I have a 5 year old boy that has ADHD and has been on Focalin XR 15mg. The meds aren't strong enough but they are scared to up his meds more because he is 35 lbs. They want me to put him in a day treatment program. Do have any tips for me to get him to eat and to listen to me because I'm starting to get really depressed about things.
Unfortunately loss of appetite is the side effect of stimulant medication that can't really be avoided. Consider a holiday from the medication on weekends to get his appetite back or give a dose just after breakfast. You could also try to increase the caloric count of his foods so that he'll get more calories in a smaller amount. Such as milk shakes, grilled cheese sandwiches, peanut butter on crackers. Also you can have his doctor prescribe Pediasure- a nutritional supplement. It's available over the counter but some insurances will pay for it if it's considered medical treatment.
Try your best not to get into power struggles over his food and lack of interest in eating. You'll only lose and in the end drive him further away from eating. A thin but otherwise healthy child is ok. Be sure your pediatrician is comfortable with this.
Also I encourage you to look into the day treatment program. I've seen great success with some kids whose behavior was able to be managed with certain "Behavior Modifications" such as positive feedback and specific rewards for specific behavior.
Finally- it sounds like you still have some concerns that need addressing. 5 years old is young to be on medication but not completely unheard of. There may be some other issues that can be addressed. Also make sure your child's psychiatrist is willing to work with varying doses of stimulant medication. The idea is to keep going up incrementally as long as the ADHD behavior is still present and the side effects are not too unpleasant or risky.
I hope this helps. Don't despair, your pediatrician can find some local resources that will help you connect with some support groups. It's often very helpful to meet other parents who have gone through what you are going through!