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Pet Rats/Medication mixing and calculations for rat with eye issue


Hi Debbie,

I have read all your answers here and enjoy your website and all the valuable information, but I have some additional questions.

I have two adorable boy rats that are about 1 year old, Murphy and Fynn. They were rescued from a shelter and as soon after I got them home I noticed the myco raspy breathing. I took them to the vet and $95 and a month later they were both recovered. Then in a month Fynn started to have redness around the eye and porphyrin discharge with swelling. So back to the vet and she prescribed another round of baytril and doxycycline. However the eye is not improving much after 3 weeks - swelling has gone down, but red rim and discharge has not, so I am starting him on Amoxicillin. He got a double dose tonight of 20mg.

Also, I have ordered Enrofloxacin from Jedd's because the vets version is so expensive. I have Enrotex 2.5g/100g of sugar (maltodextrin, I think) - a powder. I need help with these calculations, please. I don't want to risk ODing Fynn or giving ineffective treatment. This would be for now or future use, depending on if I continue the Baytril at all. I like to give small amounts in solution, no more than 0.2 to 0.4 ml/dose mixed with half a tsp of wet cat food, as this is always eaten on a spoon and licked clean :)

The Enrotex instructions say 1 tsp is 5 grams. This is for birds and these instructions aren't clear so I called Jedd's for clarification on if that 5 grams is total powdered mix or 5 grams of active enrofloxacin. The 5 grams refers to TOTAL weight, which would be in actuality be 125mg of active ingredient, enrofloxacin. I have a scale that I can weigh out with accuracy to 0.1 oz. My Rat and Mouse Gazette Medication Guide states that Baytril is administered at 5mg/lb, but again this seems to be referring to a 2.27% formula so I would think this does not mean 5mg of 100% active enrofloxacin.

So.. Question 1) How do I measure out this Enrotex powder in a solution that can give a proper dose at 0.2ml to 0.4 ml


2) Do I stop the Enro and Doxy and switch to just Amoxicillin? I am reluctant to stop the other treatment early, even though  ineffective because I don't want to create immune organisms that he could harbor and then as a result cause problems with future myco treatment that may be needed, given his history.

3) Is it safe to give all three antibiotics at once? (I've lost rats to myco and eye infections before and want to know so I can take care of emergencies)

Thank you so much in advance.

Hi Katy,
In the future you can just email me at if you want.

You can give all 3 antibiotics at the same time. However, if the doxy or Baytril aren't helping, you might not want to keep giving them.

Since 1 tsp of the Enrotex powder contains 125 mg of actual Baytril, and the dose I recommend is 10 mg/lb (this works much better than what RMCA says), then 1 tsp contains 12.5 doses and 1/8 tsp contains 1.5 doses. So you can just mix the powder right in the cat food. If in doubt, give a little extra. Better to give extra than risk not getting enough.

See more info below on ordering Baytril and other antibiotics.

You can buy 100 ml of 10% oral generic Baytril (enrofloxacin is the generic name but it can be called enroxil or enrofloxacine) from pigeon supply companies for birds. The dose for a 1-lb rat is 0.1 ml, which means that 100 ml is 1000 rat doses!  Very economical.   You need to give it twice a day.  Do not refrigerate the Baytril!

I’ve had the best luck giving Baytril in 4-6 ml of a product such as strawberry Ensure or Boost in a baby food jar lid, or in 1/8 teaspoon of the soy baby formula powder, making a paste.  It helps if you put the baby food jar lid on a small magnet to help keep your rat from tipping it over.  

You can order it from

You also want to buy a few 1 cc syringes for dosing (take off the needle and throw it away), and you can buy syringes at most pharmacies.

You can order doxycycline capsules here:
If you would prefer a liquid they also have Doxysyrup or Doxyvet Liquid. Most people will want to order Doxysyrup, which is 10 mg/ml. The normal dose is 0.25 ml/lb twice a day. If necessary you can give twice this.

If you own a lot of rats, the most economical choice is Doxyvet Liquid, which is 50 mg/ml. The normal dose is 0.05 ml/lb twice a day. If necessary you can give twice this. I have heard from several rat owners that this liquid is not as palatable as the Doxysyrup, but it can be diluted with yummier liquid or mixed with food. If you mix 1 ml of the Doxyvet with 5 ml of flavoring, and then the dose is 0.3 ml/lb twice a day. Depending on the flavoring you use, the mixture should probably be refrigerated.

You can also order 100 mg capsules of doxycycline at a good price on eBay at  This company is in Singapore, so expect shipping to take 3 weeks.

For 100 mg capsules or packets of doxycycline, mix one capsule or packet with 12 ml of flavoring (slightly diluted strawberry syrup works good) and then the dose is 0.3 ml/lb twice a day. Store in the refrigerator and stir before taking out a dose.

You will find more info about treating respiratory infections on my website at on the Rat Info page.  I also highly recommend you order my Rat Health Care booklet.  It is only $7 plus $2 shipping (CA residents add 58 cents tax.)  The address is Rat Fan Club, 857 Lindo Lane, Chico CA 95973.

Amoxicillin is the best treatment for secondary infections, of which lethargy is a leading symptom.  Amoxicillin capsules are good to have on hand for secondary infections, which can be very severe very quickly, and can need immediate treatment.  

All vets will have amoxicillin, and you can also get amoxicillin over the counter as aquarium fish capsules from some feed stores and fish stores.  However, a lot of stores are choosing to no longer carry them.  If you can’t find amoxicillin, you can use ampicillin which is basically the same thing, it just isn’t absorbed as well, so just double the dose to 20 mg/lb twice a day.

Some vets won’t prescribe amoxicillin for rats because they learn in vet school that you can't give amoxicillin to hamsters or guinea pigs (it will kill them) so they sometimes generalize this to all rodents.  But amoxicillin is fine for rats, I use it all the time.  Occasionally you will have an individual who will be allergic or sensitive to it, but this is not very common.  The most common side effect is diarrhea.

You can get amoxicillin mail order from If your rat is already sick, be sure to ask for overnight delivery!  

You need to know about how much your rat weighs.  The dose is 10 mg/lb twice a day but you can safely go as high as 50 mg/lb.  In most cases (check the package) each amoxicillin capsule contains 250 mg, which is 25  1-lb doses.  

You can buy a 1 ml syringe at most pharmacies. A 12 cc or 3 cc syringe is also helpful for measuring the flavoring liquid. You can mix the amoxicillin in a liquid such as slightly diluted Hersey’s strawberry syrup, Ensure, apple juice, milk, etc. A short pill bottle is about the right size to mix it in.  . Amoxicillin does not dissolve but forms a suspension. The powder will sink to the bottom, so before taking out a dose, you need to stir the mixture with the syringe extremely well, being sure to scrape up all the powder off the bottom so it is in suspension.

Amoxicillin doesn’t taste too bad to most rats, so I suggest making the liquid dose 0.3 ml (30 units on an insulin syringe) per lb.  Multiply the volume of the dose by the number of doses in the capsule:  0.3 ml times 25 doses equals 7.5 ml.  So you mix a capsule in 7.5 ml of liquid.   Keep in the refrigerator.  If your rat won’t take this voluntarily, you can make the dose 0.1 ml which is too small for them to spit out.  0.1 ml X 25 = 2.5 ml so you mix one capsule with 2.5 ml of tasty liquid.

Give the dose twice a day.  If it's going to work the symptoms should improve within 2-3 days.  If it does work you need to continue the treatment for at least 2-3 weeks.  If it doesn’t work then you need to try a different treatment.  

If this treatment is going to help you should see improvement within 2-3 days.  If the symptoms are all gone within 3 days you should continue the treatment for 3 weeks.  If it takes longer for all the symptoms to go away, give it for 4-8 weeks and maybe longer.  The longer it takes for all the symptoms to go away, the longer you should continue the treatment.  If the symptoms stop improving, or if the amoxicillin doesn't help at all, you will need to try something else.

Concerning amoxicillin and veterininarians:  Many vets don’t want to use amoxicillin on rats.  This is probably because in vet school they learn that amoxicillin can’t be used in guinea pigs, rabbits or hamsters (because it kills the good bacteria in their intestines), and they probably generalize this to rats and mice.  However, rats and mice usually tolerate amoxicillin quite well.  In my experience only a very small percentage of them will get diarrhea from it, and this is not life-threatening; it will usually clear up with a probiotic, or the amoxicillin can be stopped.

Here are some references for using amoxicillin in rats for your vet 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 have essentially the same adverse reactions and effectiveness, so they can be used interchangeably)

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.”

Blackwell’s Five-Minute Veterinary Consult: Small Mammals, Second Edition, Barbara L. Oblesbee. 2011 John Wiley & Sons, Inc. page 588, “amoxicillin/clavulanic acid (12.5-15 mg/kg PO q12h) may also be used.”

(Note: Clavamox is the brand name for a mixture of amoxicillin and clavulanic acid.)

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Debbie Ducommun


I can answer any questions about pet rats, but you will probably be able find answers to simple questions more quickly on my website at If you have a life-threatening emergency you can try calling me at 530-899-0605. I am not usually on the computer on the weekend.


I have been "The Rat Lady" since 1985 and am recognized as one of the world's experts on pet rats. I have 3 published books and already answer lots of questions about rats daily.

President of Rat Assistance & Teaching Society

I am a monthly columnist for Pet Business magazine, and my writing has appeared in other magazines. I have 3 published books.

BA in Animal Behavior

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