I take the Carbocisteine 3 tablets three times daily which is the max amount but also find that using a nebuliser with a saline solution 2 or 3 times daily also helps a great deal,
many of us are prescribed Carbocysteine to help soften mucus making it easier to expel from the lungs. Drinking plenty of fluids also helps hydrate the whole system.
In other parts of Europe Nac- Acetylcysteine is prescribed (can be purchased in England, I dont know about the rest of UK)
Both are known as mucolytics (Nac is used for other health benefits but i cant remember what). Try using the search bar, you'll find lots of information. P