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Guideline for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings, 2011

Evidence Table Q3 - Medications

Author, Yr (Ref) Study Design Quality Study Objective Population and Setting N Results Comments Ref ID_Data extracted by

Rossignol, JF; 2006 202

Randomized Controlled Trial


To evaluate nitazoxanide 500mg vs placebo given to adults or adolescents twice daily for 3 days for the resolution of symptoms due to viral gastroenteritis.

Patients at least 12 years of age with gastroenteritis presenting to outpatient clinics at a university hospital in Egypt.

50 outpatients.

Nausea in patients with norovirus vs other viral infections – 6/13 (46%) vs 1/32 (3%); p=0.0013

Time from first dose to symptom resolution
All results nitazoxanide vs placebo in days (IQR); p value
Overall – 1.5 (0.5-2.5) vs 2.5 (1.5-4.5); <0.0001
For Rotavirus infection – 1.5 (0.5-1.5) vs 2.5 (1.5->6.5);0.0052
For norovirus infection – 1.5 (1.5-1.5) vs 2.5 (1.5-6.5); 0.0295

Patients with diarrhea (≥3 diarrheal stools per day) and stool-positive for rotavirus, norovirus, or adenovirus were eligible for enrollment.

Outcome was resolution for at least 72 hours of all symptoms of viral gastroenteritis that were present at enrollment.

A sample size of 19 patients per group, with a 0.05 level two-sided log-rank test for equality of survival curves, had 80% power to detect a difference between an 85% response rate for 1 group and a 40% response rate for a second group at a given time. A sample size of 25 patients per group allowed for exclusion of up to 20% due to other identified causes of diarrhea.


Gustafson, TL; 1983 203

Retrospective controlled study


To determine whether certain medications protected patients from symptomatic disease during a norovirus outbreak.

Patients and staff in a chronic-care hospital in Tennessee.

Cases – 22 employees and 31 patients.

Controls – 14 employees and 25 patients.

55% of elderly psychiatric patients and 61% of nursing employees.

Protective medications
Attack rates; p values
Patients only on antipsychotic drugs vs on antipsychotic drugs plus trihexyphenidyl or benztropine – 71% vs 14%; 0.013

Patients on psyllium hydrophilic mucilloid vs not receiving psyllium: 27% vs 71%; 0.012

Two case definitions used:
For hospital personnel –  any person with vomiting or diarrhea (≥1 liquid stools/ day), or two of the following symptoms (abdominal pain, abdominal cramps, or nausea).
For patients – any patient with vomiting or diarrhea.

Power and sample size not reported.



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