Conditions: Gastroparesis
Keywords: Gastroparesis Gastroparesis Treatment Gastric Emptying Prokinetic Agents Macrolides Erythromycin Azithromycin Erythromycin Cardiac Side-effects Erythromycin drug interactions AZI
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 26
Healthy volunteers: no

Brief summary:
Erythromycin is effectively used in the treatment of Gastroparesis (GP) patients. In susceptible patients however, it has been associated with sudden cardiac death due to prolongation of QT intervals and subsequent cardiac risks through its interaction some other drugs. Azithromycin (AZI) is a macrolide antibiotic but does not have the mentioned druf interactions , has fewer gastrointestinal side effects, and fewer risks of QT prolongation and cardiac arrhythmias. Consequently, AZI avoids drawbacks of dosing with erythromycin and may be preferred as a prokinetic agent in patients on other concomitant medications.

We hope to demonstrate the effectiveness of Azithromycin (AZI) as compared to Erythromycin in the treatment of Gastroparesis (GP), and later, form the framework for larger randomized-controlled parallel studies to investigate use of AZI for treatment of GP.

Our novel hypothesis is to determine whether AZI can be used to treat GP.

Detailed description:
Gastroparesis (GP) is a chronic gastrointestinal motility disorder resulting from delayed transit of gastric contents from the stomach into the duodenum in the absence of mechanical outlet obstruction. The symptoms of GP are variable but include early satiety, bloating, nausea, vomiting, and epigastric abdominal pain. Although the true prevalence of the disorder is unknown, symptoms suggestive of GP are present in 7-15% of the population with an estimated one-third of diabetic patients in tertiary care settings having abnormal gastric emptying studies. Yet, despite the significant healthcare and economic costs due to frequent hospitalization in these patients, treatment of GP is difficult due to the lack of available treatment options and the often potential side effects of available prokinetic agents, including cardiac side effects such as QT prolongation, sudden cardiac death, and torsade de pointes.

One such medication used for treatment of GP is erythromycin. Erythromycin has its drawbacks. Several reports of cardiac arrhythmias associated with use of either oral or intravenous (IV) Erythromycin have been reported. This finding sparked our interest in another macrolide, Azithromycin (AZI), which does not have the drug-drug interactions as seen with erythromycin and is not metabolized by the CYP3A inhibitors, therefore having fewer cardiac side effects.

In This study our primary goal is to determine whether AZI can be used to treat GP.

Arms:
arm 1: 200mg/5ml elixir administered orally three times a day half an hour prior to meals. arm 2: The dose of Azithromycin was determined based on our dose response curve obtained on 10 healthy subjects who were given three different doses of Azithromycin, 50 mg, 100 mg and 133 mg and underwent breath testing to determine the gastric emptying half-time. These doses were determined based on a maximum safe dosage per day of Azithromycin of 400 mg given the medication would then be administered three times daily before meals. The appearance of the medication (azithromycin) and administration period was then identical to that of Erythromycin, i.e. 5ml elixir administered orally three times a day half an hour prior to meals. The total daily dosage of Azithromycin was determined after obtaining the dose- response analysis.

Interventions: intervention 1: Erythromycin intervention 2: Azithromycin
Intervention descriptions: intervention 1: 200mg/5ml elixir administered orally three times a day half an hour prior to meals. intervention 2: The dose of Azithromycin given was determined based on the following study on 10 healthy subjects. In random order, each of ten healthy subjects underwent OBT studies following administration of AZI, at doses of 50mg, 100mg, and 133mg. The T½ and Tlag was then compared for the three doses by a randomized block analysis using Analysis of Variance followed by Tukey's multiple comparison. Results: The T½ for each of the respective doses of AZI (50mg, 100mg, and 133mg) was 129 ± 27, 128 ± 31, and 128 ± 16 minutes (p = 0.98). This data suggested that AZI at doses of 50mg, 100mg and 133 mg have fairly similar activity in its effects on gastric emptying in healthy subjects. Based on this analysis , we decided to use a dose of 50 mg/5 ml for administered TID prior to meals.

Protocol document: