What happens if I give heartworm medicine to an already infected dog?

A "low positive" may mean a low adult heartworm burden. The preventive is to kill any immature heartworm (microfilariae). The doxycyline is to kill the wolbachia bacteria. This is an organism that lives within the heartworm parasite as a symbiont. This portion of the treatment lasts 30 days after which medication is given via injection to kill adult heartworm. Treatment is outlined at the link below. https://d3ft8sckhnqim2.cloudfront.net/images/pdf/HeartwormTreatmentGuide_PetOwnerColor.pdf?1561720859

In this case, the heartworm treatment would need to be continued, but it's not like the entire process needs to be started again. In most cases, this would call for an additional injection or two of the medication that kills the adult heartworm and continuing the heartworm preventative. The treatment may vary depending on the dog's case and the doing the treatment. I reccomend consulting with the vet doing the treatment for more information. I hope that helps and all is well with Charlie.

Heartworm medication should be given to a dog every month, but if a dog does have heartworm, it will take at least six months for a dog to test positive after being infected. I would have Holly checked for heartworm now so she can be put on a preventative if she is negative for it. I hope this helps!

If you are prepared to go through with the treatment and aftercare this dog will require and understand that there are rare complications that that could be fatal, then I say go for it. I've been through heartworm treatment with one of my dogs and it added several wonderful years to his life.

If it was Heartgard, there is no cause for concern. It is an extremely safe product and very difficult to overdose. If it was a different preparation of ivermectin, a double dose may not be cause for concern unless your dog is sensitive to it or carries the MDR1 gene. Typically, a non sensitive dog requires dosing around 2000mcg/kg before clinical signs become apparent. See your vet for an exam as soon as you can if you are concerned. Bring the container of ivermectin with you. Treatment for ivermectin toxicity is supportive in nature. Monitor for vomiting, excess salivation, ataxia (wobbly gait), dilated pupils or tremors.

These medications are safe to give together and do not negatively interact with each other in any way. The heart worm medication is very safe to give with most conditions, so I would not be concerned about giving it unless your vet specifically advised not to give it. Heartworm medication tends not to have any noticeable side effects, but Rimadyl may have some adverse effects. The biggest concern with Rimadyl is that it can cause stomach/intestinal damage. If you notice that Jenny has a decrease in appetite, vomiting and/or diarrhea, then it's best to stop the Rimadyl and contact your veterinarian for further advice. Otherwise, these two medications normally have no noticeable side effects and are relatively safe. I hope that helps and Jenny feels better soon.

Hello. Heartguard is generally considered very safe, even in a dog with a current heart worm infection. If there was a reaction due to the presence of heartworms, it is almost always some kind of pulmonary event. So, it is possible that he has just developed a sensitivity or had a one off reaction to the Heartguard. Do think about having Buster tested before giving another pill, & do try to remember to give it every 30 days. All heartworm medications do a great job, but only if doses are not skipped, especially for dogs living in warmer climates. And if he does not seem better tomorrow, please make an appointment with your vet to have things checked out. Thanks for using Petco Pet Education Center, formerly Petcoach.