Inexpensive Conventional Meds for Dogs

Summary: Although it is possible to do an all-natural regimen for dogs to prevent and treat fleas and worms, including heartworms, here is how some people treat their pets with OTC medications safely and inexpensively.

Heartworm prevention with ivermectin

NOTE: This is ONLY for prevention. A dog MUST have a negative heartworm test at the vet before using heartworm prevention. Once that it is done one can get a prescription for heartworm medication from that vet for Option 2 below but the test is also required for Option 1 since adult heartworms are not killed with ivermectin and they _will_ kill your dog if not treated at the vet. Treatment for adult heartworm infection is very expensive. It is necessary to use heartworm prevention year round and also to get an annual check at the vest to be sure.

Option 1

1% Injectable Ivomec, available on Amazon or at farm supply stores
UPC Propylene Glycol

Mix 30 parts propylene glycol and/or vegetable glycerin to 1 part injectable 1% ivermectin and dispense in 1oz dropper bottle. Use 1 drop per 3.667lb weight per month on food. SEE IVERMECTIN CALCULATIONS section below for detailed information.

The long term cost for treating a 100lb dog using the above method is about 6 cents per month, although the Ivomec should be replaced every 4 years.

Option 2

With a prescription, currently sells a 6 month supply of Tri-Heart Plus for about $20. This contains ivermectin for heartworm prevention and pyrantel pomoate for roundworm treatment and prevention.


Flea treatment with nitenpyram

Nitenpyram works in as little as 30 minutes and up to 24 hours to kill fleas. It also works in most cases for ticks. Note that fleas will fall dead off the dog, but may require brushing to remove. Ticks will continue to cling to the dog when they are dead and MUST be found and removed or skin will grow around them and the carcass will be impossible to remove. Nitenpyram does not prevent fleas - it just kills them once they bite the dog. Capstar is the expensive brand name drug for nitenpyram. Generic nitenpyram capsules on ebay are about 5-10% of the cost of Capstar. There are also flea treatments that last 30 days instead of 1, as well as a flea collar that lasts for months but is about to be recalled due to the number of dog deaths and neurological effects it has caused in humans, but I would not use these due to the potential side effects. Nitenpyram is generally safe to use as often as every day.


Flea prevention with botanical sprays

It is good to spray dogs with a bit of this before they will be in flea-infested areas such as forests with lots of wildlife, or dog parks. A good brand is Vet's Best Flea and Tick spray, which contains peppermint and other oils with a bit of soap. I prefer to use this as a preventative rather than a treatment since as a treatment it requires soaking the dog to the skin and it's still not as effective as nitenpyram, but a light spray on their coat will discourage most fleas and ticks from getting on them in the first place. It can also be used on shoes, socks, clothes, etc, to discourage bugs on humans when in the woods.


Flea infestation prevention

Lufenuron is a chemical that is given to dogs once per month. It does not kill adult fleas or prevent them from biting - it kills larvae and eggs so they don't multiply. The name brand is Capshield and costs about $10 per month. Generic versions can be found on ebay that cost about $5 per year although it is getting difficult to find plain lufenuron since it is mostly sold in a combination with nitenpyram. But you will still need to buy plain nitenpyram to have on hand if the dog gets a flea and it's been less than a month since they were given the combination.


General worms

Every three months it is best to deworm a dog with a broad spectrum dewormer which includes pyrantel pomoate and praziquantel. This is sometimes known as a 7 way dewormer since it treats 2 types of roundworms, 2 types of tapeworms, and 3 types of hookworms. It can also be known as a triple wormer since it treats three different types of worms. Note that if there is a known infestation of worms, this should be given again in three weeks. The best deal currently is probably Durvet Triple Wormer which is a 3 year supply for $46. The two chemicals can be had much cheaper at farm supplies and mixed in the correct ratio, but $15 per year is cheap enough to not have to bother.

However, this combination of chemicals does not treat a somewhat common dog parasite and that is whipworms. Fenbendazole can be used for that, as well as many other round, hook, and tapeworms. But fenbendazole is not effective against the most common type of dog tapeworm, unlike the 7 way dewormer. Plus it must be given 3 consecutive days. Panacur is the expensive name brand of fenbendazole powder. It does not look as expensive until you read the directions and realize that your dog may requre multiple pouches each day over the three days of treatment. Inexpensive fenbendazole is available as a goat dewormer on Amazon and at farm supplies. The dose for dogs is much higher than for that of goats (which is listed on the label). For dogs, it is 20mg per lb. Since the SafeGuard Goat Dewormer is 100mg/ml, the rate is 1ml for every 5lb. A 25lb dog would get 5ml (1 tsp) every day for three days. If a different concentration than 100mg/ml is used, adjust accordingly!


Ivermectin Calculations

This section is provided so people can follow the math on the amount of ivermectin to use when calculating the dilution ratio and dose for heartworm prevention in dogs. On web pages as well as reviews of 1% ivermectin, people said they asked their vet, or asked their pharmacist brother-in-law, or followed some legit-looking website, and therefore use an amount for their 100lb dog with enough ivermectin to treat an elephant. This is not a joke – you can find dozens of recommendations for dosing a 100lb dog for heartworm prevention as if it weighed 4400lb on recommendation of their vet. Luckily, ivermectin is safe for most dogs even in these huge amounts and in cases of mange, the dose is 50 higher than for monthly heartworm prevention, but is not necessary and in some breeds of dogs, lethal.

Injectable ivermectin is NOT injected for heartworm prevention in dogs. It is diluted 30:1 with propylene glycol and/or vegetable glycerin and drops of this mixture are put on dog food. However, it is necessary to use a sterile 1ml syringe with needle to remove the ivermectin from its bottle since it has a rubber seal that is not removed. This keeps the bottle sterile and it can last for years. Ivomec has a use-by date of 4 years from manufacture. Lesser quality solutions can be as little as 1.5 years. It should be stored in a cool place out of sunlight, like the refrigerator. Even with Ivomec treating a number of dogs, only a few ml of Ivomec may be used before it is ready to replace and you will probably be throwing out over 90% of the bottle when the 4 years is up.

Here is the amount of ivermectin in prescription heartworm medications, like Heartgard and Sentinel. Note mcg is microgram, which is 1/1000 of a mg or 1/1,000,000 of a gram.

1 – 25lb                68mcg
26 – 50lb              136mcg
51 – 100lb           227mcg

I think that a lot of people don’t know (or notice) the difference between a mcg or mg and/or think a milliliter (ml) weighs a milligram (mg) instead of a gram. Note that a cc (cubic centimeter) is the same as ml. Also note in the following that 1ml of ivermectin mixed with propylene glycol is assumed to weigh 1g, as if it were the same density as water. It is actually closer to 0.965g, but this is ignored to make the calculations easier. Besides this, there are also other errors in the analysis below, such as ignoring the difference between 51 and 50lb, or saying a 1oz bottle can hold 31ml when it might only hold 30ml. This is all an estimation that’s going to get you within a couple percent of the correct dosage.

1ml, or 1g, of 1% ivermectin = 1000mg. This is 10mg or 10,000mcg of pure ivermectin. At the rate of 227mcg per 100lb dog, this is enough to treat a 100lb dog 10,000/227 = 44 months. NOTE THAT MANY WEBSITES, PRODUCT REVIEWS, AND EVEN SOME VETERINARIANS ERRONEOUSLY recommend 0.1ml of 1% injectable ivermectin per 10 lb for heartworm prevention which is 1ml per 100lb when this is sufficient for a 4400lb dog. That’s right, a dog that weighs as much as an F150 pickup truck. THIS IS ENOUGH TO KILL collies, sheepdogs, shepherds, and other breeds that have ivermectin sensitivity. It may also be enough to injure dogs being treated with Comfortis (a once per month flea prevention with the active ingredient spinosad).

In the recommended dose of ivermectin from the chart above, a 51lb dog gets about twice as much ivermectin per pound as a 100lb dog. It is best to treat dogs with the amount as if it were at the bottom of the weight scale for that dose since it is might be a couple percent more effective. So, the recommend maximum dose for heartworm prevention is 227mcg/50lb or 4.54mcg/lb.

An easy way to dilute ivermectin is to get a 1 oz dropper bottle.  It holds about 30ml.  Almost fill it with USP propylene glycol, then add a measured 1ml of 1% ivermectin from a syringe. Note that once it is mixed, it must be shaken well, and the bulb squeezed a few times, to ensure that it is well mixed before dispensing each time. If it is being stored in the refrigerator, it should be warmed a bit before shaking since propylene glycol and especially vegetable glycerin is thicker when cold.

Now we have a solution that contains 1/30 = 0.033% ivermectin. Every ml (or g, or cc, or 1,000,000mcg) contains 333mcg. This is sufficient to treat a 100lb dog at the rate of 333mcg/month (min dose 227mcg/month from the chart above) for 30 months or 2.5 years. But to treat at the maximum recommended dosage, we want 454mcg for a 100lb dog per month, so this would be 22 months.

In a typical dropper bottle containing propylene glycol or other liquid about the same density as water, a single drop is 0.05ml, or 1/20 of a ml. Since the 30:1 solution contains 333mcg/ml, each drop is 333/20 = 16.65mcg of ivermectin.

The recommended maximum dose is 4.54mcg/lb and there is 16.65mcg per drop. This is 1 drop per 3.6674lb of dog. This yields the following chart. To calculate it yourself exactly, divide weight in lb by 3.6674. The following was done in a spreadsheet with the drops rounded to 0 decimal places.

30:1 Dilution of propylene glycol to 1% injectable ivermectin












































As of this writing in 2021, injectable 1% Ivomec cost $33 for 50ml on Amazon. USP propylene glycol costs about $12 for a pint. So each batch of this mixture will cost about $33/50 + $12/16 = $1.41. The monthly cost for a 100lb dog is $1.41/22 = 6 cents.

Another website that did the math for 1% injectable ivermectin correctly is They don't calculate their dosages for the maximum recommended but instead for a median value by weight, so the number of drops will be less.