Vomiting is largely attributed to local factors and poor gastric emptying, and should not be treated with antiemetic drugs.16 Cyclizine and prochlorperazine have not proven useful and may carry a higher risk of toxic side-effects in young infants, and in the presence of dehydration. Ondansetron is moderately effective,17 but the cost and quantity required for a clinically significant effect negates general recommendation.
Antiemetic drugs are not recommended Evidence Level A
Abdominal pain is usually spasmodic due to disordered motility, or is associated with colitis in dysentery. Metoclopramide should be considered in severe pain, at a dose of 0.1 mg/kg of body mass to a maximum of 10 mg; a total daily dose of 0.5 mg/kg should not be exceeded.16 The extrapyramidal side-effects of metoclopramide in young infants should warrant caution. Frequent small oral sips of a clear hypotonic glucose-containing fluid correct ketosis and prevent gastric overdistension, in addition to contributing to rehydration. In early gastroenteritis, solids or foods with a high protein, fat or fibre content slow down gastric emptying and may aggravate vomiting. Substitution with a clear, hypotonic fluid may result in earlier cessation of vomiting.
Diarrhoea is the manifestation of secretion/absorption disturbance and disordered motility: a symptom of damage already done in the infected gut. Antidiarrhoeal medication is not advised. Antidiarrhoeal formulations aim to reduce intestinal motility, reduce secretion of water and electrolytes, and adsorb fluid and toxins, thereby reducing the number of stools seen in the diaper; however, none treat the cause of diarrhoea or actual pathology, and their use may be associated with more side-effects in young children than in adults. Furthermore, adsorbents (e.g. kaolin) hide the true extent of water loss, risking underestimation of the amount of fluid required for hydration in severe diarrhoea.
Antibiotic therapy is not indicated in the majority of cases caused by viral infection.18 In bacterial infection, antibiotic therapy generally does not shorten the length of diarrhoea, except when administered early in the case of dysentery (ciprofloxacin for 3 days is recommended).7 Rather, antibiotics are required to prevent or limit the spread of infection to others (e.g. early in cholera), and should be prescribed for evident parenteral infection (e.g. urinary tract infection or otitis media).
Probiotics have variable effect in specific circumstances,19 , 20 and are generally not required, but could be considered in diarrhoea associated with nosocomial infections or antibiotic use. Probiotics are sometimes added to commercial preparations of oral rehydration solutions (e.g. Hydrachoice).21
Vitamin and mineral supplementation is required where the patient’s nutritional state or history suggests the possibility of deficiencies. Zinc acetate (10 - 20 mg/day for 2 weeks) reduces the duration of diarrhoea and recurrence risk in developing countries.22 To date, no comparable studies are available in developed countries; however, it is known that zinc has an effect on mucosal functions involved in absorption of water and rehydration.23 , 24