Topamate 25mg Tablet does not interfere with the working of valproic acid, but it increases the risk of getting excess levels of ammonia in the blood (hyperammonemia). Increased levels of ammonia in the blood can be dangerous and may cause difficulty in thinking, remembering information, or solving problems. It may also decrease your alertness and make you feel very sleepy with low energy. Immediately inform your doctor if you notice these symptoms. It is important to know that, in rare cases, Topamate 25mg Tablet alone can cause hyperammonemia.