Ok, I am not a doctor but I was a nurse before staying home with my children, so take my advice with a grain of salt. This drug has some rather serious side effects. It s actually an antihistamine. It's been prescribed for severe allergies and possible reduction of migraines. It also acts as an antiserotonin and sedative. It has been used for a relatively long time as an appetite enhancer, but a really what cost for a child? I have generally only seen it prescribed in cases of children who have severe malnutrion due to an underlying chronic medical condition.
I am also the mom of 3 girls- 8, 3.5 and 17 months. The youger 2 are very thin- my 3.5 yr old is 31 lbs and 42 inches tall and my 17 mnth old is 19.5 lbs and 36 in. tall. Neither one has ever been prescribed anything except try to feed them high fat foods like avocado and adding real butter, etc. I do give them both a hemp protein smoothie everyday but that's mostly due to their dairy allergies and the fact that they aren't fond of meat or beans/legumes. I would really look for a second opinion on this one- my gut feeling is that this might be too rash of a decision. I'm sure there are lots of people out there who have used it sucessfully but my thinking is, if there isn't another underlying problem, maybe other things need to be done 1st. Has he always been thin? Maybe it is part genetics? Does he have speech/ swallowing/ texture issues? I guess waht my stance on this is, 1st exhaust all other options, then if nothing is resolved/works, move to the drug. There are potentially long term nervous system side-effects from long term use and it kind of seems like a band-aid to a situation without exhausting all other possibilites first. Just my 2 cents, good luck!