Recently I had a surprising elimination of a post nasal drip. I've dealt with them for 20+ yrs. I take serrapeptase intermittently but had not taken it for months. Then a few weeks ago I had a bad bout. Was miserable. I had just bought Zinc & elderberry lozenges and that night, after waking up coughing, reached for them and popped one in my mouth and went back to sleep. When I woke, it was the strangest feeling in my throat/sinus area; dry like the Sahara feeling. The drip was gone. The strange feeling remained for 2-3 days but it was almost miraculous how it stopped the PND. Maybe bc I was laying down it was able to directly affect the area, as opposed to being upright. I don't know other than it was an extremely surprising & welcomed effect!
For chronic cases (which I no longer have) I highly recommend Grapefruit Seed Extract (aka 'GSE'). The root cause of sinus infections and PND is mold and fungus. A recent study of chronic sinusitis and fungus done by the mayo clinic found that a whopping 97% of people tested had an average of 2.7 types of fungus growing in their sinus cavities. And they were successfully treated for chronic sinus infections using antifungal medications treatments. But what was found to be the most effective antifungal agent, by far, was the natural remedy of grapefruit seed extract (GSE)! ... Same goes for most respiratory infections.
I got home from the hospital from pneumonia and was not OK. Started immediately, I got empty capsules and filled them up 15-20 drops of extract fit in each cap (30 drops, twice daily). Amazing remedy! I've read ppl opening nasal spray bottles of saline solution and adding a 3 drops of GSE and spraying that into their sinuses every 3-4 times daily. Our medicine cabinet won't be without this. Research it for yourself. And lastly, buy the GSE that's been around forever (red label & cap), not the newer ones that I hear are not as potent.