Why you need to ask your vet about pet drug interactions & side effects

Discuss potential medication side effects with your vet

In the middle of a busy veterinary practice, many veterinarians may overlook an opportunity to discuss the possibilities of drug interactions and pet medication side effects. For example, many commonly prescribed nonsteroidal anti-inflammatory medications (NSAIDs) can sometimes cause digestive upset and/or liver/kidney problems in some sensitive pets. Corticosteroids like Prednisone can cause similar problems in some pets, as well as predispose pets to diabetes with prolonged use.

While a topic of debate, these risks are increased if Prednisone and nonsteroidal anti-inflammatory drugs are used together.

While potentially lifesaving, antibiotics can also cause allergic reactions from digestive upset to skin irritation. Some pets are sensitive to topical flea and tick medications, and in my practice I always administer topical flea and tick medication on a separate day from heartworm preventative medication or vaccinations, in order to lessen the burden on a pet’s immune system.

Whenever multiple drugs are prescribed it is always important for pet owners to ask questions, because veterinarians not only prescribe pet medication but are also dispensing these medications in private practice.

Do you have a question on potential pet medication interactions or side effects? Leave a comment below. 

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  1. We recently bought a black lab and are really excited. We just are unsure on what to do about vaccines and meds? Is there a preferred place to get it done? I think that is great advice to watch for allergic reactions when administering meds.

  2. I personally am a minimalist when it comes to vaccinations, as most pets are overvaccinated today, which may lead to all sorts of chronic allergic and immune mediated diseases. I would wait until puppy is 14 to 16 weeks old and get one modified live viral parvo/distemper vaccination, which should give years to life time of immunity. Rabies should be given a few weeks later, but not at same time. Best done at vet. Vet can also get pet started on heartworm medications and have stool checked for parasites, etc

  3. My little jrt was not eating, was sick once, had diarrhoea once and very lathargic. Took her to the vet and prescribed clavaseptin and metronidazole! Despite wanting to eat she just couldn’t. All tests normal. Referred to specialists all tests normal! Stopped medication early as found out the side effect of the meds were the same as what she was being treated for!!!!! After a week of not eating and 3 lots of iv fluids I stopped meds early and guess what…….she’s alot better. If I sussed out it was the meds why couldn’t the vet! If I had kept her on the pills and she was still not eating they were going to insert a feeding tube! The pills can cause lathargy, anorexia, nausea, etc. All what she was suffering!

    • So sorry Joanne to hear about your mishaps. Yes many of my traditional veterinary colleagues often lose site of the fact that prescription medications can cause side effects from diarrhea, loss of appetite, vomiting, etc but sadly often dont acknowledge it in their practices. Same with vaccinations, pesticide use, etc. Glad to hear your dog is feeling better

  4. michelle frankenberryApril 20, 2016 at 8:59 pm · Reply

    my brothers dog is on anti seisure meds. what kind of flea medication can he use?

  5. Can cats take albon and clindamycin at the same time

  6. Yes, but should be under care and/or guidance of your local veterinarian.

  7. Can I give my dog methocarbamol, rilexine and carprofen at the same time

  8. Hi,

    My golden retriever has dilated cardiomyopathy. One of the meds she takes is furosemide. As she also has osteoarthritis, we use Deramaxx to control her discomfort and pain. I’ve read mention of issues with raking these two drugs at the same time, and I’ve also read that there is a slim chance that Deramaxx can cause respitory problems. Should I discontinue the Deramaxx?


  9. HI Jackie. I would not discontinue the deramaxx, unless your local veterinarian treating your animal has advised that to you. I have not heard of this interaction between these two drugs in clinical veterinary practice, although anything is possible. I have not heard of this drug causing respiratory issues in dogs. Also if your dog is on long term deramaxx and/or furosemide, then periodic liver/kidney blood monitoring by your local vet is recommended. To answer Becky’s question above, I dont think there is a problem between the three drugs you ask about, but should be under the care and supervision of your local veterinarian for proper monitoring, etc

  10. My dog has had seizures so my vet prescribed phenobarbital. He has a sinus infection and head stopped up so he just prescribed Amoxcillian/Prednisolone for twice a day to get rid of it. It looks like it will last about 7-10 days. Hard to tell by looking at the bottle. Is this okay? Can he take these together?

    • I would follow your veterinarian’s prescribed directions and medications. I dont see a problem with this combination, however if any concerns come up, see your local vet

  11. Can I give my dog Nex Gard while taking Deramaxx?

    • While I dont use Deramaxx very much in practice, I am not aware of a drug interaction, as far as I know. However you could check with your local vet and/or a 1800petmeds pharmacist to be sure

  12. Can my cat take terbutaline and pimobendan at the same time?

    • I have not heard of a problem with these two drugs, although I have rarely if every used them together. I would check with a 1800petmeds pharmacist to be certain

  13. Is Temaril P ok to give my dog while he’s on a course of antibiotics? Thanks y’all! :)

  14. I have used temaril P with antibiotics quite frequently in practice without a problem.

  15. We took cat to the vet with what sounds like nasal respitory problem and we also noticed that right pupil is slightly more dilated. Our cat was given Rilexine 75 for sinus infection. After reading leaflet and looking at websites, nowhere can I find that this is correct thing to give for sinus infection. Is that correct antibiotic? Done 2 days so far and can’t see any side effects. Thank you

    • Rilexine is a brand name for the generic first generation antibiotic, long used in small animal veterinary medicine, known as cephalexin. While this antibiotic is safe, it is certainly not my first choice for a sinus and/or neurological infection, especially in cats

  16. I was supposed to give my 3 lb pom .5 ml of Mitotana 80 mg/ml Suspension. However, I had a new syringe and I accidentally gave her 2 ml. What should I do??

  17. Hi, my dog has been suffering with cluster seizures & just started Phenobarbital in addition to the Keppra he has been on for a year. Today, my vet gave my dog a Convenia injection for a minor believed flare up of pancreatitis. His seizures were getting better & seem to be increasing since getting the injection. Are there any known interactions between these drugs?

    • I am not fan of convenia injection for a supposed “pancreatitis” episode, although it is convenient. Drug interactions are rarely possible, as is the fact that convenia can rarely cause neurological reactions in very sensitive patients. It is also possible that your dog’s seizure disorder is just getting worse. A consultation with preferably a veterinary neurologist is recommended in your area if possible.

  18. My Lab mix has recently been diagnosed with Addison’s. Treatment with Percorten and Prednisone. I am concerned about giving and using flea and tick products, immunizations, and heart worm prevention products. Some research shows that they can cause stress and increase in symptoms of Addison’s. I gave Nexgard and Interceptor on different days and noted weakness in the hind legs several days later . This had cleared after starting Addison’s treatment. Do you have any advice or information? Thank you.

    • HI Debbie. All excellent questions. Any pet with a chronic immune mediated or hormonal disease may be at increased risk for reactions to either vaccinations and/or routine pesticides used in other patients in traditional, clinical practice. You may want to seek out the advice of a holistic veterinarian in your area. For a list of holistic or homeopathic vets, see www. AHVMA.org or http://www.drpitcairn.com

  19. My cat has an uri. He was given three daily doses of aminophylline. Now prescribed antibiotic baytril. Indications suggest drug interaction between the two. How long should I wait to give baytril dose to avoid drug interaction?

    • Time during the day does not matter when meds are given. The drugs interact if used in high doses and/or if used long term. I would check with your local vet on this, as I normally dont use Baytril for simple URI’s in cats, as there are many other approved choices out there for cats in this drug class.

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