Canine heartworm disease can be prevented using one of many safe daily or monthly preventative medications. Regrettably though, many dogs are not provided these drugs and become infected with this serious and life-threatening disease. Melarsomine is an injectable drug used in-hospital to treat heartworm disease in dogs. Treatment (not prevention) comes with risks, but not treating your infected dog is much more risky, and likely fatal. Treated dogs require 4-6 weeks of cage rest post-treatment. Melarsomine is administered by deep intramuscular injection in the lumbar (lower back) muscles.
WHAT IS THIS DRUG?
- An organic arsenical chemotherapeutic agent
- Given by deep intramuscular (in the muscle) injection at your veterinarian’s office
- Registered by the FDA for use in dogs
REASONS FOR PRESCRIBING:
- To treat dogs with stabilized heartworm disease caused by immature (>4 months old) and adult heartworms (Dirofilaria immitis)
WHAT DOGS/CATS SHOULD NOT USE THIS MEDICATION?
- Melarsomine should not be used in cats
- Animals with other diseases receiving treatment with Melarsomine will need intense monitoring
- Dogs with Class 4 disease should not be treated with Melarsomine until the heartworms are surgically removed from the vena cava (large vein carrying blood back to the heart)
- Safe use in breeding dogs has not been determined
- If unable to wait to treat, use with caution in a pregnant or nursing pet
- Animals with a known hypersensitivity or allergy to this drug
Heartworm disease is a serious condition as it can kill your dog if left untreated. It can be prevented with daily or monthly preventative medications (sometimes combined with flea, tick and other parasite killers).
The sooner heartworm disease is detected by a routine heartworm test, the better the chance for a full recovery.
Heartworm disease is graded Class 1-4, with 4 being the most severe.
Some dogs may have such a severe case of heartworm that they need to be stabilized with steroids and/or heart medications prior to administration of Melarsomine.
It is important that an accurate weight is used to determine the correct dose.
Melarsomine will be injected deep into the back muscle. A second injection will be given on the alternate side 24 hours later (for Class 1 and 2 cases). Class 3 cases may have an initial injection, wait 30 days and then have 2 injections as shown above.
Your dog will need to have his blood re-checked in approximately 4 months and may need a second course of treatment depending upon the laboratory test results.
Dosages and timing of treatment may vary with the other classes of heartworm disease.
This drug is given in-hospital in order that your pet receives the necessary patient supervision and to decrease the risk of complications.
Once your pet has returned home, keep him/her quiet (ie. cage rest) for 4-6 weeks to help reduce the risk of pulmonary embolism (an obstruction of a blood vessel in the lungs).
Discuss with your veterinarian how to prevent further heartworm infections by regular use of a preventative heartworm product.
WHAT IF A DOSE IS MISSED?
STORAGE AND WARNINGS:
Powder should be stored upright at room temperature.
Reconstituted powder (mixed with sterile water) should be stored in the refrigerator and used within 24 hours. Protect from light.
Keep this and all medication out of reach of children and pets. Avoid human exposure. Wear gloves when handling this product. Potentially irritating to eyes. Consult a physician in cases of accidental exposure by any route (dermal, oral, or by injection)
POTENTIAL SIDE EFFECTS:
- Rapidly killing large amounts of heartworms can have serious and fatal results
- Injection site reactions include pain, swelling and tenderness, or reluctance to move due to pain at the site
- Hard nodules at the injection site (may persist)
- Coughing, gagging, depression, fatigue, inappetance, fever, lung congestion and vomiting may be experienced. This may be due to the adult heartworms dying and obstructing the arteries in the lungs and causing other reactions. Supportive treatment with steroids may be necessary.
- Less commonly seen instances of drooling, panting, loose stools, coughing up blood, abnormal heart rhythms, and death
- Dogs older than 8 years of age seem to experience more depression, inappetance and vomiting than younger dogs
- If you observe any of these symptoms or you notice anything else unusual, contact your veterinarian
CAN THIS DRUG BE GIVEN WITH OTHER DRUGS?
- Yes, but possible interactions may occur if given with Caparsolate and glucocorticoids
There are risks using this drug. Damage to the lungs and kidneys may occur. Watch for drooling, panting, pacing, fever, vomiting, diarrhea, tremors, weakness, stumbling or difficult breathing which may lead to collapse, coma and death.
WHAT TO TELL/ASK A VETERINARIAN BEFORE GIVING MEDICATION?
Talk to your veterinarian about:
- When your pet will need to be rechecked
- What tests may need to be performed prior to and during treatment with this drug
- What are the risks and benefits of using this drug
Tell your veterinarian about:
- If your pet has experienced side-effects on other drugs/products
- If your pet has experienced digestive upset now or ever
- If your pet has experienced liver or kidney disease now or ever
- If your pet has experienced any other medical problems or allergies now or ever
- All medicines and supplements that you are giving your pet or plan to give your pet, including those you can get without a prescription. Your veterinarian may want to check that all of your pet’s medications can be given together.
WHAT ELSE SHOULD I KNOW?
In case you are also a cat owner, feline heartworm disease is incurable but 100 percent preventable with medications from your veterinarian. And don’t think your indoor-only cat is safe. A North Carolina study reported that 28 percent of cats diagnosed with heartworm disease were indoor-only cats. (veterinarypartner.com)
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