Hi, Zen Retard contains carbamazepine which belongs to the group of medications known as anticonvulsants is used to treat epilepsy. It helps prevent certain types of seizures or fits. It is also prescribed for a painful condition of the head, face and neck known as trigeminal neuralgia and diabetes related nerve pain. Serum lipid levels change during carbamazepine medications like Zen Retard. The increase in serum concentrations of total cholesterol and high density lipoprotein cholesterol seems parmanent, but the increase in serum low density lipoprotein cholesterol and triglyceride levels are transient after 3 months use of treatment with carbamazepine like Zen Retard. Again, the patients have received the carbamazepine like Zen Retard as anticonvulsant treatment and soon after starting the drug, abruptly developed an increase in appetite with a concomitant increase in food intake. Thus helps to gain weight rapidly. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician