Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that your pup is having some sort of choking episode, and I understand that you are concerned.
Do your pup's episodes look like this?
If they look like the video this is a "reverse sneeze" which is caused by irritation of the pharynx.
It can be from inhaled irritants (like any sort of pollen).
It can be related to gastroesophageal reflux.
It can be caused by excitement or post nasal drip or an overlong soft palate.
It can be secondary to irritation from a respiratory infection.
Dogs with dental and gum disease can have lots of inflammation and may be predisposed to post-nasal drip and reverse sneezing.
A reverse sneeze isn't harmful as it's just a spasm of the muscles around the pharynx because of the irritant, but it's no fun to watch. It can be stopped most times by rubbing the throat gently.
If it is because of gastroesophageal reflux then giving him an acid reducing medication may help. You can try either:
1) Pepcid-ac (famotidine) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 12 hours.
2) Prilosec (omeprazole) at a dose of one half of a 20mg tablet per 20 to 40 pounds of body weight every 24 hours.
These will reduce stomach acid and should help decrease symptoms related to reflux. These medications are quite safe and can be used long term if need be.
If it is related to an overlong soft palate then surgery may be required eventually if this is interfering with enjoyment of life or leading to breathing problems.
If your pup has a low grade respiratory infection or is exposed to cigarette smoke, candle or incense vapor, pollution or other irritants then that can be a possible complicating factor as well.
Ideally if this is worsening your pup needs to be re-evaluated by your family veterinarian. They can determine whether this is related to a an infection, reflux or an overlong soft palate. If you can take a video of one of his episodes they can conform that this is indeed a reverse sneeze.
In case this is related to a bacterial respiratory infection you should continue his prescribed antibiotics.
In the meantime I recommend making sure your pup does not get overheated or exercise too strenuously.
Because sometimes this can be related to dental or gum disease and the secondary inflammation from chronic infections. If this is the case a good cleaning should improve things tremendously.
You can also try putting him in the bathroom with you when you run a hot shower or bath. The steam soothes irritated airways and thins respiratory secretions, which should make him more comfortable and decrease the frequency and severity of his episodes.
Please let me know if you have any further questions.