Hi Welcome I have gone thru your query regarding side effects of Decdan . Dear I can understand your concern for your health . it can cause immune suppression, weight gain and fluid retention. With improper use, both the immune suppression and the fluid retention can put you in serious medical danger . As per studies show , Decdan (Dexamethasone) may cause withdrawal symptoms if you were to suddenly stop taking abruptly. So if you want to avoid such symptoms or at least lessen the severity of them, I would encourage you speak with your doctor about setting up a tapering plan in order to make it an easier transition. And concerning weight gain, it sounds to me like your best bet would be to focus on making changes to your regular diet containing all essential nutrients and regular exercise ,Walk , Yoga , Pranayam & Meditation to increase immunity . Since this is the foundation for body building - not necessarily referring to body-builders who compete, but building up your body is essentially what you d be doing by gaining weight. Proper nutrition and regular exercise are key! Avoid processed foods carbs , sugar , fried ,fast foods , Tea , coffee ,alcohol and smoking , stress and Constipation all will produce biochemical and metabolic conditions in your body that will decrease your immunity, so avoiding is definitely the first step in the right direction to detoxing the body to boosting the immune system . All are the pillers of our strong immune system responsible for healthy disease free life Always remember, to see your doctor / professional for proper guidance Hope this helps solves your query .Take care .All the best .Get well soon Don t hesitate to come back in case of any further query .