The efficacy of antibiotics in improving
The efficacy of Tylosin tartrate in improving smell function has been previously found to be negative, both when used for bacterial and viral infections. Van Zele et al, in a double-blind, placebo-controlled, multicenter study, found no influence of doxycycline treatment on self-reported olfactory loss in 14 chronic rhinosinusitis patients with bilateral nasal polyps. Videler et al administered azithromycin to 29 chronic rhinosinusitis patients (62% with nasal polyps) and a placebo to 31 such patients (42% with polyps). A 12-odor smell identification test was administered at the beginning of the treatment period and at 6 and 12 months during the treatment period. No influence of azithromycin was found. More recently, Reden et al administered, in a randomized double-blind placebo-controlled study, either minocycline (n = 26) or a placebo (n = 29) to patients whose olfactory dysfunction was due to an upper respiratory infection. No influence of the antibiotic on tests of odor identification, detection, and discrimination was observed.
Taking a somewhat different tact, Ramakrishnan et al examined, in a study of 434 medically refractory chronic rhinosinusitis patients, whether the number of days of reported antibiotic use in the 90 days before endoscopic nasal sinus surgery was related to pre-surgical scores on a 12-item smell identification test. No meaningful differences in the olfactory test scores were evident among the groups who had used no antibiotics (n = 163) or had used antibiotics for 1–14 days (n = 102), 15–28 days (n = 69) or more than 29 days (n = 100).
Materials and methods
Results The mean (SEM) UPSIT and PEA threshold test scores are shown in Table 2, along with the P and η values for the ANCOVA comparison of scores across the three groups. Comparisons among the antibiotic groups are shown in the three columns on the far right. Ps< 0.05 are bolded. It is apparent from Table 2 that detection threshold values were nominally lower, i.e., sensitivity was higher, for those individuals in the URI and rhinosinusitis study groups who had taken bactericidal antibiotics for their chemosensory deficit compared to those who had taken either no antibiotic or a bacteriostatic one. This effect reached statistical significance for both the URI group (P = 0.020) and the rhinosinusitis group (P = 0.028). For both of these groups, thresholds were lower for those who had taken bactericidal antibiotics than for those who had taken bacteriostatic antibiotics (respective P = 0.023, P = 0.028). For individuals in the LRI study group, the use or type of antibiotic did not impact olfactory thresholds (all P > 0.50). The odor identification test scores did not meaningfully differ among any of the subject groups, although they were nominally larger in the bacteriocidal group with a rhinosinusitis etiology.
Discussion Our study is in agreement with earlier studies that found no influence of antibiotics on odor identification test scores of patients whose olfactory disturbances were due to chronic rhinosinusitis10, 13 or URIs. They differ, however, from the negative findings of the sole study that measured olfactory thresholds in patients whose chemosensory dysfunction was secondary to URIs. The basis for this difference is not clear. Although our patient population was specifically comprised of persons with olfactory dysfunction significant enough for them to seek help from a specialized smell and taste center, this was also the case with their study. Our sample size was considerably larger (158 vs 55), presumably providing more power to see effects. The possibility also exists that our threshold test is more sensitive than that used in their study. It is noteworthy that some previous studies have found threshold tests to be somewhat more sensitive than odor identification tests to olfactory alterations secondary to chronic renal failure, migraine headaches, iron deficiency anemia, and continuous positive airway pressure (CPAP).23, 24