Hello, Sizodon plus is a combination of Risperidone and Tri hexyphenidyl. Pacitane also contains trihexyphenidyl. This is given to avoid side effects which can occur due to Risperidone. So if you are taking Sizodon plus then you might not need pacitane until you have any extra pyramidal side effects. The dosage is gradually increased till minimum effective dosage is reached. Its advisable to go for regular follow up to avoid relapse and keep a check on side effects.