As he is taking 20 mg of Methylphenidate and his dose may be adjusted in weekly 10 mg increment to 54mg.
So his medication dosage may increase from 20 to 30 mg in first week and then 30 40 40 in second week and 40-50 mg in third week.
If his medication dosage is given twice a day then his dosage may increase from 20-40 mg in first week and then 40-54 mg in second week.
Having said this,firstly you need to ask his doctor for dose management to prevent any adverse effects.
I hope this helps.
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