Hi, thanks for your query on Healthcare Magic I have read your description and understand your concern. It is okay to use both of these drugs at the same time, as there is no interaction found in their use. But keep in mind to always follow the instructions from a doctor about how to consume the druga. Hayfever itself can be prevented by avoiding triggers that can cause symptoms of hay fever, for example avoiding polluted environments or exposure to secondhand smoke. Allergens such as dust mites are hard to see and can multiply even in very clean homes, which is why it is difficult to avoid them. Hope this answer helps. Take care.