It appears he is having an episode of viral gastroenteritis (stomach flu). This presents with vomiting and diarrhoea, which may be preceded by headaches and flu like symptoms.
Treatment for this is mainly supportive:
Plenty of fluids., this is most important to prevent any dehydration. He should take small sips continuously of any fluids like fruit juices, plain water, etc.
If the symptoms of vomiting and diarrhoea are very severe, he can take the following OTC medicines, but it is better if they can be avoided and he gets over this naturally:
Loperamide (one brand name: Imodium): This is for diarrhoea if it is severe. the dosage is 2 caplets after the first loose stool, then 1 caplet after each loose stool that follows. Take no more than 4 caplets or 8 teaspoonfuls in 24 hours
Bismuth subsalicylate (brand names: Kaopectate, Pepto-Bismol): This is for vomiting if it is severe. The usual dose is 2 tablespoonfuls every half-hour to one hour if needed. He should not take more than 16 tablespoonfuls of the regular-strength suspension or 8 tablespoonfuls of the concentrate in twenty-four hours
He may be having some acid reflux along with this, he should also take Tab. Zantac 150 mg once daily for this. The bismuth will also help, or he can take Mucaine gel antacid 2-3 tsf thrice daily
If abdominal cramping is very severe, he may need to take antispasmodics for abdominal cramps, these include drugs like Antispas, Antispasmodic, Barbidonna,
etc.Antispasmodics are perscription drugs, and he has to approach a doctor for this.
He will need to report to the doctor if his diarrhea is so severe he gets dehydrated, or he passes blood in vomit or stools. Viral gastroenteritis usually resolves spontaneously. He will also need to see his doctor if it persists for more than 3 days.
You can look up these sites for some more info: http://www.medicinenet.com/gastroenteritis/article.htm http://www.mayoclinic.com/health/viral-gastroenteritis/DS00085/DSECTION=1
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