Brief Answer:
You can give ondensetron

Detailed Answer:
Hello

Thanks for the query

You can give ondensetron syrup the dose is 2 mg/dose three to four times a day depending on the severity. Ondensetron is an antiemetic and most of the syrup contains 2 mg/5 ml,so the dose will be 5 ml three to four times a day.
Along with ondensetron give Lansoprazole dispersible tablet.The average weight of 20 months old child is about 10-12 kg.The dose for this age will be about 10 mg once a day.The tablet comes in a strength of 15 mg.One third tablet once a day will do.Please get these prescribed by a physician.
Repeated vomiting can lead to dehydration.Once the vomiting stops give him plenty of fluids to avoid dehydration.
Most of the time the vomiting in this age is due to some gastritis and this responds well with these medications.
If the vomiting persists,baby becomes lethargic or there is decrease in urinary frequency consult your doctor.

I hope this helps.
Please do ask if you have any more query.
Regards

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Brief Answer:
Your diet schedule is superb,this may be viral gasteroenteritis

Detailed Answer:
Thanks for follow up

The loose stool following vomiting is quite common in this age group.I was about to tell you in my previous reply for the possibility of loose stool in next one or two days.
The green color of stool is due to increased intestinal motility.Due to this increased motility the process of change in color of pigments which are responsible for yellowish color of stool gets hampered.

I really appreciate the diet content and schedule.Usually I suggest to discontinue the milk due to transient lactose intolerance during diarrhea.But,as butter milk contains minimum lactose,you can continue it.
I have gone through the prescription there is lansoprazole,probiotic and antibiotic but no antiemetic.
That may be the reason his vomiting has not stopped.
The loose stool may persist for 5-6 days but vomiting should subside.
The main aim of management is to prevent dehydration by giving plenty of fluids.
I suggest you to give ondensetron as advised earlier.
If vomiting and loose stool both continues there is high chance of dehydration due to poor oral acceptance.
I hope the vomiting should improve with this.But if it persists,he may need injectable antiemetic.
Also give Zinc syrup as it helps in early recovery from loose stool.

Wish you baby speedy recovery.
Please let me know if you need any further help/clarification.

Regards

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