My son is 21 years old and weighs over 75 kilos, he has been taki...

My son is 21 years old and weighs over 75 kilos, he has been taking melleril for over 5 years now, initially taking 2 a day (each of 100mg). It's ben a few years now that i've been giving him only one tablet but now 1 tablet is doing him absolutely nothing, I am now trying him with 2 tablets and finding that he is still agressive. Would it be safe for me to give him 3 tablets a day. I was thinking maybe to give him 2 in the morning and 1 in the afternoon. I have to come to a solution about this as he is biting me more each day and becoming more dangerous each day....Please help me...DONNA