I have done quite a bit of research on natural remedies for ADHD and behavioral solutions. You are right to be concerned about drugs. All drugs have side effects and some kids are more sensitive than others. What you need to know about drugs like Ritalin is that it makes some kids better and other kids a lot worse because it amplifies the symptoms. ADHD drugs have a long list of side effects and even side effects like loss of appetite and sleeplessness will have adverse effects on your child's growth and development.
A better, safer and more effective choice is a natural remedy which will calm the brain so that it can begin to heal itself. The best natural remedies for ADHD contain clinically proven ingredients and are FDA-approved. Look for ingredients like Hyocyamus and Arsen Iod.
Remedies help from a nutritional standpoint, but behavioral programs are also essential because they teach kids how to curb impulses and train their brains to focus, despite distractions. These programs can be used by parents at home and are a great way to create a deeper bond with your child by learning new skills together.
For kids who need to improve their focus, I recommend Total Focus which was developed by a therapist who wanted to help his own son with ADHD learn how to concentrate.
If your child is impulsive, disrespectful and defiant (and it sounds like this is the case), then you need to learn the skills that will help you teach him how to curb these impulses and treat others with respect. Teach him these skills when he's four, instead of having to do it when he's a big, strong teenager and is even more defiant than he is right now. This at home behavioral program was developed by a therapist who was once himself a troubled, angry, defiant kid.
The combination of a good natural remedy with a program that teaches coping skills is a highly effective, natural way to help a child with ADHD. Best of all, there are no worries about side effects or long term implications.