What You Should Know About Antibiotics

As a mixed animal veterinarian in a rural community, it is not uncommon for me to get telephone calls from ranchers and horse clients about which antibiotics to give their large four legged critters.  Just as often they call and ask if it okay for them to give the same antibiotics to their farm dog.  I also field phone calls from small animal pet owners asking if they can give an antibiotic they have left over from either another pet or from their personal medical doctor, to another dog or cat.  It is easy for many to be casual about antibiotic use; they must be safe to use, after all you can buy them at your local farm and tractor store.  Antibiotics are powerful medications that require a level of understanding of pharmacology and bacteriology, and biology; something you should not trust your farm and ranch store assistant to supply. 

We live in a world where antibiotic resistance has been called one of the world's most pressing public health problems.  Almost every type of bacteria has become stronger and less responsive to antibiotic treatment when it is really needed.  These resistant bacteria can quickly spread from your animals to their human family members and to other human-human contact, threatening the household and the community with a new strain of infectious diseases that is more difficult to cure and more expensive to treat.  For this reason, antibiotic resistance is among the CDC's top concerns. 

Here are some things you should know:

1)  Sometimes Antibiotics aren't called for and may even cause harm.  As a veterinarian, unless I have evidence of a bacterial infection, I won't prescribe an antibiotic.  Antibiotics are only effective against bacteria, not viruses.  If your pet, horse or cow is suffering from a viral infection without  having a secondary bacterial infection, antibiotics have no benefit and only serves to increase the risk of bacterial resistance in the future. Giving unnecessary antibiotics can disrupt the animal's biological system and leave it vulnerable to other diseases.  Our society has come to seek out a quick fix for it's illnesses, expecting a 'pill' to fix all that ails us and our animals.  Sometimes it's just best to let mother nature run it course and allow the body to do it's work in protecting itself.  

2)  The antibiotic that worked so well for your pet/animal last time may not help him with his most current problem.  Just as true, the antibiotic that worked well for Fluffy may not help Fido, or Lightening the wonder horse.  Different antibiotics kill different bacteria, in different ways, with different potential side effects.  If Fido has a chronic condition such as renal failure, the enrofloxacin I prescribed for Fluffy's bladder infection could be harmful to Fido's kidneys, since it is an antibiotic known to be hard on the kidneys.  This holds true as well,  for left over antibiotics that you failed to finish taking yourself.  While it is true that many medications we use in veterinary medicine are also used for humans, your medical doctor intended you to take all your medication, not save some of it for your pet, just in case.  Failing to take all prescribed medications as directed leads to problems (addressed below).  Often your medication contain more milligrams than may be needed for your critter or may not be enough.  Either way only a veterinarian should be directing which drug is needed and in what concentration and for how long.

3)  Giving antibiotics at the prescribed dosage and time is vital to their effectiveness.  This means that if the doctor prescribes the medication to be given twice a day for 14 days, you should follow the directions.  The doctor knows how long the medication last within the body and will be trying to create a steady stream in the flood so that it is delivered at a constant rate to the bacteria.  

4)  YOU NEED TO GIVE THE ENTIRE COURSE OF THE ANTIBIOTIC even if your animal appears 'better' within the first few days.  Many times your doctor will prescribe an antibiotic for a two week course or even longer.  While you may think it unnecessary or excessive to give a medication after your pet/horse/cow appears healthy, it is crucial that you give the entire course of medication.  Not doing so contributes directly to antibiotic resistance that threatens your animal and you.  Why?  Simple genetics.  The bacteria killed early on are the susceptible ones--while the strong/clever ones are learning to adapt to the antibiotic action survive longer.  Stopping the medication before the stronger bacteria are killed off by the immune system leaves only these smart bugs behind to multiply in the face of the antibiotic and become more resistant to it.  When you fail to finish a course of antibiotics, for you or your pet, you are basically creating an environment conducive to a 'super race' of bacteria.  The infection may return and even be more aggressive than before.  Different antibiotics have different half-lives (how long they stay in the body) and are prescribed for different lengths of time based on the doctor's knowledge of the bacteria and the mechanism of the antibiotic.  These decisions are made based on experience, science and knowledge, not a random antibiotic for a length of time arbitrarily picked or simply to sell more medication.  

5)  If your animal is ill talk to your veterinarian.  If your animal is ill, take them to see your veterinarian.  In order to make a correct diagnosis and prescribe the correct medication your veterinarian will need to see you critter, even for chronic conditions.  We will not prescribe a medication without having the benefit of performing a physical examination and/or performing the necessary diagnostics needed to make a correct diagnosis in order to prescribe the correct medication.  Make no mistake, all medications are poisons, although helpful ones.  All medications have side effects of which we wish to keep at a minimum.  Proper use of these medications should be directed by your veterinarian and not the salesperson at the farm and ranch store.  

As a veterinarian, I am happy to practice medicine during a time when we have an arsenal of medications available to help in curing illnesses; compared to the old days when we used turpentine and arsenic!  We do however need to use these powerful medications judiciously and with full knowledge of their actions, side-effects and proper diagnosis.  Consult with your veterinarian before you reach for those left over medications from your medical doctor or head out to the feed store for a bottle of penicillin.  There is a reason that we are seeing more and more MRSA cases in human and animal medicine, let's not contribute to it.