Privine nasal drops typically only provide temporary relief from congestion due to the common cold or allergies. These drops work by narrowing the blood vessels in the nose area to reduce swelling and congestion, explains WebMD.
Privine nasal drops provide temporary relief for nasal congestion and can also treat symptoms such as blocked ears, notes WebMD. The drops sometimes help to reduce swelling in the nose before surgical procedures. If an individual uses Privine nasal drops for more than three days, "rebound congestion" can occur, causing symptoms to worsen. Those experiencing nasal congestion should consult a doctor if symptoms continue after three days.