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Injectable Doxycycline = Vibravenous/Vibravenos
A drug option for aggressive respiratory infections
(References numbered at bottom of page)

Over the past year or so, a certain type of medication has received some slight but much deserved attention as a tool in the fight against respiratory infections in rats. Practically all pet rats have a bacteria (Mycoplasma pulmonis) in their lungs, and this bacteria is usually responsible for the respiratory problems that are so common in pet rats because myco gradually damages the lungs - making rats more prone to secondary respiratory infections. Vibravenous (or Vibravenos) tetracycline is an injectable, slow-release form of doxycycline (1). Doxycycline is not a new drug for rats - it is commonly prescribed as a suspensions that rats are given orally. However, this injectable doxycycline is somewhat different. It is compounded and given either intramuscularly or subcutaneously. I have firsthand experience of how effective this special doxycycline is. It saved one of my rats who was very ill in May 2002. After reading about Vibravenous on the ratlist a while back, I was under the impression that it could only be obtained from one vet in the Netherlands. However, after my own experience and doing some research I believe that some vets in Canada, the US, Europe and Australia have access to this drug.

Vibravenous is usually given intramuscularly which means a shot in the hind leg(s). The hind legs are very sore for about 24 hours afterwards. Injections can stressful for animals. The severity of the infection should be taken into account before using Vibravenous. A vet will probably recommend that a rat showing mild symptoms begin with an oral dose of medication. Vibravenous is probably best kept in mind as an option for rats which do not respond to oral medication, or for rats that are so ill that they will not eat or drink.

My experience

In May of 2002 my rat Rimsky suddenly became very ill with a respiratory infection. Previous to this, he had been on azithromicin for a couple of weeks to try and clear up some mild symptoms but then he suddenly went downhill. He was extremely lethargic, breathing heavily and refused to eat. He would only take a little water from a syringe. A trip to the emergency vet wasn't very helpful (no proper antibiotics) but Rimsky did get some sub-cu fluids and oxygen. Rimsky had to wait until the morning to see a regular vet. In the morning, Rimksy looked near death, laying on his side heaving. We went in to see an exotics vet and they had some injectable doxy. Rimsky received an intramuscular injection of the doxy in two spots (one in each hind leg). Once I brought him home, I wondered if I had made the right decision because he looked to be in such awful shape. However, 12 hours later I could tell he was improving and 24 hours later he was back to his old self, jumping on the cage door and ready to come out and explore. I was amazed. This is known as the "booster effect", a characteristic of injectable doxy. Noticeable improvement is observed in 12 hours or less. Oral doxy does not have this boostering effect, but rather causes a gradual improvement. (1a). This booster effect is very important for rats that are very ill and need immediate relief. Rimsky received another injection 7 days after the first. It is very important to give the second dose because the improvement caused by the booster effect is temporary. Seven days after the second injection Rimsky was put on oral doxycyline. For the most part he stayed on the oral doxy for seven months before he died suddenly of a stroke/heart attack. Extended use of antibioitcs is never a good plan, but the three times I took Rimksy off the oral doxy he had a flare up again within days where he would sound congested again.

Others' Experiences

Direct quote from Jane Adamo, ratlist message 51601 "I, and a number of other RatListers have seen incredible, wonderful, fast, effective results in treating myco symptoms with this medication. ... YOU CAN EXPECT DRAMATIC RESULTS IN TREATING THE SYMPTOMS OF MYCOPLASMOSIS IN RATS WITH THIS MEDICATION." (2)

Dosage

I asked about the dosage of the medication that Rimsky had received and all the vet told me was that the concentration of the solution was 100mg/5mL. I snuck a peek at one of Rimsky's patient sheets and it said that he had received 1 cc (1 mL). I intend to get more detailed information and verify this information the next time I go to the vet. From this information, I tentatively believe that Rimsky received 20 mg. He is roughly 500g (0.5 kg or 1 lb) in weight, so he got a dose of 40mg/kg (or 20mg/lb). This seems a bit low compared to some other things I have read.

I found this on the ratlist:

Written by Cyndi Brown, DVM (Resident, Exotic Animal Service, The Animal Medical Center (3):

"The current dose we use here at the Animal Medical Center is extrapolated from the published per Os (oral) dose for rats/mice in the Exotic Animal Formulary, 2nd edition, Carpenter, Mashima, Rupiper, Saunders Publishing. The recommended oral dose is 5 mg/kg twice daily. The Vv [Vibramycin/Vibravenous] is a slow release formulation which we dose at intervals of every seven days. {5mg/kg x 2 times per day = 10mg/kg per dayx 7 days = 70mg/kg} The dose we use is 70mg/kg every seven days. The concentration of the Vv we receive here is 20mg/ml. The volume of drug ends up being quite large for such small critters and for that reason we administer it subcutaneously. As you both know from personal experience injection site reactions do occur (a very rough estimate would be 10-15% -although a formal tabulation has not been performed - this is just my clinical experience.

An example calculation for you.

"400gram Rat = 0.400 kg 0.400kg x 70mg/kg = 28 mg
28 mg divided by 20 mg/ml = 1.4 mls

The volume to be administered to a 400 gram Rat would be 1.4 mls (or cc's) of a
20mg/ml Vv solution

Remember1000 g = 1 kg and one milliliter (ml) equals one cubic centimeter (cc)" (3)

Subcu (as opposed to intramuscular) injection may require that the medicine be mixed with a buffer within 10 seconds prior to injection. It also may still burn the skin. (4)

Okay, so where do I get this?

The Links Road Animal Clinic in Toronto (near the intersection of Yonge St. and the 401) has this form of long-lasting doxycycline (that's where Rimsky and I went). It is an exotic animal clinic so I'm guessing that they have it on hand because they treat a lot of birds. Their address and contact info are in the recommended vets section of the Pet Rats Canada site. According to one of the vets there, the Links Road Animal Clinic is one of the few places where Vibravenous is available in North America.

The following paragraph is a direct quote from a document on the American Veterinary Medical Association that I found with regards to birds. Vibravenous has been established as an effective treatments for avian chlamydiosis.

"Intramuscular (IM) injection into the pectoral muscle is often the easiest method of treatment, but not all injectable-doxycycline formulations are suitable for IM injection. All available formulations can cause irritation at the injection site. The VibrovenosTM formulation (Pfizer Laboratories, London, Ontario, Canada) is available in Canada and Europe and is effective if administered at doses of 75-100 mg/kg body weight IM every 5-7 days for the first 4 weeks and subsequently every 5 days for the duration of treatment. Anecdotal reports indicate that pharmacist-compounded, injectable-doxycycline products have been used successfully in the United States. However, data are insufficient to determine precise dosage schedules. The injectable-hyclate formulation labeled for intravenous use in humans in the United States is not suitable for IM use in birds because severe tissue reactions will occur at the site of injection." (5)

The following quote is from the August 2001 Newsletter of Antech Diagnostics, a nationwide network of integrated veterinary diagnostic laboratories - published online 3/25/2002 (again, it's related to birds)

"While chlamydiosis can be diagnostically perplexing, infections respond readily to treatment with doxycycline. Preparations designed for oral, intravenous and intramuscular (Vibravenous®, Pfizer) administration are available in the United States. This eliminates the need for compounding of doxycycline. A single injection of doxycycline will maintain blood levels for 5 –7 days. Therapy for severely ill birds with suspected chlamydiosis should be initiated with an injectable, rather than oral, form of doxycycline." (6)

Vets at the Animal Medical Center in Manhattan, New York City apparently have experience with administering Vibravenous to rats. (7)

If none of the vets in your area have access to this medication, you can attempt to order it but I don't know how successful this would be. Here is some information you might need (from the ratlist). There appears to be some conflicting information about the time-frame within which the medication is effective once it has been exposed to air (7,8a,10):

"my vet did tell me that the stuff begins to lose effectiveness within 24 hours after the glass module is opened. Her information comes from Dr. Natalie Antinoff, another vet in Houston, who interned at the clinic in New York that Jane Adamo uses. ... Also, according to my vet, the stuff cannot be put in another container to be saved--once the bottle is opened, the countdown to ineffectiveness begins, and that's pretty much it. Because of this, she couldn't just sell me a portion of it for the few rats who were sniffly--she had to sell me the entire module, which
was over $100. She recommended I just treat all my rats with it--one module easily covered 10 rats. The following week, I had to buy another module for all of them. Expensive, yes, but if it prevents even two myco outbreaks, I've saved money." (8a)

"When V Tet. is "out of the bottle" for awhile, it turns brown, but that does not immediately affect it's effectiveness. Dr. Canny didn't know if the medication "gets old" (loses it's effectiveness as a function of time). Keep it in the fridge." (7)

"One thing people should know is that you can't use the stuff right from the manufacturer, because it comes in a glass 'bubble'. It needs to be decanted by a vet (or else you will make a huge mess and waste the stuff:) We have *never* used 5cc, more like .15cc, but our stuff may be more concentrated (looks like a thick maple syrup that must be kept in the fridge)." (7)

"I talked to my compounding pharmacist about the vibravenous tetracycline to see if he could get it. He can, but the problem comes in processing it. The drug is available and not even very costly, but it takes a very expensive machine to process it for use. He can't afford the machine for just my rats. RATS!" (7)

In Australia:

".. long-acting injectible doxycycline. Odd thing is though, it's not approved legally yet [in Australia] so vets in Aus can't actually buy it. But pet owners an obtain it through an online veterinary drug supplies store (www.vetafarm.com.au)"
http://www.vetafarm.com.au/show_product.asp?category_id=-1&item_number=0100E (8)

"PSITTAVET INJECTABLE 10mL Cost with shipping: $37.83 (after currency translation) + a phone call to Australia (but hey, it's worth it to hear the accent!)" (9)

"She [my vet] said it has an expiry date of several years" (10)

From the Netherlands

Contact info for Dr. Gerry Dorrestein, D.V.M., Ph.D., in the Netherlands is available from a document on the AVMA website (5). His address is listed at http://www.aav.org (Area Code 31, City=Utrecht).

References:

1. The Layman's Medication Guideline for Use in Rats. http://www.kuddlykorner4u.com/Doxycycline.html

1a. Ratlist message 89029 June 25, 2002. http://groups.yahoo.com/group/ratlist/message/89029

2. Ratlist message 88794 May 9, 2001. http://groups.yahoo.com/group/ratlist/message/51601

3. Ratlist message 48741. Apr 18, 2001. http://groups.yahoo.com/group/ratlist/message/48741

4. Ratlist message 82720 Apr 4, 2002. http://groups.yahoo.com/group/ratlist/message/82720

5. From the American Veterinary Medical Association website: Compendium of Measures To Control Chlamydophila psittaci (formerly Chlamydia psittaci) Infection Among Humans (Psittacosis) and Pet Birds, 2002. Appendix B. http://www.avma.org/pubhlth/psittappendb.asp - (lists some sources for medication).

6. From the website of Antech Diagnostics: August 2001 Newsletter. http://www.antechdiagnostics.com/clients/antechNews/2001/8-01.htm

7. Ratlist message 77544. Feb 1, 2002. http://groups.yahoo.com/group/ratlist/message/77544

8. Ratlist message 82701 Apr 4, 2002. http://groups.yahoo.com/group/ratlist/message/82701

9. Ratlist message 85019 May 2, 2002. http://groups.yahoo.com/group/ratlist/message/85019

10. Ratlist message 82721 Apr 4, 2002. http://groups.yahoo.com/group/ratlist/message/82721

8a. Ratlist message 88982 June 24, 2002. http://groups.yahoo.com/group/ratlist/message/88982

Disclaimer:
This information is by no means intended to replace the advice of a veterinarian. I strongly suggest that anyone who has a rat with a respiratory infection (or any other health concern) discuss all treatment options with their vet. Under no circumstances can anything found in the forum, or anywhere else on the Pet Rats Canada site, be construed as professional veterinary advice or instruction. All vet care discussion at Pet Rats Canada is intended for the purpose of assisting you in discussing options with your local vet. Any other use is done at your risk and is solely your responsibility.