Hello You were taking Xet C R with reduced dosage from 25 mg to 12.5 mg . Now completely stopped the drug abruptly , although this was not a good step but any how , now you are perfectly alright . You are not feeling any untoward effect , that is a good thing. This is PAROXETINE and an anti depressant drug and most effective drug . In your case you were taking it for panic disorder . It is very difficult to say whether you will require it in future or not , it all depend on condition and circumstances of you. I recommend you , if feel any panic disorder take it in low dosage and try to maintain the condition , if necessary gradually increase the dosage in future. As far as concerned about the side effects , these are minor as in comparison its benefit specially for you. Side effects are;Somnolence , insomnia , headache, dizziness, decrease libido, diarrhea, ejaculatory disturbance ,weakness , tremor, diaphoresis , chest pain, palpitation, yawing, abdominal discomfort. Nothing like any serious life threatening , so you can use it safely for long time , if desired. Hope this will help you.