THE PET HEALTH LIBRARY By Wendy C. Brooks, DVM, DipABVP Educational Director, VeterinaryPartner.com

(for veterinary information only) 

Brand Name: Tamiflu  

Available in 75 mg capsules oral suspension 

canine parvovirus image courtesy of JY Sgro, UW-Madison

The virus has no protein metabolism or other systems that a medication might target. A virus simply acts like a syringe that attaches to a host cell, injects its genetic material inside, and tricks the host cell into transcribing this material. In other words, it injects its own DNA into the host cell, and attaches its own DNA to the host's DNA. The viral DNA instructs the cell to stop what it is doing and start mass-producing more virus. Soon the host cell becomes a virus factory, and replicates thousands of new viral organisms that go forward and infect new cells.    

Viruses are responsible for herpes, influenza, HIV, the common cold, and numerous other infections with which we are familiar. It has only been relatively recently that we have had the technology to attack viral biology. Oseltamivir represents such an effort.   

Oseltamivir specifically targets the influenza virus. This virus has an attachment enzyme on its surface called neuraminidase. This enzyme allows the flu virus to bud from the host cell in which it was created and then happily pass through the mucus of the respiratory tract to any cell in the tract it wishes to infect. Inhibiting neuraminidase effectively locks the new viral organisms within their host cell, imprisoning them so that they cannot infect new cells. The immune system will recognize the infected cell and kill it along with its infective contents. Oseltamivir is felt to cut a couple of days out of one’s sickness period when it comes to the flu.    

All this, of course, has virtually nothing to do with pets.  

Recently, veterinary interest has turned to oseltamivir in the treatment of canine parvovirus, a life-threatening infection characterized by vomiting and bloody diarrhea. The jury is still out on how well oseltamivir treats parvovirus, although many feel it represents a breakthrough.   

How this Medication is Used   

To assist in the treatment of canine parvovirus infection, oseltamivir is given orally twice a day for 5 days. The medication should be obtained as soon as the parvovirus diagnosis is confirmed. If a puppy has been exposed to canine parvovirus but is not ill, oftentimes the clinical disease can be circumvented by giving a course of oseltamivir.   

Usually an oral suspension is compounded or the human product is given. This medication is not approved for use in animals.   

Side Effects   

In pets, side effects have not been appreciated; however, veterinary experience is limited but the following is taken from human patient information sheets on oseltamivir. 

Side effects that you should report to your prescriber or healthcare professional as soon as possible:   

• difficulty breathing or shortness of breath  
• ear ache or infection  
• infection and inflammation of the sinuses (nose) and chest  
• skin rash    

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):   

• coughing  
• diarrhea  
• difficulty sleeping  
• dizziness  
• headache  
• nausea and vomiting  
• nose bleed  

There are no known drug interactions with oseltamivir.   

Concerns and Cautions   

The most important caution is to recognize that canine parvovirus is a life-threatening infection for which there is no substitute for hospitalization. You should never attempt to diagnose parvovirus infection on your own nor treat it without veterinary supervision. Puppies that have advanced parvo symptoms such as septicemia or severe dehydration may not respond to oseltamivir. This medication works best early in the course of infection before the patient is combating large amounts of virus. Remember, the goal of using oseltamivir is to minimize the amount of virus in the patient so that the immune system will have an easier job eradicating the infected cells.

Reconstituted oseltamivir does not last longer than 10 days and must be disposed of afterwards.   

If a patient seems to have an upset stomach on oseltamivir, give the medication with food to mitigate the effect.

It is our policy not to give dosing information over the Internet.

Date Published: 1/24/2005 10:29:00 AM
Date Reviewed/Revised: 02/05/2010