable results in the duration of feverishness and shivers when compared with placebo, two days versus six days, respectively.
Interestingly, there was no discrepancy in the interval to resolution of the symptom of frequency-in both arms it was five days. Similarly, in regard to other symptoms that were measured, such as abdominal pain and itching, treatment with trimethoprim did not effect a faster resolution.
The findings suggest that the use of trimethoprim could be beneficial in the reduction of the symptoms of dysuria in uncomplicated UTI in which there is a negative urine dipstick result. The authors concede, however, that such a practice could contribute to the overuse of antibiotic therapy, thereby rendering women unnecessarily vulnerable to adverse events and possible bacterial resistance.-AK
Richards D, et al. BMJ 2005;331(7509);143.
HEART DISEASE AND ANTIBIOTIC TREATMENT OF C. PNEUMONIAE
No benefit has been found.
Gatifloxacin.
It has been found that elevated titers of antibodies to Chlamydia pneumoniae are present in patients with atherosclerotic plaques, and researchers therefore have suggested that the use of antibiotic therapy could decrease the risk of cardiovascular events and disease in that population. But a recent study reports that there is no benefit conferred by such preventive antibiotic therapy.
To test the efficacy of gatifloxacin (an antibiotic of the fluoroquinolone [FQ] class known to be effective against C. pneumoniae) in decreasing cardiovascular events and disease, 4,162 patients who had been hospitalized for an acute coronary syndrome (either acute myocardial infarction or high-risk unstable angina) within the preceding 10 days were enrolled in a double-blind, two-year study. They were given either 400 mg of the drug daily during an initial two-week period of therapy that began two weeks after randomization and was followed by a 10-day course every month for the duration of the study, or a placebo. The patients were seen at follow-up visits at determined intervals.
At the end of the study, 23.7% of the patients in the gatifloxacin group had suffered myocardial infarction, documented unstable angina necessitating rehospitalization, revascularization (performed at least 30 days after randomization), stroke, or death from any cause, compared with 25.1% of the participants in the placebo group. Although the antibiotic has been shown to be effective against C. pneumoniae infection, its use in patients participating in the study yielded no statistically significant reduction in cardiovascular events, despite the association between the bacteria and the development of atherosclerosis.
This off-label use of FQ antibiotics should be approached with caution. Gatifloxacin holds the potential to prolong the QT interval in some patients, including those with uncorrected hypokalemia, and those receiving antiarrhythmic agents of either class IA (quinidine, procainamide) or class III (amiodarone, sotalol). Nurses providing care to cardiac patients who are taking FQ antibiotics should take careful note of any changes in their statuses or symptoms.
Azithromycin.
A recently published study reports that azithromycin therapy is no more effective than a placebo in diminishing the risk of cardiac events in patients with stable coronary heart disease.
After the presence of C. pneumoniae in atherosclerotic lesions had been demonstrated in a series of four independent investigations, the double-blind study, conducted from April 1999 to May 2000, investigated the effects of a single weekly dose of azithromycin in patients with stable coronary heart disease, 4,012 subjects who were randomly assigned to take either 600 mg of the drug or a matching placebo tablet once weekly for a year. Azithromycin, a macrolide antibiotic, was selected for the study because it has a long intracellular half-life that allows once-weekly rather than once-daily dosing. Additionally, chlamydiae have not developed a resistance to the macrolides, which also have been shown to produce few adverse reactions. Patients were monitored for 12 months and interviewed in person or by telephone at determined intervals to identify any adverse effects and reactions and to monitor compliance with the regimen.
At the end of the study, 446 patients who had taken azithromycin had suffered a composite of death attributable to coronary heart disease, nonfatal myocardial infarction, coronary revascularization, or hospitalization for unstable angina, compared with 449 patients in the placebo group who had. The results were not different when the study participants were divided according to age, gender, smoking status, the presence or absence of diabetes mellitus, or C. pneumoniae serologic status at baseline.
The researchers concluded that the one-year course of a weekly dose of azithromycin did not change the rate or risk of cardiac events in patients with stable coronary heart disease.-PWF
Cannon CP, et al. N Eng J Med 2005; 352(16):1646-54; Grayston JT, et al. N Eng J Med 2005; 352(16):1637-45.