by Debbie “The Rat Lady” Ducommun
updated
This article is from my booklet Rat Health Care. I highly recommend you order a copy to have on hand! Check it out at Rat Books
Respiratory disease is the most common health problem and cause of death in pet rats. The most common organism causing this disease in rats is the bacteria Mycoplasma pulmonis, which can enter the body’s cells in order to hide from antibiotics. While antibiotic treatment can help control the disease, there is no known cure for rats.
Mycoplasmosis is extremely contagious and
baby rats contract the bacteria from their mother during birth. The disease has become so common that pretty
much all pet rats are infected, whether they have symptoms or not. Laboratory rats are free of the disease
because in the past, baby rats were delivered by Caesarian section while the
mother was submerged in disinfectant, sacrificing the mother. All laboratory rats in the world are now
descended from these hand-fed babies.
The Mycoplasma bacteria live in the lungs, therefore it is incorrect to refer to “upper respiratory infections (URI)” in rats. Mycoplasma commonly causes pneumonia, lung abscesses, emphysema and lung lesions which on autopsy can appear as a “cobblestone” effect on the surface of the lungs. It can also cause inflammation and bleeding of the uterus. To see autopsy pictures of rat lungs click here.
A mycoplasma infection makes a rat more susceptible to secondary respiratory bacterial infections as well. The respiratory symptoms that are common in rats can be caused either by the primary mycoplasma infection, secondary infections, or both as well as heart disease. In young rats, symptoms are more likely to be caused by secondary infection, so they need to be treated accordingly. To see autopsy pictures of rat hearts, click here.
Most respiratory symptoms in rats are caused by respiratory infections or heart disease. It is very rare to find a lung tumor in rats. Since 1985 years I have done gross autopsies on more than 200 rats and I have only seen two lung tumors.
Since mycoplasma is so prevalent, you should assume all rats outside the lab have it. However, if you want to test rats for mycoplasma or other respiratory diseases, the best test is a blood test called a serology ELISA test, because mycoplasma is very difficult to culture, often resulting in a false negative. Charles River Labs, 1-800-LABRATS, will perform serology testing on rat blood. The myco test is $11.75.
Different rats also seem to have differing resistance to the disease. The severity of a mycoplasma infection can be increased by cigarette smoke, ammonia from a dirty cage, vitamin A or E deficiency, pine or cedar shavings, and a concurrent respiratory infection of another type, as well as genetic susceptibility.
(None of the organisms causing respiratory
infections in rats are infectious to humans. The only diseases I know of that can be
transmitted from domestic rats to humans are salmonella and “rat-bite fever,” a rare
bacterial infection similar to cat-scratch fever. For more info see my article at ratfanclub.org/ratbitefever.html.)
Common Symptoms
The first symptom of a respiratory infection is usually frequent sneezing
(healthy rats rarely sneeze) which can progress to wheezing. To hear examples of rats wheezing, click
here. Often,
the first symptoms of respiratory disease seen in a rat, especially in young
rats, will be caused by a secondary infection. Mycoplasmosis tends to be a slowly
progressive chronic disease that usually doesn’t cause symptoms until the
rat is older than 8 months of age.
For any symptoms, I recommend first trying amoxicillin, which tends to
work well for secondary infections.
Secondary infections can become more serious more quickly than
mycoplasma, so treat for them first.
If you treat for mycoplasma first, and it turns out to be a secondary
infection, the rat may get so sick he dies before you can try the treatment for
secondary infections. Usually a
mycoplasma infection is chronic, that is, it starts out slowly with mild
symptoms that gradually get worse over a period of weeks or months, so quick
treatment for myco is not as critical as it is for a secondary infection. I recommend that all rats owners have
amoxicillin on hand so sick rats can be treated ASAP.
When treating respiratory symptoms in rats with amoxicillin, if the symptoms do not improve within 3 days of treatment, then you should switch to doxycycline, which tends to work well for mycoplasma.
Symptoms of advanced lung or heart disease
can include labored breathing, weight loss, blue extremities, and respiratory
distress, which can cause a rat to gasp through her mouth or become agitated
and dash about in panic. For the
treatment of respiratory distress, see the article on First Aid. If treatment cannot prevent such
attacks, euthanasia is the kindest action.
Mycoplasma usually causes only respiratory
symptoms. Other symptoms such as loss
of appetite, lethargy, rough coat, and hunched posture are usually caused
by a secondary infection or other disease, and should be treated immediately
with amoxicillin. A rat who is
extremely lethargic and refuses to eat or drink needs amoxicillin
force-fed.
An infection can also damage the nasal cavity resulting in bleeding,
which can be fatal. Nasal infections are difficult to cure and should be
treated long-term with amoxicillin.
(For how to mix and use amoxicillin see “Giving Medications” and “Mixing Medications in a Liquid” below.)
Secondary
Infections
Mycoplasma makes rats more susceptible to
secondary bacterial infections from a variety of bacteria. These infections are usually
opportunistic, taking advantage of a break in the immune system, and are not
usually contagious.
If a rat appears quite ill, then it
is a good idea to give both amoxicillin and enrofloxacin at the same time. Both are bacteriocidal and work well
together. Amoxicillin can also be
used in combination with doxycycline, because they work on different
bacteria. Another good combination
for severe symptoms is gentamicin and amoxicillin. Both of these combinations target
secondary infections as well as mycoplasma. I recommend treating secondary
infections for a minimum of 2-3 weeks or until symptoms have been gone at least
a week.
There is controversy whether rats can get
strep from a human with strep throat.
The organisms are supposed to be different (Streptococcus pyogenes
for strep throat, Streptococcus pneumoniae for rats) but there have been
some suspicious cases. It is
probably best for someone with strep throat to avoid rats.
Some books say that rats can get “colds,”
but they mean respiratory infections.
Rats cannot get the human cold or flu.
Viral
Infections
There are two viruses that can cause
respiratory symptoms in rats.
Sendai virus causes a true respiratory infection. Sialodacryoadenitis (SDA) virus is an
infection of the salivary glands, and symptoms can include sneezing, wheezing,
runny eyes and nose, labored breathing, swelling of the glands under the
throat, bulging eyes and sudden death.
In mycoplasma-free lab rats these viruses
are not usually fatal to post-weaning rats and the rats recover in a week or
two. (Sendai can cause a stuffy
nose in infants which can prevent nursing and cause death.) However, for rats infected with
mycoplasma, a viral infection can result in fatal secondary infections. In fact, the first indication that a rat
colony has been infected with a virus can be the sudden death of one or two
rats. The disease is usually more
severe in older rats.
You can’t treat the virus, but you
can treat the secondary infections that cause the most danger. Sometimes treatment with amoxicillin
and/or enrofloxacin is enough, and sometimes gentamicin with either amoxicillin
or cefadroxil is necessary.
Aggressive supportive therapy, including fluids, and dexametha- sone for
inflammation, might be necessary. Treatment with ophthalmic ointment may be
necessary to prevent eye damage.
Both viruses will die out in a population
within 60 days if there are no new rats or babies. Charles Rivers Laboratories says the SDA
virus is only shed for 7 days, but an infected rat will usually have antibodies
to the virus for the rest of her life.
Disease
Transmission & Quarantine
Most pet rats get mycoplasma directly from
their mother during birth and so have it all their lives. Infected rats can transmit the disease
to mycoplasma-free rats (lab rats) through direct contact or repeated exposure
through the air.
The rat viruses and some secondary bacteria
can be spread both through direct contact and through the air. Apparently, the SDA virus can live for 3
hours on inanimate objects, and longer in the human nasal tract, so after being
around strange rats it is best to blow your nose and wait 3 hours before going
home or visiting other rats.
To protect your rats from the viruses, it
is always a good idea for new rats or rats returning from a show to be
quarantined for at least 1-2 weeks before exposing them to your other
rats. Ideally there should be no
air-flow between your rats’ room and the quarantine area. Wash thoroughly and change your clothes
after being with the quarantined rats.
Other
Causes of Respiratory Symptoms
Some rats are sensitive to some
beddings—most commonly CareFRESH—and can sneeze when exposed to
them. Pine and cedar shavings, which are toxic, can cause sneezing. Allergies are rare, but can occur. I know of a rat who wheezed in response
to yogurt drops, and 2 brothers who sneezed when exposed to dogs! The most common foods to cause allergies
in rats are peanuts and dairy products, including yogurt drops.
Congestive heart failure, which is also very
common in rats, can also cause respiratory symptoms. Lung tumors are very
rare. Since 1985 I have done gross
autopsies on more than 250 rats and I have seen only 2 lung tumors, although I have seen 4 chest lymphomas.
Inner
Ear Infections
Inner ear infections are common in
rats. They may be caused by
mycoplasma or a secondary bacteria such as Streptococcus moniliformis or
Pseudomonas. The infection
causes inflammation in the inner ear, affecting the rat’s balance. This will cause the rat to hold his head
tilted to one side. This is why
some books call this disease “wry neck” but it has nothing to do
with the neck. Without treatment,
the loss of balance can get so bad the rat will roll over and over and is
unable to eat. An inner ear infection can result in a permanent head tilt,
especially if the symptoms are untreated.
An inner ear infection can also cause facial paralysis (see page 41 in
my Rat Health Care booklet.)
An inner ear infection requires immediate
treatment. I recommend using either
enrofloxacin and amoxicillin together, or chloremphenicol. An anti-inflammatory,
either a steroid or an NSAID, must also be given to reduce the swelling in
the ear. Prednisone can
be given at 1 mg/lb twice a day or ibuprofen at 15-60 mg/lb 2 to 4 times a day.
Another NSAID that can be use for
inflammation in rat is Metacam.
Metacam is a brand name and the generic name is meloxicam. The liquid
sold by vets is for dogs, and since dogs do not metabolize NSAIDs well, the dog
dose is very low (only 0.1 mg/lb). Rats metabolize NSAIDs very well.
(That’s why the dose of ibuprofen for inflammation in rats is 15-60 mg/lb
2 to 4 times a day.) By comparing
the human dose of ibuprofen to that for rats, and then looking at the human dose
of meloxicam (which is 7.5 to 15 mg a day), it appears that the best dose of
Metacam for rats is 1 to 2.25 mg/lb. Since the usual concentration of the
Metacam liquid is 1.5 mg/ml, a 1-lb rat would need 0.6 to 1.5 ml. In addition,
although meloxicam is only given once a day to humans and dogs, because the
rat’s metabolism is so much higher, it might need to be given more often
to rats. I recently talked with a rat owner giving Metacam to a rat with severe
pain, and she reports that once a day does not seem often enough.
Other possible causes of a head tilt are a
pituitary tumor or stroke, but the treatment for either is the same as for an
inner ear infection.
Treating
Mycoplasma
The antibiotics that tend to be effective
against mycoplasma include (in general order of most to least effective)
gentamicin, enrofloxacin, doxycycline, chloremphenical, clarithro- mycin,
azithromycin, tylosin, tetracycline, and erythromycin. There are different strains of
mycoplasma that are more or less resistant to various antibiotics.
Because mycoplasma is a very resistant
organism, treatment must be persistent.
Humans can contract a version of mycoplasma which is a different disease
than what rats get (humans get Mycoplasma pneumoniae) and when they do
the treatment is antibiotics for 1-2 years!
I recommend treating mycoplasma for at
least 6-12 weeks at a time or even much longer. An older rat with chronic symptoms
and/or heart disease should be on enrofloxacin and/or doxycycline for
the rest of his life. Both these antibiotics are usually
well tolerated by rats for long periods of time. I have had some of my rats on
enrofloxacin or doxycycline for over a year with good results, and one of my
vet’s patients lived to be over 4 years old and was on Baytril the last 2
years of her life!
Other
Respiratory Medications
If your rat’s nose seems congested,
the decongestant pseudephedrine might help (use carefully in rats with
congestive heart failure). Buy the
non-drowsy pediatric formula. A product also containing guivesan seems to dry
them out less. An antihistamine can
be helpful in some cases, and especially, of course, if the symptoms are caused
by an allergy. But remember these
only treat the symptoms, not the cause.
A bronchodialator
can be very helpful in rats with labored breathing or respiratory
distress. The one I use the most is
aminophylline, but I have also used theophylline for a rat who hated the taste
of aminophylline. Aminophylline can
be given either orally for long-term treatment or by injection in an emergency.
The dose for aminophylline is 1.36mg/lb twice a day. Primatene (ephedrine) is a
bronchodialator available over the counter. You can buy a Primatene Mist inhaler to
have on hand for emergency treatment of respiratory distress. (See page First
Aid.) If your pharmacy
doesn’t carry it you can get it mail order. You can also try the oral
form of Primatene at 1 mg/lb
twice a day.
An anti-inflammatory can also
be very helpful to reduce inflammation in the lungs. Ibuprofen has been helpful in several cases,
and I use prednisone extensively.
The dose for prednisone is 1 mg/lb twice a day. For severe acute infections, an injection
of dexaphosphate or dexamethasone are stronger. You should see improvement within 12
hours.
If there is excess fluid in the lungs, a diuretic can be helpful. I’ve had good results with Lasix (furosemide) at a dose of 1-2 mg/lb 1-3 times/day. You should see improvement with oral dosing within 12 hours, and with an injection in a few hours. Vitamin B6 can also act as a diuretic. I suggest trying 5-10 mg per day. When a rat is on a diuretic, you must frequently check him for dehydration by pinching the skin on his back. In a rat who is normally hydrated, the skin will snap back immediately. The longer the skin takes to snap back, the more dehydrated a rat is. If a rat on a diuretic becomes dehydrated you must stop the diuretic and get the rat rehydrated.
I have found that rats with advanced respiratory disease often have congestive heart failure as well. The recommended treatment for heart failure is a low sodium diet, enalapril (dose 0.25 mg/lb twice a day), which lowers the blood pressure and makes it easier for the heart to beat, and atenolol (1 mg/lb twice a day), an beta-blocker that slows the heartbeat to make it more effective. (The American Heart Association recently announced it was recommending the use of beta-blockers for most patients with congestive heart failure.) Enalapril is so safe it can be used as a diagnostic tool. If giving enalapril makes the rat feel better, then you know he has congestive heart failure. If enalapril is going to help you should see improvement in the rat’s symptoms within 5 days. A diuretic can also help in some cases. For more information about congestive heart failure, see my Rat Health Care booklet.
Other
Treatments
Moisturizing the air with a humidifier will
help your rat breathe more easily.
A product called VetRx or FerretRx can help
in some cases. It is aromatherapy
that works by stimulating deeper breathing and contains Canada balsam, camphor,
oil origanum, and oil Rosemary. The
best results seem to come by putting a few drops in the nest box or on the
bedding where it will be inhaled 2-3 times a day. Do not rub it on your rat’s nose
as this seems to cause discomfort for some rats. When using it, try alternating one week
on, one week off. It seems to cause
irritation if used continuously.
Look for these product in pet shops and feed stores. Another essential
oil that can help is eucalyptus, or you can use Vicks Vaporub.
If a rat is having gasping attacks, he will
swallow large quantities of air which he can’t burp up. This will cause stomach distension and
discomfort. In severe cases it can press
on the chest and make the breathing worse, so the air must be removed from the
stomach through needle aspiration.
If the rat is no longer gasping (a rat in
respiratory distress will not be able to take oral medications) but still has a
distended stomach, you can try using the product Gas-X. Try giving about ¼ teaspoon.
When a rat is experiencing severe labored
breathing or respiratory distress, oxygen therapy can be beneficial. It can make the rat more comfortable
while you wait for medications to work.
Gas oxygen must be prescribed by your vet. You can rent or buy bottled oxygen, and
you can also buy a machine that concentrates oxygen out of the air. Used oxygen concentrators are sold on
eBay without a prescription for around $200-300. You can use a 10-gallon aquarium as an
oxygen chamber, or make a chamber as for nebulizer treatments (see below). The rat will need to live in the chamber
until other treatments insure comfort outside the chamber. Don’t forget a water bottle.
If respiratory symptoms do not improve in
an oxygen chamber, it means the lungs are not capable of oxygen exchange, and
the rat should be immediately euthanized.
Aggressive
Treatment
You can significantly improve the health
and life span of most rats with respiratory disease by treating all symptoms
promptly, continuing antibiotics for the treatment periods I’ve
recommended, and trying new medications if one is not working. Treatment for
heart disease is also important.
Even if your rat becomes very sick,
don’t give up. I’ve seen several rats pulled back from the brink of
death after receiving the correct medications, recovering their health to live
for several more months. Although
respiratory and heart disease are extremely common and can be devastating,
prompt and persistent treatment with medications that work for your rat can
help keep the diseases in check in most cases, and will usually allow your rat
to enjoy a long happy life.
Giving Medications
For tablets, you can grind them up into a fine powder on a small plate with a spoon. You can then mix the powder in liquid or food. Or, you can let tablets dissolve in liquid overnight. Some suggestions for foods to put medications into include baby food, pudding, mashed avocado, yogurt, brown sugar and carob powder, honey, peanutbutter mixed with jelly, moistened graham cracker, non-fat cream cheese, margarine, Nutri-Cal, pasta sauce, and as a last resort, ice cream, frosting, cheesecake, or even butterscotch or chocolate syrup! Use only enough food to mask the taste of the medicine so your rat will eat it all immediately. Adding a bit of salt will help counter the bitter flavor of medicines. If your rat refuses to eat the doctored food voluntarily, those in paste form can be smeared on his mouth, or even on the backs of his ears so he will groom the paste off and eat it.
The dose for ibuprofen is 15-60 mg/lb 2 to 4 times a day. You can use you can either crush up a tablet or use liquid baby medications if they do not contain sorbitol, an artificial sweetener that rats hate. Sorbitol will be listed under the inactive ingredients. Most rats like berry flavored Motrin. To figure out the dose, look on the bottle to see how many mg/ml. Figure out how many ml to use to give your rat the proper number of mg. It’s a good idea to give the rat a treat afterwards to mask the bad aftertaste that may cause your rat to refuse the medication the second time.
Antibiotic Treatment
Antibiotics are different from other drugs in that they don’t work
directly on the patient; instead they work on bacteria inside the
patient’s body. In general,
it is better to give a higher dose rather than too little. Antibiotics must be selected carefully not
only according to what type of bacteria may be causing the infection, but also
how the antibiotic works, what tissues of the body it can penetrate, the
patient’s state of health, and any possible side-effects.
Antibiotics are divided into two groups according to how they
work. Bactericidal antibiotics
actually kill the bacteria but only when they are growing. Bacteriostatic antibiotics prevent the
bacteria from growing, so the immune system can kill them off. Bacteriocidal types should be used for
serious acute infections whenever possible.
Some antibiotics have a synergistic effect, having a greater effect
together than when used alone. This
occurs when gentamicin is used with the penicillins, which assist gentamicin in
penetrating the bacteria’s cell wall.
Bacterial
Resistance
There is some confusion about resistance to antibiotics. It’s not the patient that develops
a resistance to an antibiotic, it is the bacteria. A particular type of bacteria might
develop a way to withstand the action of an antibiotic. This is more likely to happen when the
antibiotic is only given for a short period of time, if it is given off and on,
or if it is given at a less than optimum dose. The bacteria might be able to withstand
a short weak attack but not a longer stronger attack. This is why when treating respiratory
infections in rats it’s not a good idea to give an antibiotic for
mycoplasma for less than 6 weeks,
or to use antibiotics in a on-off, on-off fashion. It’s better to use the antibiotic
steadily for a long time. If
bacteria become resistant to an antibiotic, then a different antibiotic must be
used. Using two antibiotics
together can sometimes also overcome resistance.
Using
Antibiotics
If a particular antibiotic is effective against an infectious organism,
you should see an improvement in acute symptoms within 2-3 days, or in
chronic symptoms in 3-5 days.
Don’t keep using the same treatment if there is no
improvement in the symptoms! With any treatment you should continue to
see steady improvement in the symptoms.
If you don’t, try another antibiotic. (See Flowcharts on page 26-28 of my Rat Health Care booklet.) If the symptoms come back, restart
the treatment and continue it at least twice as long.
When a rat is severely ill, it is a good idea for the first dose given
to be extra strong, sometimes twice the normal dose, to get the patient off to
a good start. In general, the length of treatment for infections affecting the
skin should be at least 10-14 days.
Respiratory and urinary infections generally need to be treated for several
weeks.
I recommend continuing treatment for secondary respiratory
infections for at least 2-3 weeks, or until the symptoms have been gone for
at least a week. In cases of
chronic respiratory infections, treatment can and should be continued for
longer than this. However, some
antibiotics, such as gentamicin and chloremphenicol should not be used longer
than 14 days. For mycoplasma
the course of treatment should be at least 6-12 weeks and sometimes
for the rest of the rat’s life.
Most Useful
Antibiotics
I have found the most useful antibiotics for rats to be amoxicillin,
doxycycline and enrofloxacin (Baytril).
For the past 10 years or so I have hardly used anything else. I find that respiratory symptoms that
don’t respond to these antibiotics are usually caused by congestive heart
failure.
amoxicillin
Amoxicillin is a
broad spectrum antibiotic in the penicillin family. It is bacteriocidal. Although it is not
effective against Mycoplasma, it is the best choice for secondary
infections, and the first antibiotic I always recommend
trying. Even if a rat is on
doxycycline or enrofloxacin for mycoplasma, if he develops symptoms of a
secondary infection (see page 24), he should be put on amoxicillin in
addition to the other antibiotic. It is also the best antibiotic for
abscesses and skin infections, and can be good for urinary infections,
especially along with Baytril.
Amoxicillin has a wide dose range of 10-50 mg/lb BID1. Ten mg/lb is the standard dose, but
higher doses can be tried in severe cases, or if the lower dose doesn’t
seem to be working well. It should
be given for at least 2-3 weeks, but can be used long-term without problems in
most rats. It can cause diarrhea in
some rats. Mild diarrhea can be
treated with probiotics, but if it is severe, the amoxicillin should probably
be stopped.
The most common brand prescribed by veterinarians is Amoxi-drops, a
bubblegum-flavored liquid of which the normal dose is 0.2 ml/lb. But amoxicillin
capsules can also be used and mixed into a liquid at home. Amoxicillin tastes
okay to most rats and so is usually no problem to give in any form. An
occasional rat will hate the taste.
Amoxicillin is one of the only antibiotics that is perfectly safe to
give to pregnant and nursing mothers and babies of any age. (Another is cefadroxil, and cephalexin
can be given to nursing mothers as it does not enter the milk.)
Amoxicillin usually comes in a 250 mg capsule, which contains 25 1-lb.
doses. To make the dose 0.3 ml/lb,
mix one amoxicillin capsule with 7.5 ml of flavoring. (25 X 0.3 ml = 7.5
ml) The dose for a half-pound rat
is 0.15 ml. The dose for a 1¼-lb rat is 0.4 ml. To make the dose 0.1
ml/lb, mix one capsule with 2.5 ml flavoring.
Some vets won’t prescribe amoxicillin for rats because they learn in vet school that amoxicillin can kill hamsters or guinea pigs, so they sometimes generalize this to all rodents. Here are some references for vets to check if they are reluctant to prescribe amoxicillin:
Exotic Animal Formulary, Third Edition, James W. Carpenter, MS, DVM editor, Elsevier Saunders Publishing, page 377, Antimicrobial and antifungal agents used in rodents. Ampicillin for mice and rats: dosage 20-50 mg/kg PO, SC, IM q12h (Note: ampicillin and amoxicillin are essentially the same)
ViN (Veterinary Information Network, Inc.) Website:
Thomas Donnelly, BVSc on 02/05/2006 “Amoxicillin is safe to give
rats.”
Johanna Briscoe, VMD, on 07/08/2004 “I have used Clavamox liquid in a
rat and it worked beautifully on an abscess that I thought may have been from a
bite…. Clavamox dose same as
in other mammals—13.75 mg/kg PO BID.”
Elizabeth Mitchell on 06/01/2007 “I have used Clavamox a few times
in rats without problems, although I am always very careful to warn owners to
watch for diarrhea.”
doxycycline
Doxycycline is
related to tetracycline but is absorbed better and does not bind to minerals as
much. Doxy tends to work well
against Mycoplasma in rats, but is not good for much else. It is
bacteriostatic. This is the second
antibiotic I recommend trying for respiratory symptoms in rats after
amoxicillin. It often works well
together with enrofloxacin. It
should not be used in pregnant or nursing moms. It can increase the side effects of digoxin
, so enrofloxacin is better for rats on digoxin.
The usual dose is 2.5 mg/lb BID1 ,12 but this can be doubled if it
doesn’t seem to be working well.
Because it is used in rats mainly for Mycoplasma, it should be
given for a minimum of 6 weeks at a time, and is safe for very long term use.
The most common brand prescribed by vets is Vibramycin, a flavored
liquid, but capsules can also be mixed into a liquid at home. Most rats don’t mind the taste of
doxy, but some absolutely hate it and will fight against taking it. In this case, it is usually best to use
enrofloxacin instead.
Doxycycline comes in a 100 mg capsule, which can be mixed into a
liquid. A 100 mg capsule contains
40 1-lb doses. To make the dose 0.3
ml/lb, mix one capsule with 12 ml of flavoring. (40 X 0.3 = 12 ml) To make the dose 0.1 ml/lb, mix the
capsule with 5 ml of flavoring.
Baytril (generic name: enrofloxacin)
Enrofloxacin is a broad spectrum antibiotic in the fluoroquinolone
family. It is bacteriocidal. It is particularly good for Mycoplasma. It can also be good for urinary
infections, especially when used along with amoxicillin. It can safely be used very long term in
rats (ie. 2 years!) Other brand names
are usually similar to enrofloxacin, ie. Enrofloxin.
Enrofloxacin can be combined with doxycycline, penicillins,
cephalosporins or gentamicin. Do
not use it with chloremphenicol. It
can interfere with the metabolism of bronchdilators, so doxycycline is
better to use for rats on a bronchodilator.
The brand usually prescribed by vets is Baytril. The injectable form is
usually 2.25% (22.5 mg/ml). Vets will sometimes want to give Baytril by
injection, but it is highly caustic: DO NOT give Baytril by IM injection
and only SQ when absolutely necessary as SQ injections can cause
severe skin ulcers which take a very long time to heal. I know of two rats who bled to death
after scratching these ulcers!
Some vets grind Baytril tablets and mix them in a liquid
flavoring. These preparations
should probably be refrigerated. The injectable liquid, which can be given
orally, or 10% oral liquid should NOT be refrigerated because it will
crystalize.
The recommended dose of enrofloxacin for rats is 10 mg/lb4
BID for at least 6 weeks or long term.
A generic 10% oral liquid (100 mg/ml) is available inexpensively from
pigeon supply companies. The dose for the 10% liquid is 0.1 ml/lb BID.
Clear liquid Baytril, either injectable or oral, tastes pretty bad, but
most rats will take it from a syringe mixed with Karo syrup either half and
half or 2:1. You can also mix it in
2 teaspoons of an adult liquid supplement, such as Ensure, or soy infant
formula, in a baby food jar lid on a flat magnet so the lid won’t tip over. Don’t mix a lot of it up ahead of
time as that may affect its potency.
Other
Antibiotics
Although
amoxicillin, doxycycline, and enrofloxacin will take care of most infections in
rats, occasionally another antibiotic will be necessary, or can be tried if
others aren’t available.
Bacteriocidal
Antibiotics
gentamicin*—An aminoglycoside. Broad spectrum.
Good for serious systemic, respiratory, and urinary infections. Effective
against Mycoplasma. Best used with amoxicillin. Decreases cardiac
output. Can accumulate in the
kidney and inner ear, causing toxic damage; this isn’t common in rats but
encourage patient to drink plenty of fluids. The toxicity is increased by
furosemide. Not absorbed by the digestive
tract, so must be injected or nebulized. Do not use in pregnant rats. 1-2 mg/lb1 SQ BID for 7-14
days. Brands: Gentocin, Garison
metronidizole^—Used to treat anaerobic bacteria
which can cause serious infections in bone, a tooth socket, etc. Don’t
use in rats with neurological disorders.
Use with caution in rats with heart disease. Tastes really
horrible. 10-30 mg/lb 2-3
times/day.1 Brand:
Flagyl.
trimethoprim-sulfa^—Broad spectrum. Not effective
against Mycoplasma. Good for some skin, urinary, and secondary
respiratory infections, but amoxicillin seems to work better in most cases for
rats. It’s best feature is
that it penetrates all tissues well.
Can cause allergic reactions and renal obstruction. Patient must drink plenty of water. Long term use can decrease tear
production and cause vitamin K deficiency. Enhances activity of aspirin, NSAIDs
and furosemide. 15 mg/lb BID1
for 2-3 weeks. Brands: Tribrissen, Septra, Bactrim. Tastes terrible. Some rats will not take the liquid; use
tablets ground up in food instead.
Fluoroquinolones
Broad spectrum,
good for Mycoplasma.
ciprofloxacin—Not absorbed as well as
enrofloxacin. Use a dose of 15-20
mg/lb BID for at least 6 weeks.
difloxacin—Supposed to be better absorbed and
stay in the body longer than enrofloxacin, and doesn’t taste bad. One member had good luck at a dose
of 4.6 mg/lb BID. The dog dose says to use it for two to
three days beyond the cessation of clinical signs to a maximum of 30 days. Brand: Dicural.
Penicillin family
Broad
spectrum. Good for secondary
infections, but not Mycoplasma. Safe for pregnant/nursing mothers.
ampicillin—Good for urinary and secondary
respiratory infections, and preventing infection after injury or surgery. Use
similar to amoxicillin. Do not use
with atenolol. 20 mg/lb BID for at least 2-3 weeks. Taste okay.
amoxicillin
trihydrate/clavulanate^—Effective
for some bacteria that are resistant to amoxicillin. Good for skin infections and abscesses.
Some individuals are sensitive to the clavulanate ingredient. 10 mg/lb BID for 2-3 weeks. Brands: Clavamox,
Augmentin. Most rats like it.
penicillin—Use and precautions similar to
amoxicillin, but not as broad spectrum.
12-18 mg/lb or 20,000-30,000
IU/lb BID.1
Cephalosporins
Similar to the
penicillins, but broader spectrum.
Not good for Mycoplasma. Good choice for serious infections that
don’t respond well enough to amoxicillin. Give for at least 2-3 weeks.
cefadroxil^—Good for secondary respiratory
infections, urinary, skin and soft tissue infections and prevention after
surgery. 10 mg/lb BID. Brand:
Cefa-drops. Tastes good.
cephalexin—Good for skin, urinary, bone
infections, septicemia, respiratory infections. Do not use with gentamicin. Can be used with chloremphenical. Brand:
Keflex. Dose for children: 12-25 mg/lb 4 times a day.
cefuroxime—Strongest of the 3 cephalsporins
listed. Good for respiratory,
urinary, skin, bone infections, septicemia and meningitis. Brand: Ceftin.
Childrens dose: 10-25 mg/lb BID
Bacteriostatic
Antibiotics
chloramphenicol^—Broad spectrum, penetrates tissues
that some other antibiotics can’t, like the central nervous system and
eye, but not good for urinary infections.
Effective against Mycoplasma. Can be bacteriocidal at high doses. Do
not use in babies, or along with aspirin, NSAIDS, macrolides, penicillins, or
aminoglycosides. Long term use can
depress the bone marrow. Decreases
cardiac output and prolongs the effects of barbiturates. An oral liquid can be specially mixed at
pharmacies. Tablets are
generallynot available because if humans inhale the powder it can cause
aplastic anemia. Chloremphenicol
palmitate: 25-90 mg/lb 2-4 times/day orally, tastes bad so easier to inject;
chloremphenicol sodium succinate: 15-25 mg/lb BID SQ for 7-14 days.4
clindamycin^—Used to treat anaerobic bacterial
infections such as serious infections of the bone, tooth socket, deep wounds,
etc. Effective against Mycoplasma. Do not use with macrolides. Use with caution in rats with
allergies. Tastes horrible; easier
to give by SQ injection (injectable not readily available, check at human
hospitals). Brand: Anti-robe. Dose: 5-10 mg/lb BID1 for 2-4 weeks.
Macrolides
Variously
effective against Mycoplasma.
erythromycin^—Effective against Strep, Staph,
Corynebacteria. Good for
abscesses and prostate and some respiratory infections. Do not use with clarithromycin,
ketoconazole, or enalapril. 10 mg/lb.
Brand: Ornacyn (pet store) ½-1 tablet in ¼ cup drinking
water mixed fresh daily, or ¼ to 1/3 tablet in food TID.8 Tastes okay. Don’t give in fruit juice. Fish
capsules available but taste really bitter.
azithromycin^—Stronger than erythromycin. Some people report excellent success
against some strains of Mycoplasma but my experience is that symptoms
quickly come back once treatment stops.
It could be that it needs to be given for much longer. Brand: Zithromax. The human dose is 4
mg/lb BID for 2 weeks, then SID for 2 weeks4 but one member suggests 5-15 mg/lb BID
for at least 3 weeks. Best given on
an empty stomach, at least 2 hours after eating. Do not refrigerate.
clarithromycin—Stronger than erythromycin. Good for respiratory and skin
infections. Do not use with
cisapride or digoxin. Use with
caution in rats with heart or kidney disease. The best dose for rats unknown. Brand: Biaxin. Human dose: 1.5-5 mg/lb
BID for probably 3-6 weeks. Tastes
horrible.
tylosin*—Effective only against Mycoplasma,
so not good for secondary infections.
4.5 mg/lb BID4 for at least 6 weeks. Tastes horrible!!! Brand: Tylan Soluble (feed stores,
catalogs) 1/8-¼ teaspoon in 1 cup drinking water mixed fresh every 3
days, or 1/64 teaspoon/lb in food BID.8 (To get 1/64 teaspoon, dump 1/8 teaspoon
on a small plate and divide into 8 equal piles. Each pile is a dose.) Also Tylan injectable.
Tetracyclines
Broad spectrum,
fairly effective against Mycoplasma.
tetracycline,
oxytetracycline*—Broad
spectrum, effective against Pasteurella abscesses. Good for respiratory infections,
prevention of infection after injury or surgery. Don’t use in pregnant or nursing
animals. Do not use with dairy products because calcium and magnesium can bind
to tetracycline and deactivate it. Do not use with digoxin. Patient must drink plenty of water. Dose: 25 mg/lb TID4 for at
least 6 weeks. Brands: Panmycin Aquadrops, fish capsules. Terramycin soluble powder (feed store)
1/8 teaspoon in food TID. 8
Tastes okay.
chlortetracycline—May be more effective than
tetracycline or oxytetracycline, but tastes worse. Dose half that of Terramycin.8
Brand: Aureomycin Soluble Powder
(feed store).
Sources for
Antibiotics
Some antibiotics
can be purchased over the counter for different animals: amoxicillin and
ampicillin for aquarium fish;
doxycycline, enrofloxacin and trimethaprim sulfa for birds; gentamicin,
tetracycline and tylosin for livestock/poultry. Prescription drugs can be purchased
either from your vet, a human pharmacy (often cheaper), or a mail order
catalog.
When ordering an antibiotic by mail order, be sure to specify if you
want capsules or liquid, or you might get loose powder or tablets
instead.
Here are some sources:
Jedds Pigeon Supplies *my preferred source, 800-659-5928 (amoxi and doxy capsules, and 10% liquid
enrofloxacin can be ordered by phone, ask for Greg)
Doctors Foster & Smith, 800-826-7206 (100 amoxicillin capsules for fish.)
Global Pigeon Supplies, 800-562-2295, www.globalpigeon.com (10% liquid
enrofloxacin, doxy)
Siegel Pigeons, 800-437-4436, www.siegelpigeons.com
Jeffers, 800-JEFFERS, www.jefferspet.com (doxy)
Omaha Vaccine Company, 800-367-4444 (amoxi)
Cal Vet Supply, www.CalVet Supply.com (amoxi, doxy)
A Note About Doses
I have not included liquid doses for all medications because the dose will vary
with the concentration of the liquid. Here is how you convert a dose in mg to a
dose in ml. Find the concentration of the medication, which will be in mg/ml.
Divide this number by the dose in mg. Divide the results into 1. For example,
if the concentration is 50 mg/ml, and the dose you want is 10 mg, you need to
divide 50 by 10. This gives you the number of doses in one ml, in this case, 5.
Dividing 5 into 1 gives you the dose in ml, in this case 0.2 ml. (One ml is
exactly the same as one cc.)
To determine how many doses in a tablet or capsule, divide the strength of the pill by the required dose. For example, if the pill contains 50 mg and the dose is 2 mg, you divide 50 by 2, and you find that the pill contains 25 doses. If you need help figuring out doses, just give me a call.
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