Q. When your dog has a cold virus , how long does it take to go away when taking round of antibiotic?
DESTINI R. HOLLOWAY, DVM
A. Well this is actually a little bit more complicated of a question than most owners realize. "Colds" in people is similar to upper respiratory infections in dogs, they are usually caused by viral infections that can get secondary bacterial infections. If your dogs symptoms consist of mostly a "hacking cough" then the # 1 cause of this is "kennel cough" which is a bacterial infection only. However other things can cause a similar cough. But let's assume this is just a "Kennel cough" caused by Bordetella bronchiseptica, this is typically treated with a tetracycline drug such as Doxycycline for 10 days time. Most pets will be completely asymptomatic by day 4-7, however they can be infectious for up to 10 days after resolution of clinical signs.
If your pet is still hacking and coughing after 7-10 days of antibiotics then typically this means there is another underlying disease process or the bacterial infection is not susceptible to the antibiotic used. Another antibiotic can be tried at this point or your vet may suggest getting samples of the lung fluids (via a transtracheal wash or BAL) in order to correctly identify the source of the infection in order to select the appropriate treatment for it.