Medication

i am not medical professional 

Its depends if this information is regarding your medication or your sons medication ? If you believe the medication is not benefiting and making things worse that i would go to person who prescribed the medication such as your doctor but with that in mind most doctors do not understand autism and adhd and the negative effects that some of these medications do and don't have on individuals with autism and adhd.

For any chance are you concerned because your son has been prescribed a medication that was never developed for individuals with autism spectrum disorder but more of an antipsychotic medication that fundamentally acting a sedative. Possible excuse for the medication is to reduce violent tendencies but from experience of being on this sort of medication is that it makes experience of an individual having the autism meltdown worse.    

There is no specific specialist but you can seek secondary consultation with another doctor who has knowledge of autism spectrum disorder or consult with a professional who specializes in autism. Most medical trials are published and accessible over the internet you just need to take the time to learn to read them properly.  

To be honest wih you a docotr or specialist in mental health could give the best advise. If the docotor understands your conditon and how the medication is affecting you then he should be able to make ammends and that for you while your on the medication or off it. 

Hope this helps you out abit !!!