ProHeart 6® Injection for Heartworm Prevention in Dogs

ProHeart 6 is a prescription injectable heartworm preventative for dogs. It provides sustained protection for six months with one veterinarian-administered dose. This page explains how the medicine works, who it suits, and how to order safely.

What ProHeart 6 Is and How It Works

ProHeart 6® contains moxidectin, a macrocyclic lactone that prevents heartworm disease caused by Dirofilaria immitis. The injection forms a depot under the skin that slowly releases medicine over six months. We offer US delivery from Canada to help you access Canadian pricing without insurance. CanadianInsulin.com is a prescription referral platform. We verify prescriptions with your prescriber when required, and licensed Canadian pharmacies dispense your order.

This treatment is administered by a veterinarian as a subcutaneous injection. It kills heartworm larvae (L3 and L4) acquired in the previous months and maintains protective levels to prevent new infections. Labeling also includes control of certain hookworms in dogs. For background on heartworm disease, see our overview of Canine Heartworm Disease. For hookworm information, see Canine Hookworm Infection.

Who It’s For

This medicine is for healthy dogs six months of age and older. Dogs should test negative for heartworm infection before starting the program. It may also help control specific canine hookworms identified on the label.

Do not use in dogs with a known hypersensitivity to moxidectin. Avoid in dogs that are ill, underweight, or have a history of severe allergic reactions unless your veterinarian advises otherwise. Safety in breeding, pregnant, or lactating dogs has not been established.

If your dog needs monthly alternatives instead, you can explore our broader category of Pet Medications for other options.

Dosage and Usage

The injection is administered by a veterinarian once every six months. A weight-based volume is injected under the skin, using only reconstituted product prepared for single use. Your veterinarian will determine the correct dose and schedule.

Give the first dose within one month after your dog’s exposure to mosquitoes typically begins, following a negative heartworm test. If switching from a monthly preventative, time the dose at the end of that monthly interval. Many owners choose a 6 month heartworm injection to reduce lapses due to missed monthly doses. If you prefer monthly chews, see Interceptor Plus for a broad-spectrum option.

Strengths and Forms

This treatment is supplied as a sustained-release injectable suspension that a clinic reconstitutes before administration. The active ingredient is moxidectin, a heartworm preventative in the macrocyclic lactone class.

Vials are single-use after reconstitution and are matched to a dog’s weight at the visit. Packaging and exact presentation may vary by lot and supplier. Many clients choose a heartworm 6 month shot to simplify care throughout the season.

Missed Dose and Timing

If a scheduled visit is delayed, protection may lapse. Reschedule the appointment as soon as you can and ask your veterinary clinic whether retesting for heartworm is advised before the next injection. A clinic may recommend an interim monthly preventative until the visit.

If a prior dose was late or missed, your veterinarian may retest and then restart the six-month schedule. Do not give extra doses or adjust timing on your own. If you completed an earlier heartworm shot 6 months ago, contact the clinic to review timing.

Storage and Travel Basics

You typically will not store this medicine at home. Clinics store, reconstitute, and administer it under controlled conditions. If you are transporting a sealed vial to your veterinarian, keep it in original packaging, protect from extremes, and follow any handling instructions provided with your order.

Store out of reach of children and pets. Do not use a vial that is damaged, expired, or improperly sealed. If reconstitution has occurred, follow the clinic’s handling and discard timelines. When traveling, carry your prescription details and your veterinarian’s contact information in case verification is required at the clinic.

Benefits

This class of preventative offers long-acting protection with a single veterinary visit every six months. It reduces the chance of missed monthly doses, which is a common reason for heartworm break-through infections.

The treatment also provides labeled control of certain hookworms. By combining sustained activity with clinic administration, it can simplify adherence, particularly for busy households that struggle with monthly reminders. Many owners prefer 6 month injectable heartworm prevention to streamline care.

Side Effects and Safety

Common effects can include:

• Injection site swelling or soreness
• Lethargy or decreased activity
• Vomiting or diarrhea
• Loss of appetite
• Itching or skin irritation

Serious reactions are uncommon but can occur. Signs may include facial swelling, hives, collapse, difficulty breathing, or pale gums. Seek immediate veterinary care if you notice severe symptoms after the clinic visit. Use caution in dogs with a history of allergic disease. Dogs should be tested for heartworm before receiving an injection; administration to infected dogs can increase the risk of adverse reactions.

Drug Interactions and Cautions

Tell your veterinarian about all medicines, supplements, and preventatives your dog receives. Combining macrocyclic lactones with other products in the same class may increase exposure. Use caution with drugs affecting P-glycoprotein, particularly in breeds with MDR1 variants. Your clinic can advise on flea and tick products that are compatible.

If your dog has had past reactions to injections or vaccines, discuss risk mitigation. Do not split vials, reuse partially reconstituted product, or administer at home unless your veterinarian explicitly directs and trains you.

What to Expect Over Time

After the clinic visit, the depot slowly releases medicine for approximately six months. Most dogs resume normal activity the same day, though mild soreness can occur at the injection site.

Your clinic may recommend annual heartworm antigen testing before repeating injections. Ongoing mosquito exposure and regional risk determine whether year-round prevention is appropriate. If you prefer a chewable program later, your veterinarian can help transition from a dog 6 month heartworm shot to a monthly product safely.

Compare With Alternatives

Monthly chewables suit many dogs and allow flexible scheduling. Ivermectin-based chews such as Heartgard prevent heartworm disease with a once-monthly routine. Topical preventatives can also cover other parasites; ask your veterinarian which spectrum is best.

If your dog needs a milbemycin-based option for monthly use, Interceptor Flavour Tabs Cats Dogs provide heartworm prevention along with intestinal parasite control. Your clinic can help compare spectra, dosing frequency, and administration preferences for your household.

Pricing and Access

Many customers choose Canadian pharmacy pricing with US delivery to manage annual prevention costs. You can review options, check availability, and compare across formats before you order. Some clients look up a 6 month heartworm prevention shot for dogs to minimize monthly purchases.

Final pricing varies by supplier, vial size, and prescription details. Checkout uses encrypted processing. Your clinic’s administration fee is separate from product cost and may vary by practice.

Availability and Substitutions

Availability can vary by strength and package. If a specific vial size is unavailable, your prescriber may recommend a suitable alternative or a monthly product with comparable spectrum. We do not guarantee restock dates.

Patient Suitability and Cost-Saving Tips

This treatment may be suitable for healthy adult dogs in regions with consistent mosquito exposure. It may not be appropriate for dogs with active illness, previous severe injection reactions, or positive heartworm tests.

Ask your veterinarian about multi-month planning so you can align wellness exams with the six-month schedule. Consider calendar reminders near the due date to avoid gaps. Ordering multiple doses for future clinic use is prescriber-dependent and may help reduce repeat fees where permitted.

Questions to Ask Your Clinician

• Is my dog a candidate based on age, testing, and medical history?
• Which parasites are covered in our area of travel and residence?
• How should I monitor for post-injection reactions at home?
• What is the plan if we delay or miss the next visit?
• Can this be used with our chosen flea and tick product?
• When should we retest for heartworm before the next injection?

Authoritative Sources

For detailed, official information, review these resources:

• Manufacturer details and product overview from Zoetis: Zoetis ProHeart 6 product page.
• Regulatory background on approved veterinary drugs from FDA: FDA CVM Green Book resource.

Order now and have your veterinarian administer at the clinic; we provide prompt, express, temperature-controlled handling when required. Medical disclaimer: This content is for informational purposes only and is not a substitute for professional medical advice.