Impact of compliance and side effects on the clinical outcome of patients treated with oral erythromycin.

STUDY OBJECTIVE: To determine the relationship among compliance, side effects, and self-reported outcome for patients in an erythromycin trial. DESIGN: A retrospective analysis of data from a multicenter, prospective, single-blind, randomized trial. SETTING: Five metropolitan ambulatory care offices. PATIENTS: The 252 adults (> 18 yrs) were prescribed oral erythromycin 1.0 g/day (base equivalent) for infectious disorders. INTERVENTION: Subjects received erythromycin for 10 days and reported compliance, drug efficacy, and side effects in a daily diary. Compliance was measured by tablet count. RESULTS: A negative correlation was found between gastrointestinal symptom severity score and percentage of tablets taken (p < 0.001). A significant positive correlation was seen between compliance and outcome (p < 0.001). Subjects who took greater than 80% of the drug achieved the treatment goal more frequently than those taking 80% or less (94% vs 59%, p < 0.001). CONCLUSIONS: Side effects of erythromycin adversely affected compliance. Compliance had a positive effect on self-reported outcome.

A comparison of the gastrointestinal side effects of two forms of erythromycin.

BACKGROUND: The gastrointestinal (GI) side effects of erythromycin frequently limit therapy and compliance. PCE Dispertab, a more expensive brand of erythromycin, has been promoted as a well-tolerated new dosage form; however, no studies compare its GI side effects with those of other forms of erythromycin. We compared erythromycin PCE (particles-in-tablet) with E.E.S. (erythromycin ethylsuccinate) to determine whether there is a difference in the incidence and severity of GI side effects. METHODS: This was a multicenter, prospective, single-blind, randomized trial. Observers, but not participants, were blinded to the brand of erythromycin taken until after data analysis. We enrolled ambulatory patients who were at least 18 years old and weighed at least 90 lb for whom erythromycin had been prescribed at a dosage of 1.0 g/d. Subjects were given either the particles-in-tablet form, 333 mg three times daily, or the ethylsuccinate form, 400 mg four times daily, for 10 days and asked to report efficacy, compliance, and the frequency and severity of four GI symptoms (abdominal pain, nausea, vomiting, and diarrhea) in a daily diary. RESULTS: There were no significant differences between the particles-in-tablet and ethylsuccinate forms in incidence of GI side effects (63% and 61%, respectively), average daily GI symptom severity score (0.62 and 0.68, respectively), and GI-related discontinuations (8.5% and 8.2%, respectively). The incidence of moderate or severe nausea was 5% for the particles-in-tablet form and 25% for the ethylsuccinate form (P < .001). CONCLUSIONS: Although ethylsuccinate caused a higher incidence of moderate to severe nausea, there were no differences in the three main outcome measures: incidence of GI side effects, average daily GI-symptom severity score, and GI-related discontinuations. Therefore, we support prescribing erythromycin ethylsuccinate as a first line of treatment because it costs less.