Pain after Heartworm Treatment

A reader writes in today:

Had our cocker spaniel treated 5 hours ago with his first shot.
For the past 5 hours, he can not get comfortable, fidgets, lays in unusual positions.

When walking, his right rear leg is toeing-in and his walks clumsily, often positioning that right foot too far under his body.
In just the last hour, he has started some toe-dragging with that right foot. Not severe, and he corrects upon moving further into the stepping process.

Also, he has started to drool excessively. Both ears are wet as if he drank from a flat bowl.

Have given him 2.5 mg Diazepam to try to make him more comfortable.

Forgot to mention … the vet had to stick him twice unsuccessfully and then changed needles and successfully administered on the third try.
Do you think he is just experiencing more pain than usual because of the three 'sticks' at the site, or should we be concerned that something else is going on?

 My Reply:

Please call your veterinarian and let him/her know what is happening.

The medicine in the treatment (Immiticide) can cause a lot of inflammation at the injection site. This can occur no matter how smoothly things go and how little it seems to bother the dog at the time.

This can range from being absolutely undetectable to a dog that is crying constantly with pain. Diazepam helps with anxiety, but has no pain relieving properties to speak of.

Please contact your veterinarian about this, as human 0ver-the-counter products can be harmful to your dog. However, it sounds very much like your dog needs pain medication.

The pain usually subsides in a couple of days, and most dogs don't have this type of reaction, but the ones that do get painful do need some help.

The difficulty in walking may indicate that the inflammation is causing enough swelling to put some pressure on a nerve root.  This can be very temporary, but certainly needs to be addressed.

Call your veterinarian and report this situation.  He/she will decide what anti-inflammatory or pain-controlling measures are needed to help your dog.  He/she can't help if they don't know about it.

17 thoughts on “Pain after Heartworm Treatment

  1. Heather says:

    I am total agreement. When my dog Chester was successfully treated with Immiticide last year, he was given a full course of prednisone for joint inflammation and pain. It did wonders. Unfortunately, the drug that’s used (Immiticide) is a form of poison and pain management is important here. Your vet should be made aware of what you are observing so that his pain levels can be addressed.It’s a tough row to hoe, but when it is all done, it’s wonderful!

  2. Doc says:

    Hello, Elizabeth and Crew,

    I also am amazed. Most of my replies advise these folks to let their veterinarian know what is happening. When we don’t hear from the client, we think everything must be okay.

    We try to call our clients back in a day or two to see how things are going. It blows my mind when they are having much worse problems, but didn’t call us to let us know.

  3. Pet Supplies Online says:

    According to my opinion heartworm disease is completely preventable. A number of different products with excellent safety profiles are available. Tragically, some studies indicate that a minority of dogs and cats receive the preventatives as they should. Animals in the majority now are at even greater risk.

  4. sally webster says:

    I am glad I found this page. My lab just had her first treatment today and she is very restless and only lays down for a few minutes at a time, she is very careful getting up to stand and very slow to lay back down. She has not eat anything since I picked her up from the vet. They did give her tramadol to give 2 pills every 8 hours for pain and 2 benadryl, It seems to help a little but not much. I have cried all evening thinking I have done the wrong thing by having this heartworm treatment done. I had a little dog that had heartworm treatment done 7 years ago and he died,I was very scared to do this with my lab. But the vet said she had to have it done and she is 3 years old and should do well, my Fred was 9 and a half years old and a cocker mix. I still feel the guilt of choosing HW treatment for him and I miss him still. I have prayed for Annabelle to be ok through this.

  5. Doc says:

    Hello, Sally,

    I suspect by this time that your dog is feeling better. The soreness rarely lasts more than 24 to 48 hours.

    You might ask your veterinarian about increasing dose or frequency. We usually give one 50mg Tramadol tablet per 20 pounds of body weight, up to four times daily, if needed. Dogs absorb Tramadol poorly, so require much larger doses than people of similar size.

  6. Valerie Victoria says:

    I am rescuing a whiten terrier from a no kill shelter he tested positive for heartworms anf has had his first treatments unfortunately he is not doing so well with his mobility with his back legs the vet tech seems to think it could be a underlying condition such as a tumor, because usually dogs will regain strength within a couple of days of treatments he has not. He is eating and drinking has anyone had an experience where there pet took longer to gain strength

  7. Doc says:

    Hello, Valerie,

    Even with dogs that have had very severe pain, all of my patients have gotten back to normal within 2 or 3 days. If your dog is having problems for longer than that, he should be evaluated by your veterinarian.

  8. Deborah Wright says:

    I have a small Terrier that I took possession of
    Taking her to get neutered and shots, found she tested positive for heart worms
    Her first shot, in 24 hours she was much better off
    Now she faces the second shot
    She is a little over a year old
    Can I do compresses or ??? To help ease the muscle pain ???

  9. Doc says:

    Hello, Deborah,

    Cool compresses may help. You should ask your veterinarian about pain medications to help. We do this routinely with our heartworm treatment patients. Some don’t seem to need it at all, but others can be quite painful.

  10. Kathleen Mendel says:

    My little rescue from San Antonio Texas tested positive for heart worm even though he was negative when we adopted him. He is just finished his first injection today and is very restless; repositioning himself every couple minutes. Given him tramadol but apparently not helping. I am a nurse, the way he is acting looks like patients that are going through withdrawals from chemical addiction. I wish I could ease his discomfort. Fearing tomorrow as he will be getting second injection:(

  11. Meghan says:

    My rescue just had the two injection slow kill done. I’ve had him home for an hour and he seems pretty calm laying outside but after ten minutes he wants back inside. However, inside he keeps getting up and repositioning every few minutes and crying. The vet said to start all his meds tomorrow morning. What can I do to help with his discomfort? I would try ice or a warm towel but there is no bald spot so I’m not sure where the injection was done.


  12. Doc says:

    Hello, Meghan,
    Sorry I didn’t get to this earlier. I hope your dog is feeling better now.

    The injections are usually given in the heavy muscle of the lower back.

    A cold pack (not actual ice) would probably have been good. I usually send home Tramadol. Since we give them a cortisone type drug, we can’t use things like Rimadyl (NSAID – non-steroidal anti-inflammatory drug), as they don’t play well together.

    Sorry I got behind.

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