The Cavy Corner: Antibiotics



	Living vicariously through guinea pigs since February, 1997

Antibiotics and Guinea Pigs

Any time a guinea pig is put on antibiotics, there is some element of risk involved. Even the "safe" varieties can have toxic effects, and as a general rule, they should only be prescribed when a bacterial infection has, or is suspected to have, taken place. This page describes what the risks are in putting a guinea pig on antibiotics, and how you can minimize those risks.

Important disclaimer: I am not a vet. Though this information was compiled from veterinary sources, it should not be considered a substitute for consulting with an exotics vet that is experienced in treating guinea pigs. You should always have your vet explain the risks involved in administering antibiotics to your cavy.

Why are antibiotics dangerous?

Guinea pigs primarily eat grasses and greens, and as such they have a sophisticated digestive system that depends upon bacteria. Both "good" and "bad" bacteria grow inside the guinea pig's digestive tract, and it is the "good" bacteria that aids in the digestion of their food. These bacteria are sensitive to antibiotics, because the primary purpose of an antibiotic is to kill bacteria. A large number of antibiotics are actually toxic to the guinea pig, and even the "safe" antibiotics can kill off the "good" bacteria in their digestive system, leading to diarrhea and other side effects, especially if administered in the wrong quantities.

When is it appropriate to use antibiotics?

You should only administer antibiotics when under the direction of a veterinarian that is experienced in the treatment of guinea pigs. They should be used when a bacterial infection has, or is suspected to have, taken place. Because of their inherint risks, they should never, ever be administered as a precaution.

Do not attempt to administer antibiotics without seeing a qualified vet first. The proper drug must be chosen for the situation, and your vet will need to calculate the required dosage based on your guinea pig's body weight.

Which antibiotics are toxic?

There are actually several antibiotics that are toxic to the guinea pig. The list provided below is neither comprehensive, nor complete.

amoxicillin
bacitracin
chlortetracycline
clindamycin
erythromycin
lincomycin
oxytetracycline
penicillin
streptomycin

A vet experienced in treating guinea pigs should never prescribe any of these medicines, and should be able to provide you with a more complete list.

How are antibiotics administered?

Antibiotics can be administered either orally, or by injection. Both methods have their pros and cons.

Orals

Oral antibiotics are typically in a suspension form that is flavored so that the guinea pig will willingly take them. They are measured out into an open syringe (a syringe without the needle), and the end of the syringe is place inside the guinea pig's mouth from the side (behind the front incisors). The antibiotic is then slowly injected into the guinea pig's mouth, so that he or she can lap it up as it comes out of the syringe.

Oral antibiotics are fairly easy to administer, provided the guinea pig likes the flavoring of the suspension, but they are very hard on the stomach and digestive tract, because the antibiotic directly comes into contact with the bacteria in their digestive system.

Injections

Injections can be done at home if you have your vet show you the proper technique. Most antibiotics can be injected into muscle tissue, and many vets recommend that you choose the rear leg muscles, which are large and soft. Guinea pig skin is rather thick, so a proper injection requires that you pop the needle in with a jabbing motion. Once it is in, you can inject the antibiotic very quickly, and pull the needle out right away. Most guinea pigs will squeal when the needle is inserted, and again when it's pulled out, but will be fine immediately afterwards.

Administering antibiotics by injection is easier on the guinea pig's digestive system, since the antibiotics don't come into direct contact with the bacteria in the digestive tract. However, they usually present more of a problem for the owner, who may be squeamish at the idea of sticking a needle in their pet. It is helpful to cover the guinea pig's head with a towel, so that he or she can't see what you are doing (otherwise, the cavy might squirm or try to get away, and you could end up injuring him or her with the needle).

What should I watch for while my guinea pig is on antibiotics?

Even the "safe" antibiotics can have toxic effects on guinea pigs, particularly if the guinea pig is in a stressful situation. If your guinea pig experiences any of the following symptoms, contact your vet immediately, and discontinue use of the drug:

diarrhea
depression
listlessness/lethargy
loss of appetite

Your vet should also provide you with other side-effects that you should watch for.

What precautions can I take to minimize the risks?

There are several things that you should do while your guinea pig is under going treatment via antibiotics:

Lactobacilli acidophilus supplements

Acidophilus is a non-dairy based bacteria-growing culture that enables the growth of the lactobacillus bacteria that aid in digestion. Acidophilus is available at pharmacies and health-food stores, and comes in a capsule or liquid form. The liquid form has short shelf-life (only a few weeks), so the capsule form is generally recommended, as it can last for months if stored in the refrigerator.

Administer the acidophilus by dissolving the powder of half of a capsule in about 1 cc of water, in an open syringe. Administer the acidophilus orally, from the syringe, just as described for oral antibiotics, above.

If you use oral antibiotics, you should wait at least one hour after administering the acidophilus before giving the antibiotic. Otherwise, the acidophilus will still be in the digestive system, and the antibiotic will kill off the bacteria that the acidophilus is culturing before they have had a chance to build up. If you are administering antibiotics via injections, you do not need to wait.

Acidophilus supplements will reduce the risks of diarrhea, by giving the "good" bacteria in the digestive system the opportunity to build up before the antibiotic hits.

Feed lots of timothy hay

Timothy hay, and other grass hays, are high in fiber, which are essential for keeping your guinea pig's digestive system balanced. When on antibiotics, it is even more critical that your guinea pig have access to as much timothy hay as he or she will eat. Avoid legume hays (such as alfalfa) during the treatment.

Maintain a stress-free environment

Stress and antibiotics are a dangerous combination. Whenever possible, minize any changes in the guinea pig's daily routine. This means:

Keep their diet consistent, and don't introduce any new foods.
Don't change their environment. Don't put them in a new room, house them with new, strange guinea pigs or move them around a lot.
Make sure the temperature in their room is fairly constant and warm. Give them plenty of hay for insulation.

There is no guarantee that, if you follow all of these precautions, your guinea pig will always survive their antibiotic treatment without incident, but it does minimize the risks. As always, contact your vet if you suspect any problems.

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