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Medical Misinformation on the Internet and how it can Harm your Tortoise - Chris Tabaka DVM

Copyright © 2003 World Chelonian Trust. All rights reserved

While the internet is an incredible invention allowing vastly improved communications as well as conveying tremendous amounts of information rapidly, one of my primary concerns with it as a clinician is the amount of medical misinformation that is being and has been published on the web.  While most of this information is relatively harmless, it is the medical (as well as husbandry) misinformation that concerns me the most.  Too many turtles and tortoises have been affected by this misinformation due to well meaning owners who believe what has been posted.

Due to several bad experiences, I decided long ago not to send out nor publish drug dosage information.  The dosages were either being altered or the drugs were being utilized in inappropriate situations.  However, this does not stop many with no medical training nor continuing education to publish non-peer reviewed nor referenced medical information as fact across the internet.  Unfortunately this type of behavior is not only irresponsible but can also cause varying degrees of harm.  When you take into account that developed dosages are based on healthy animals of at best one or two species, the potential for error and the need for professional expertise increases exponentially.  I’m going to cover two drugs in this article that are widely and often carelessly utilized which are capable of causing great harm. 

The first of these is an anthelmintic (a drug that “expels or destroys parasitic worms especially of the intestine”) by the name of Panacur.   Panacur is actually a tradename for a drug called fenbendazole which belongs in the benzimidazole drug family.  This drug is perhaps the most commonly used treatment in chelonian medicine.  Because of this wide usage, I feel it is often forgotten that this is still in fact a drug which is capable of doing great good as well as great harm.

Dosaging information on the internet is invariably specific as to what dosages should be utilized in your chelonian to “cure” it.  However, this is quite simply not the way medicine works.  Medicine is as much art as it is science and years of clinical training as well as clinical experience go into a veterinarian’s dosaging recommendations.  Factors that need to be taken into account include the species that is being treated, the physical condition of the animal that is being treated, the hydration status of the patient, the age of the animal, the body size of the animal (NOT just the weight), the parasite load of the animal through diagnostic testing, the published dosages for the drug, and the combined clinical experiences of the veterinarian prescribing the medication. 

So, for example, if you had a brand new Asian turtle from the animal markets that came in severely dehydrated, malnourished, and with a heavy parasite load, would you instantly treat it at the “standard internet” Panacur dosage?  If so, you are not only risking drug toxicity but also the potential for GI obstruction from the sudden death of a massive parasite load.  Yet while this information is basic knowledge for a clinician prescribing the medication, the impersonal, and often unqualified, internet makes no such distinctions.

Another thing to note with Panacur is that its effectiveness is continuing to fade progressively and rapidly as resistance develops.  I am seeing more and more cases of parasite loads that barely flinch after a prescribed regimen of fenbendazole and thus I am utilizing this drug less and less due to this resistance. 

Next, Panacur is not effective against all types of parasites.  Fecal exams are ESSENTIAL for proper diagnosis as well as treatment.  Two quick examples are parasitic protozoal burdens such as Entamoeba as well as a common parasite in aquatic chelonia, tapeworms.  Neither of these are affected by standard Panacur dosages. 

Panacur also comes in many different forms and strengths.  In the United States for example, it comes in a powder form, a liquid form, and a paste.  Each of these forms varies in terms of its concentration and strength.  Precise calculations are needed to dose animals properly.  Improper dosaging can literally lead to death 2.   

Next, with all drugs there is a shelf life during which the manufacturer guarantees the drug will work as expected.  Once beyond that shelf life, the drug’s efficacy can decrease rapidly depending on the drug as well as the form it is in.  As an example, note in the picture above, this packet of panacur granules actually expired over two years ago! 

Lastly, while Panacur has always been considered a safe drug, a number of recent publications note the toxic side effects of this drug.  These side effects include everything from bone marrow toxicity to intestinal cell pathology to death in various taxa 1,5,6,7,8

A second drug that is widely utilized in chelonian medicine is Baytril.  Again, this is a tradename for a drug which in this case is enrofloxacinEnrofloxacin is a member of the antibacterial group, the fluoroquinolones.

Again, dosages for this drug are widely circulated on the internet.  Unfortunately, the utilization of drugs such as this is often inappropriate and even harmful.  Pathogenic organisms such as hexamita, viral organisms, fungal organisms, parasites, and protozoal organisms are all unaffected (or in some cases even encouraged by the destruction of their “competition”) by the usage of antibiotics yet are often the cause of the underlying problem in the animal.  Baytril can also have severe side effects.

For example, long term usage of antibiotics can destroy the normal gastrointestinal flora of chelonia.  This in turn can lead to the overgrowth of some rather nasty resistant bacterial organisms as well as fungal organisms.  Obtaining a culture and sensitivity is necessary to pinpoint exactly what organism is causing the problem as well as determining the most effective treatment option.  Bacterial resistance to numerous antibiotics is becoming the norm rather than the exception to the rule.  Having your vet run an inexpensive culture and sensitivity not only saves time but also improves the odds of proper and effective treatment.

A second side effect which I have noted personally in Geomyda spengleri, Geochelone denticulata, and Heosemys spinosa and which has been reported anecdotally in several other species is that baytril can cause a severe “allergic type” reaction in a number of animals.  This reaction consists of violent vomiting, diarrhea, and an almost comatose state with all four limbs and the head fully extended within a few minutes of the injection.  The comatose state can last varying periods of time stretching into a few days. 

Batyril was initially developed in dogs and the following information is from the label.  “Enrofloxacin may lower the seizure threshhold (meaning that it can facilitate seizures). This is not a problem for normal animals but fluoroquinolones are best not used in animals with known seizure disorders.”  Also note: “At approximately ten times the recommended dose vomiting and diarrhea may be seen with this medication. At normal doses, this should not be seen.  Dogs with Pseudomonas ear infections require very high doses of enrofloxacin and nausea may indeed become a problem.” 

Next, baytril is an EXTREMELY painful drug if given in the “wrong” place.  Intramuscular injections into the musculature of the front legs is an outdated treatment modality and leads to the classic ‘Baytril pain dance” which is easily avoided with appropriate administration of the drug.

Baytril has also been found to cause damage to the joint cartilage in immature (less than 8 month old) dogs.  I have seen this in immature birds as well and have no reason to believe it doesn’t cause similar problems in developing chelonians.  Permanent damage to the retinas in cats and subsequent blindness is another side effect which wasn’t discovered until the past few years. 

Lastly, most people are unaware that Baytril is actually designed to be given intramuscularly for the initial treatment and then orally for subsequent treatments.  It is not designed to be given repeatedly into the muscle yet this is the primary approach utilized in most instances as well as that “prescribed” by internet “experts”. 

To summarize, I would strongly encourage everyone to make full use of their veterinarian.  We are not only trained medical professionals but we have years of experience, continuing education, and diagnostic skills/equipment that can be brought to bear on your animal’s medical problems.  Relying on “cookbook drug recipes” on the internet is not only dangerous but also irresponsible.  The animals in our care deserve the best we can provide.

Reference list

1.Weber MA, Terrell SP, Neiffer DL, Miller MA, Mangold BJ Bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole administration in five painted storks. J Am Vet Med Assoc 2002 Aug 1;221(3):417-9, 369



Five painted storks were treated with fenbendazole for 5 days for internal parasitism. Four birds died following treatment. Profound heteropenia was a consistent finding in all samples evaluated; additionally, the 1 surviving bird had progressive anemia. Consistent necropsy findings in the 4 birds that died were small intestinal crypt cell necrosis and severe bone marrow depletion and necrosis. Fenbendazole has been associated with bone marrow hypoplasia and enteric damage in mammals and other species of birds. The dosages of fenbendazole used in birds are often substantially higher than those recommended for mammals, which may contribute to bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole administration in birds.

2. Alvarado, T., M. Garner, K.Gamble, G. Levens, J. Raymond, and R. Nordhausen. 2001. Fenbendazole overdose in four Fea's vipers (Azemiops feae). Proc. Annu. Conf. Am. Assoc. Zoo Vet. Pp. 28-29.

3. Barron, S., B.J. Baseheart, T.M. Segar, T. Deveraus, and J.A. Willford. 2000. The behavioral and teratogenic potential of fenbendazole: a medication for pinworm infestation. Neurotoxicol. Teratol. 22:871-877.

4. Dalvi, RR. 1989. Comparative studies on the effect of fenbendazole on the liver and liver microsomal enzymes in goats, quail, and rats. Vet. Res. Commun. 13:135-139.

5. Deiana, L., A.M. Congiy, C. Carru, G.M. Pes, and G. Arru. 1990. Embryotoxicity of fenbendazole in Paracentraotus lividus, Bull. Soc. Ital. Biol. Sper. 66:1137-1144.

6. Hayes, R.H., F.W. Oehme, and H. Leipold. 1983. Toxicity investigation of fenbendazole, an anthelmintic of swine. Am. J. Vet. Res. 44:1108-1111.

7. Howard, L.L., R. Papendick, I.H. Stalis, J.L. Allen, M. Sutherland-Smith, J.R. Zuba, D. Ward, and B.A. Rideout. 1999. Benzimidazole toxicity in birds.  Proc. Annu. Conf. Am. Assoc. Zoo Vet. Pp.36.

8. Papendick, R.I. Stalis, C.Harvey, B. Rideout, J. Zuba, J. Allen, and M. Sutherland-Smith. 1998. Suspected fenbendazole toxicity in birds. Proc. Annu. Conf. Am. Assoc. Zoo Vet. and Am. Assoc. Wildl. Vet. Pp 144-146.

9. Stalis, I.H., B.A. Rideout, J.L.Allen, and M. Sutherland-Smith. 1995. Possible albendazole toxicity in birds. Proc. Annu. Conf. Am. Assoc. Zoo Vet, Wo;d;/ Dos/ Asspc/. and Am. Assoc. Wildl. Vet. Pp. 216-217.

10. Stokol, T., J.F. Randolph, S. Nachbar, C. Rodi, and S.C. Barr. 1997. Development of bone marrow toxicosis after albendazole administration in a dog and a cat. J. Am. Vet. Med. Assoc. 210: 1753-1756.

Internet reference list:

Mar Vista Animal Medical Center - Enrofloxacin

Merriam Webster Online - World Chelonian Trust


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