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Diroban 25 mg/mL, 5 x 50 mg vials Rx

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Product Overview

How To Use

What’s in it?


Questions & Answers

Product Description

Diroban is an injectable powder that is sterile (25 mg/ml) to be used to treat heartworm disease in the following stabilized Classes: 1a, 2b, and 3c. It is intended for adult mature infections or immature (stage L5, 4 months) in canines.

Diroban is the only drug approved by the FDA in the United States for the treatment of heartworm disease in canines.

This product is available in the following vial sizes:
  • 5 x 50 mg
  • 5 x 2 ml water vials (sterile)

What is Diroban 25 mg/mL, 5 x 50 mg vials?

Diroban 25 mg/ml sterile powder for injection is indicated for the treatment of heartworm disease in dogs.

Who is Diroban 25 mg/mL, 5 x 50 mg vials for?

Diroban is intended only for use in dogs.

Why use Diroban 25 mg/mL, 5 x 50 mg vials?

Diroban is the only drug approved by the FDA in the United States for the treatment of heartworm disease in canines.

How does Diroban 25 mg/mL, 5 x 50 mg vials work?

Melarsomine dihydrochloride is considered to be an organic arsenical chemotherapeutic agent. Melarsomine has a molecule weight of 501.34 and is designated chemically as 4 - [(4, 6-diamino-1, 3, 5- triazon-2-yl) amino] phenyldithioarsenite of di (2-aminoethyl), dihydrochloride. It’s considered water soluble. It is rapidly absorbed after intramuscular injection. It is unknown of the precise action mode for D. immitis.



Active ingredient(s):

50.0 mg melarsomine dihydrochloride
33.75 mg glycine USP.
1 vial: when reconstituted with 2 mL of sterile water for injection (provided) contains 25 mg/mL of active ingredient

How is Diroban 25 mg/mL, 5 x 50 mg vials sold?

25 mg/mL, 5 x 50 mg vials of lyophilized melarsomine dihydrochloride with accompanying 5 x 2 mL vials of sterile water for injection USP

What are the side effects of Diroban 25 mg/mL, 5 x 50 mg vials?

The most common reactions to melarsomine dihydrochloride include:
  • Fever
  • Lack of appetite
  • Coughing
  • Vomiting
  • Gagging
  • Depression
  • Lethargy
  • Anorexia
  • Lung congestion
In rare cases during clinical trials (less than 2%) dogs exhibited panting and hypersalivation; these symptoms exhibited were severe in some cases and primarily occurred during the 30 minutes following injection.

Despite being pre-treated with an anti-emetic, one dog was observed vomiting after melarsomine dihydrochloride injections. Treatment and time resolved reactions that were adverse, except for a small number of site reactions from injection, also known as persistent nodules.

Injection site irritation was observed for some dogs during clinical field trials; this included symptoms like:
  • Tenderness
  • Pain
  • Reluctance to move
  • Swelling
Of all dogs treated with the medication, 30% had injection side reaction of some kind. These reactions were moderate to mild and took place between the first week and first month of treatment. Less than 1% of reactions were severe; take care to avoid leakage, or injections that are subcutaneous or superficial. There is a possibility that firm nodules will be ongoing.
  • Diroban is contraindicated for canines with extreme heartworm or class 4. These dogs are classified with Caval Syndrome (D. immitis present in the venae cavae and right atrium).
  • What special precautions are there?

    • Only administer Diroban via intramuscular injection in the lumbar or epaxial muscles (L3 to L5). NEVER INJECT INTO OTHER GROUPS OF MUSCLES. NEVER ADMINISTER INTRAVENOUSLY. Be careful not to inject superficially or cause leakage (refer to SAFETY).
    • This medication is only intended for use in dogs. There has been no determination regarding safe use for pregnant or lactating bitches.
    • Always keep medication away from children. Avoid exposure to humans. Wear gloves or thoroughly wash hands after touching this medication. Diroban may cause eye irritation; if you are exposed to it, use plenty of water to rinse the eyes thoroughly. If you accidentally ingest this medication in any form (injection, oral, or dermal) contact your doctor immediately.
    • Pulmonary thromboembolism (death of worms which may result in coughing, weakness, or fever) is a risk for any dog that has heartworm disease. Dogs who have serious pulmonary arterial disease could show more extreme symptoms due to an elevated risk, including possible death, hemoptysis, right heart failure, or dyspnea. Depending on heartworm disease severity, it may be necessary to restrict heavy to light exercise following treatment.
    • Healthy dogs that do not have heartworm may have no negative reactions to a first injection but could exhibit symptoms following a second. Closely monitor dogs both while being treated and within 24 hours following final injections.

    What to do if overdose?

    Contact your closest emergency pet hospital.

    How can I store Diroban 25 mg/mL, 5 x 50 mg vials?

    Store in a dry and cool environment. (15° - 30°C). After reconstitution, solutions should be stored under refrigeration and kept from light in the original packaging for 36 hours. Do not freeze reconstituted solution.

    Helpful Tips:

    Pharmacists are standing by to offer Pet Parent counseling regarding prescription medication purchased from Allivet before and after dispensing. Pharmacists on duty are available Monday-Friday, 9:30AM - 5:30PM EST and will be on call Saturday 12:00PM - 4:00PM EST for consultation.


    Use as directed by your Veterinarian.

    DOSAGE AND ADMINISTRATION : DIROBAN should be administered by deep intramuscular injection ONLY in the epaxial (lumbar) muscles in the third through fifth lumbar region. DO NOT ADMINISTER AT ANY OTHER SITE. Avoid superficial injection or leakage. Use a 23 gauge 1 inch needle for dogs equal to or less than 10 kg (22 lb) in weight. Use a 22 gauge 1½ inch needle for dogs greater than 10 kg (22 lb). Use alternating sides with each administration. If repeated administrations are warranted avoid injecting at the same lumbar location. Record the location of the first injection(s) in the patient’s medical record for future reference.

    Disease Classification: It is vital to classify the severity of heartworm disease to apply the appropriate dosage regime for DIROBAN (see INDICATIONS).

    Class 1 and 2:
    If necessary, dogs should be stabilized prior to treatment. DIROBAN should be administered intramuscularly in the lumbar (L3 - L5) muscles at a dose of 2.5 mg/kg twice, 24 hours apart (see Dosing Table). Four months following treatment, a second treatment series (2.5 mg/kg twice, 24 hours apart) can be elected taking into consideration the response to the first DIROBAN treatment and the condition, age, and use of the dog. Worms that were too young to be killed by the first treatment series, i.e., < 4 months, may be killed by a second treatment series.

    Class 3:
    Alternate Dosing Regime: Dogs with severe (Class 3) heartworm disease should be stabilized prior to treatment and then dosed intramuscularly in the lumbar (L3 - L5) muscles with a single injection of 2.5 mg/kg then approximately 1 month later with 2.5 mg/kg administered twice 24 hours apart (see Dosing Table).

    Dosing Table: Care must be taken to administer the proper dose. Accurately weigh the dog and calculate the volume to be injected based on the dose of 2.5 mg/kg (1.1 mg/lb). This is equivalent to 0.1 mL/kg (0.045 mL/lb). The following table should be used as a guide to ensure that the proper volume has been calculated.

    WEIGHT (lb)                                  2.2 / 4.4 / 6.6 / 8.8 / 11 / 13.2 / 15.4 / 17.6 / 19.8 / 22 / 44 / 66 / 88 / 110
    WEIGHT (kg)                                   1      2      3      4       5       6        7        8         9      10    20   30   40     50
    VOLUME PER INJECTION (mL)    0.1  0.2   0.3   0.4    0.5    0.6      0.7      0.8     0.9    1.0    2.0  3.0  4.0    5.0*
    *Limited data were collected on the administration > 5.0 mL at a single injection site.

    Preparation: DIROBAN should be aseptically reconstituted only with 2.0 mL of sterile water for injection (provided as 2.0 mL sterile water for injection USP). This provides 2.5 mg melarsomine dihydrochloride per 0.1 mL of injectable solution. Two 50 mg vials will be required for dogs weighing > 20 kg and 40 kg and 3 vials will be required for dogs > 40 kg and 60 kg. Use immediately. Reconstituted solution may be used within 36 hours if refrigerated and kept from light.

    Treatment Response: A baseline can be established pre-treatment by using commercially available in-office heartworm antigen test kits prior to treatment. Treatment response can be assessed best by heartworm antigen testing applied 4 months after treatment. A successful treatment is determined to be conversion from an antigen positive to an antigen negative status. In dogs with signs of heartworm disease, gradual improvement should be observed as the long-term effects of the heartworm infection resolve. Some dogs may have chronic effects that will not totally resolve.

    Concomitant Therapy:
    During the course of clinical field trials, DIROBAN was administered concurrently with anti-inflammatories, antibiotics, insecticides, heartworm prophylactics, and various other drugs commonly used to stabilize and support dogs with heartworm disease with no adverse drug interactions noted.

    Routine Prophylaxis: If the dog is not currently receiving commercially available heartworm preventatives, they may be administered consistent with label recommendations and re-exposure risk.

    Main Ingredients

    50.0 mg melarsomine dihydrochloride and 33.75 mg glycine USP. 1 vial: when reconstituted with 2 mL of sterile water for injection (provided) contains 25 mg/mL of active ingredient. 

    DIROBAN is provided as 5 x 50 mg vials of lyophilized melarsomine dihydrochloride with accompanying 5 x 2 mL vials of sterile water for injection USP

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