Some children with ADHD may exhibit side effects of the medication while taking it, especially when they first start taking it. Loss of appetite: This occurs mainly in the morning or midday, with most children regaining their appetite in the evening. Children on medication should be given a rich and sufficient amount of food each day, especially when their appetite is good (e.g., dinner) to supplement the nutrients needed for growth and development. Appetite-enhancing enzymes or herbal preparations may also be used. Taking the medication with breakfast or after a meal may reduce the side effects of decreased appetite, but may also be slightly less effective. Increased heart rate and blood pressure: Your child may experience a mild increase in heart rate and blood pressure while taking the medication, however, these changes are mild and do not pose any risk to most children. However, if your child already has high blood pressure, or has a family history of high blood pressure, you should tell your doctor so that he or she can be monitored appropriately when adjusting the dose of the medication. Insomnia: Some children fall asleep later than usual at night after taking the medication, especially children who take the medication late or in the afternoon. If there is severe difficulty falling asleep, the doctor should be told to adjust the dose of the medication or the time of day it is taken, or to combine it with some sleep improving medication. Neurotic tics: such as involuntary blinking, frowning, nose shrugging, etc., or short outbursts. Most often seen in children with previous twitching or a family history of twitching who are taking methylphenidate preparations. Sleepiness: Children taking tomoxetine may feel sleepy when they first start taking the drug or when the dose is increased, which usually decreases spontaneously in 1-2 weeks.