I think the vet you are referring to is listed here:
http://www.englishforum.ch/pet-corne...et-thread.html
See Mrs. D's post for the vet in Dättwil..
If necessary, also call the Tierspital in Zürich, or the Spezialistenklinik in Zug. Both are listed in my post on the same thread.
Coughing can be a sign of many different conditions.
I have had two dogs who suffered from chronic bronchitis, one bacterial in origin, one idiopathic. Most episodes are not an emergency, and could be handled at home. However my girl, whose case was more severe and twice tipped into pneumonia, could reach a crisis stage where she needed an inhalation hood - which meant emergency visits to the Tierspital. My boy's episodes so far have not been emergencies, can wait for the vet's normal office hours, and usually respond to doxycycline.
How is your dog's breathing when resting?
If in any doubt, call the vet, or one of the two clinics mentioned - the vet on call will go through the symptoms your dog presents, and decide if the case warrants emergency treatment, or not.
ETA: When you call the vet, some questions likely to be asked:
How often does your dog cough? Try to keep a record.
What kind of cough - dry, hacking, throaty, with phlem?
Is he bringing up anythign when he coughs? If so, what?
When does he cough - during exercise, when lying down, when getting up from lying down, etc.
Is the wheezing constant, or does it come and go?
Is the wheezing a dry rattle, or does it sound moist?
Is the tiredness general lethargy, or is it exercise induced?
History of heart/respiratory problems?
When was he last wormed?
Any changes in appetite?
Paws crossed for your doglet - hope he starts to breathe easier soon. Do keep us updated.