Yes, Sinomet S Nasal Spray is generally safe for prolonged use, as it contains a saline solution (sodium chloride) that helps to moisturise and clear the nasal passages. It does not cause dependence or rebound congestion like some medicated sprays. You can use it regularly for dryness, allergies, or sinus care. However, if you need to use it frequently for ongoing symptoms, it is advisable to consult your doctor to rule out any underlying condition.