2016 Merck Advanced Medicine Symposium - Audience Q&A from WVC

2016 Merck Advanced Medicine Symposium - Audience Q&A from WVC

The following are the speaker responses to questions from the audience during the Symposium sponsored by Merck Animal Health held Tuesday, March 8, 2016 at WVC in Las Vegas, NV.

The opinions expressed in these answers are those of the speakers and do not necessarily reflect the official label recommendations and point of view of the company or companies that manufacture and/or market any of the pharmaceutical agents, products, or services mentioned.

Parvovirus Pediatric Critical Care: What’s New


  1. What is AZO in the Big Four?
    Dr: Lee: AZO, measured with Azostix® reagent strips, represents a gross measure of blood urea nitrogen (BUN).
  2. Do you double your ongoing losses if they are not measured?
    Dr. Lee: I don’t “double” the ongoing losses but grossly quantitate the amount lost and give that back intravenously (IV).
  3. Should antacids be used to reduce esophagitis due to vomiting?
    Dr. Lee: In general, antacids are benign but I personally feel that they are overused in veterinary medicine. If you suspect esophagitis or gastritis, sure, it is fine to use an antacid, but it has no antiemetic effect, which I feel is more important.
  4. Do you recommend against or for Convenia® injectable in parvovirus cases?
    Dr. Lee: I prefer Convenia (cefovicin sodium) only for outpatient treatment of parvovirus cases, not in-hospital cases (as it is not a potent enough antibiotic for gram-negative infections).
  5. What are your thoughts on fresh frozen plasma as part of treatment?
    Dr. Lee: Fresh or fresh frozen plasma (FFP) from recovered dogs has been suggested in the past to provide anti-parvoviral antibodies, but recent studies have not found a beneficial effect. These studies found that even recently recovered animals have minimal anti-parvoviral antibody concentrations (references available from Dr. Lee). Moreover, such treatment may prime the dog for future transfusion reaction at a later point in its life. In my opinion, transfusions are not benign and have pro-inflammatory cytokines that can result in acute lung injury, circulatory overload, etc. Again, as the literature has not shown FFP to be beneficial for parvovirus, I am not a fan. I have saved hundreds of parvovirus patients without using FFP; Ijust reach for a synthetic colloid instead. I would use FFP only if my patient was coagulopathic with a prothrombin time/partial thromboplastin time (PT/PTT) > 25% of the upper range.
  6. When using a nasogastric tube do you aspirate first and then feed the dog or just feed?
    Dr. Lee: I would aspirate initially to make sure there is not a large amount of gastric residue content left from ileus. If there is a large amount, I would recommend adding a prokinetic (eg, metoclopramide) and evacuating the stomach. I would also subtract that amount from how much you feed and consider either a constant-rate infusion (CRI, vs syringe pump) of feeding into the nasogastric tube, or smaller amounts more frequently.
  7. Can you address the use of Tamiflu® for canine parvovirus?
    Dr. Lee: I do NOT recommend the use of Tamiflu for canine parvovirus as there is no evidence for it. There have been numerous studies evaluating different “antidotes” for parvovirus. Equine endotoxin antiserum, recombinant human granulocyte-stimulating factor (rhG-CSF), or anti-virals (eg, Tamiflu) have not been shown to be effective in improving survival or outcome (references available from Dr. Lee). In small studies, the use of feline interferon has been weakly associated with improved survival; however, this is not readily available in veterinary hospitals (references available from Dr. Lee).
  8. Can we use Convenia in these cases? Will Cerenia® provide enough analgesia?
  9. Dr. Lee: I prefer Convenia only for outpatient treatment of parvovirus cases, not in-hospital cases (as it is not a potent enough antibiotic for gram-negative infections). In my opinion, maropitant (Cerenia) is not a true analgesic so I don’t use it for this purpose. It may provide minor analgesia. I generally don’t use pure mu analgesic opioids in these parvovirus patients, however, as I don’t think they are “acutely” painful (vs just severely nauseated and dehydrated, which responds to antiemetics and fluid therapy alone). If anything, I might consider buprenorphine if you are concerned about pain.
  10. What dose do you use for subcutaneous fluids?
    Dr. Lee: The Colorado State University (CSU) study I discussed used 30 mL/kg QID. I prefer fewer “pokes” and would ideally do 50 mL/kg BID‒TID as needed. Obviously, subcutaneous fluid administration depends on how much elasticity a patient has and generally can’t be done in Greyhounds or Boxers with thick muscling and little elasticity (at least for adult dogs).
  11. I have been using trickle feeding with Gatorade hoping it is better tolerated than CliniCare®. What are your feelings? Do you have your staff regularly aspirate the nasogastric tube if there is evidence of ileus?
    Dr. Lee: I would try Pedialyte® instead as it is likely more effective at electrolyte replacement. You can always dilute it with CliniCare if needed. See question #6 for my answer about aspirating nasogastric tubes.
  12. Do cats get parvovirus? Why does it seem to be getting worse? I live in cold weather and see more parvovirus than ever before.
    Dr. Lee: Cats can get parvovirus experimentally, but typically no. Cats get feline panleukopenia instead.
  13. What about using partial parenteral nutrition (PPN)?
    Dr. Lee: If the gut works, use it. PPN is great, but ideally nutrition should be given enterally if the patient is tolerating it.
  14. Is vaccinating at 8, 10, and 12 weeks enough?
    Dr. Lee: No. As discussed in my lecture, at-risk breeds should be vaccinated starting at 5 to 6 weeks of age, every 3 to 4 weeks, until 20 to 22 weeks of age.

Insulin Therapy in Diabetic Dogs and Cats

  • Patty Lathan, VMD, MS, DACVIM
  • Are there any available treatments for diabetic neuropathy in cats (for instance dropped hocks), other than insulin?
    Dr. Lathan: As far as I know, nothing has been proved to help; however, anecdotally, some people think cobalamin at 250‒500 micrograms subcutaneously (SQ) once weekly for 6 week) has helped. I have not tried it.
  • How long are you willing to keep detemir?
    Dr. Lathan: Six months, as long as it does not turn cloudy or change colors.
  • What is the cost difference between Vetsulin® and ProZinc®?
    Dr. Lathan: Our cost per 10 mL bottle (40 U/mL for each) is around $25 for Vetsulin and $70 for ProZinc. Obviously, client cost is different depending on markup.
  • What is the best way to transition a dog from NPH to Vetsulin?
    Dr. Lathan: I am guessing that three internists would give you four different answers to this question. It really depends on the individual patient, how regulated they are, and what dose of NPH they are on (ie, a high dose versus a low dose). In general, if they are on over 0.5 U/kg NPH, I’d probably start at 0.5 U/kg of Vetsulin. That is generally the safest approach to avoid hypoglycemia. If they are on a much higher dose of NPH (eg, close to 1 U/kg), I might split the difference and go to 0.75 U/kg Vetsulin.
  • If I were switching in the other direction (Vetsulin to NPH), some people use the rule of dropping the dose by 10% to 20%, but I still honestly usually start back around 0.5 U/kg, as long as the dog is already above 0.5 U/kg of Vetsulin. NPH is more potent (more rapid onset, shorter duration, so potentially more effect during that shorter duration), so you definitely need to be careful. Someone asked me a question about this at the end of the talk, and I might have said what I meant backwards. 
    How do I manage to do a glucose curve with Vetsulin? I am asking because of the two peaks of activity. I may have gone to BID treatment when I shouldn’t have.
    Dr. Lathan: I start at 0.25 to 0.5 U/kg BID; I never start once a day. If the patient is just reaching their nadir at 12 hours, however, switching to once daily would be reasonable.
  • If a cat is aggressive with the owner, would you ever use oral meds such as glipizide?
    Dr. Lathan: Definitely, although I suspect I can inject an aggressive cat more safely than I can pill them. But if the cat will eat glipizide in a pill pocket, and the owner can’t get close enough to inject, I don’t think you have a choice. Just make sure they understand that most cats don’t respond to glipizide adequately.
  • I have a cat on glargine that has been well controlled for 3 weeks but has significant neuropathy. How long does it last? Is there anything else I can do?
    Dr. Lathan: Diabetic neuropathy over improves, with good control, over a few months, but doesn’t always resolve. Anecdotally, B-12 injections might help (see question #1), but I have not used them and don’t know of any studies evaluating this.
  • Update on Demodex

    Wayne Rosenkrantz, DVM, DACVD

    1. Are Advantage Multi® or SulfOxyDex® baths still an option?
      Dr. Rosenkrantz: In my experience, Advantage Multi (imidacloprid + moxidectin) can be effective in mild cases of demodicosis when used more frequently, off label at weekly to every 2 weeks. It does not work as well as the newer options discussed. SulfOxyDex contains benzoyl peroxide, which can have benefits as an adjunctive treatment for demodicosis due to its follicular flushing effects.
    2. Is a biopsy more sensitive to diagnose Demodex than a scraping or just complementary to it?
      Dr. Rosenkrantz: Biopsies can aid in the diagnosis of Demodex in situations where marked scarring is present or in the Chinese Shar pei breed due to their mucinosis condition. Biopsy is more sensitive than skin scrapings but is rarely needed to make the diagnosis.
    3. Plumb’s Veterinary Drug Handbook recommends increasing the dose of ivermectin to 0.6 mg. What do you think?
      Dr. Rosenkrantz: Most cases of demodicosis do not require doses of ivermectin this high to respond. The majority respond at doses of 0.3 to 0.4 mg/kg/day. In the more refractory cases, you may need to go to dosages of 0.6 mg/kg/day but I do not start at this dose.
    4. How do you treat pruritus when antihistamines fail?
      Dr. Rosenkrantz: Pruritus in cases of demodicosis is often due to secondary pyoderma, so the initial focus should be on controlling infection first. If antihistamines fail after antibiotics, then of the three other major antipruritic drugs—steroids, Apoquel® (oclacitinib tablet) and Atopica® (cyclosporine)—I would select Atopica as I have not seen demodicosis as a result of use of this drug. However, I have seen demodicosis related to Apoquel and steroid use.
    5. What timeframe do you recommend for stepping up dosages for ivermectin? I work in a shelter so time is of the essence. I am moving it up every day, is that bad?
      Dr. Rosenkrantz: If you are going to utilize increasing dosing, most recommend stepping dosages up on a weekly basis—for example, 0.1 mg/kg/day for 7 days then up to 0.2 mg/kg/day for 7 days, then up to maintenance at 0.3 mg/kg/day. I do not typically do stepping-up dosing and just start at 0.3 mg/kg/day.
    6. How do you use Bravecto® (fluralaner) in growing puppies? Do you dose at the current weight knowing it will outgrow the dose in 3 months?
      Dr. Rosenkrantz: In young large breed dogs, I would typically use NexGard® (afoxolaner) to avoid issues about outgrowing the correct dosage.
    7. How long after using Mitaban® (amitraz) / ivermectin / Trifexis® (spinosad + milbemycin oxime) / Comfortis® (spinosad) can you start Bravecto or NexGard?
      Dr. Rosenkrantz: Bravecto or NexGard can be started immediately; there is no overlap in toxicity or drug interactions to worry about
    8. Can you and have you used Bravecto and ivermectin concurrently?
      Dr. Rosenkrantz: Yes, I have seen cases referred in on both medications but in my experience there is no need to use these together since Bravecto works so well by itself.
    9. What are the dosages for NexGard and Bravecto for demodicosis?
      Dr. Rosenkrantz: I use both medications at their recommended labeled dosing for flea and tick control.
    10. Are NexGard and Bravecto equally effective?
      Dr. Rosenkrantz: Yes in my experience both drugs work incredibly well and I haven’t seen one drug be superior to the other.
    11. What is the label dose for Bravecto and can you give it to a puppy under 6 months of age?
      The label dose is the same as what is used for flea and tick control. I have used Bravecto in puppies less than 6 months of age; this is off label use but I have not seen any problems. NexGard has a younger age on its label (8 weeks) so this is an option for puppies less than 6 months of age.
    12. How do you dose for the treatment of scabies? When do you repeat the scrape?
      Dr. Rosenkrantz: Labeled dosing is effective—for Bravecto, one dose and for NexGard, usually two doses. You can repeat skin scrapings if pruritus is not resolved after 4 to 6 weeks
    13. Is there anything in this class of drugs for cats?
      Dr. Rosenkrantz: There is research ongoing to evaluate isoxazolines in cats but there are currently no products available or approved.
    14. Does Goodwinol ointment work for local spots?
      Dr. Rosenkrantz: It can work but typically is irritating and often creates a larger patch of alopecia over the treated sites so I do not recommend its use.
    15. Can you rely on Bravecto for scabies treatment in light of potential zoonoses?
      Dr. Rosenkrantz: Yes, it appears to work very well but the number of cases treated to date are limited and no larger scale studies have been published.
    16. Does this class of drugs work on ear mites?
      Dr. Rosenkrantz: Yes, isoxazolines appear to work well for Otodectes at the recommended dosing for flea and tick control.
    17. Can you use this class of drugs with concurrent heartworm prevention?
      Dr. Rosenkrantz: Yes, heartworm preventatives can be used safely with isoxazolines.

    CIV Outbreak in Chicago: Lessons Learned – A Practical Review

    Melissa Bourgeois, DVM, PhD, DACVM
    Presented with Natalie Marks, DVM and Steve Dale, CABC

    1. Do you vaccinate with both H3N2 and H3N8 at the same time?
      Dr. Bourgeois: Yes, you can vaccinate with both at the same time, preferably in different locations.
    2. Should influenza vaccines be incorporated into all vaccine regimens or can we start with higher risk patients?
      Dr. Bourgeois: All dogs are at high risk of respiratory disease if they are social. This can include going to the dog park, walks in the neighborhood, going to the vet clinic, and boarding (to name a few). Any social dog should be vaccinated for influenza.
    3. It was mentioned that cats can get CIV. Can they pass it to the feral population and then back to the canine population?
      Dr. Bourgeois: We don’t know what amount of virus or for how long cats can shed. All we know is that when they are exposed to dogs with H3N2 they can catch it. Recent developments in a shelter environment where four group-housed cats were positive for H3N2 suggest they may be able to spread it among other cats.
    4. Can you speak about timing and known sensitivity of testing for patients presenting clinically? We wouldn’t be testing virus shedding without symptoms.
      Dr. Bourgeois: This depends on the pathogen. For H3N8, dogs will only shed about 3 to 5 days after the onset of clinical signs. This is true for some other viruses (shed less than a week) including parainfluenza, pneumovirus, and respiratory coronavirus. H3N2 can be shed for up to 24 days, but shedding may be intermittent. Bottom line is the earlier you can test after the onset of clinical disease, the better. If you are within a 3- to 4-day window of the start of clinical signs, you should be able to pick up most pathogens.
    5. What is the cost of diagnostics?
      Dr. Bourgeois: This depends on which lab you are using; I recommend that you contact that lab for this information.
    6. Will there be a vaccine that incorporates both strains?
      Dr. Bourgeois: With conditionally licensed vaccines, both strains of flu could not be combined. We know that clinicians want a vaccine with both strains and we are looking into it.

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