Praziquantel

Praziquantel was developed by Bayer AG in Germany over three decades ago. It’s reputation as a parasite treatment has increased over time, including the World Health Organization. It is especially useful to the guppy breeder as a treatment for such internal parasites as taperworms and is known as the most effective treatment for gill and body flukes.Action (Tapeworms) Praziquantel is absorbed, metabolized in the liver and excreted in the bile. Upon entering the intestinal tract it acts on the tapeworm. Praziquantel works by increasing the parasite's cell membrane permeability. It allows mammals to digest the worm. This results in loss of intracellular calcium, massive muscle contractions, and spastic paralysis of the parasites, as well as damage to the schistosome tegument, followed by attachment of phagocytes to the parasite. This dislodges the parasite’s attachment to the intestinal tract and allows it to be eliminated in the feces of fish.. Within 24 hours, all the adult and immature tapeworms are eliminated in the guppy's feces. The larval tapeworms are not treated. We have no information on the action of the drug on flukes. However it is probably safe to say it has the same effect on flukes and other external parasites. It paralyzes them, causing them to fall off.

Effective Against

Most of the drugs commonly used to treat or control common nematode intestinal worms are ineffective in controlling tapeworms (classified as Cestodes).

Praziquantel is a parasite-control drug with strong activity against a number of different tapeworms. Praziquantel is also available in combination with pyrantel pamoate (which controls roundworms and hookworms) and febantel (which controls roundworms, hookworms and whipworms). It is sold as a dog and cat dewormer under the trade names of Droncit, Drontal Plus, Rintal and Vercom. Human formulation: Biltricide® (Bayer).

In the aquarium trade it is sold as PraziPond, PraziPro and is in Jungle Products called Pond Fizz Parasite Clear and Jungle Parasite Clear. Check the ingredient list on the Jungle products.

Praziquantel is the most effective treatment for flukes (Gyrodactylus spp. and Dactylogyrus spp.).

Praziquantel is also effective against intestinal nematodes, such as capillaria.

Treatment Regime (Tapeworms) Using Droncit / DrontalThis treatment uses the dog dewormer Droncit (Drontal in the U.S.). Each dog-size tablet of Droncit contains 34 milligrams of praziquantel. Each cat-size tablet contains 23 milligrams of praziquantel.

The recommended dosage is 100-250 mg/10 gal water or 100 mg/25 g food.

The author has dosed at 5.5 mg per U.S. gallon without harm to guppy fry or adults. The tablet was crushed and shaken in a small quantity of water. It was poured into the tank. A white dust settled on the bottom. This is mostly the product binder and not un-dissolved praziquantel. The guppies were left in the tank for 24 hours. The medicated water was then diluted with 40% fresh water. On the subsequent day the water was diluted with 20% fresh water, then again the third day after.

Because praziquantel does not treat the larval tapeworm, at least a second treatment is necessary 10 days after the first treatment. There are larvae buried in the guppy's tissue that develop after the treatment. So a third or fourth treatment may be necessary. There seems to be no rule governing how many treatments will be required to rid the guppy completely of tapeworms.

According to Doc Johnson, praziquantel has little or no effect on the nitrogen cycle.

Thomas Giovanetti in Discus Fish (Barron's), suggests a one- or two-hour bath at 15-20 ppm or 60-75 mg/gallon (3.8L). He also suggests dosing via food at 20-150 mg/kg (2.2 lbs) of fish weight for nematodes.

Praziquantel is very safe to use and has a wide margin of safety. Overdosed fish will begin to swim and breathe irregularly. The symptoms disappear when the fish is returned to undedicated water.

Shelf Life 5 YEARS

Storage: Store below 30°C (room temperature).

The Department of Fisheries, Government of Western Australia, provides a cure for farmed Koi that have Bothriocephalus acheilognathi (koi tapeworm) "The best wormer is praziquantel, available as Droncit dog worming tablets. The tablets should be ground up and added to a bucket of feed pellets dampened with vegetable cooking oil at a rate of 10 tablets per kilogram of food. The medicated pellets are fed to the fish over one day until they have eaten about 10 percent of their own bodyweight."

Treatment Regime Flukes Using Droncit or Drontal An aquatic biologist at the Dallas Zoo, Dave Schleser, provides the following treatment regime for flukes in the January 1992 issue of Aquarium Fish Magazine.

The bath he recommends was for goldfish, so you may want to test his recommended dosage against guppy culls before using it on prized fish.

It's standard procedure at most aquariums for treating all incoming freshwater and marine specimens.

"Dissolve the Droncit at a ratio of one canine tablet to 1 gallon (3.8 liters) of water. Don't worry if there is some white powder that doesn't dissolve that is the binder. It may get all over your fish but it's worth it.

Remove all fish from your aquarium and soak them in the Droncit solution for three hours. Be sure there is enough dissolved oxygen in the water for their long soak. Adding an air stone is desirable. If the fish show any signs of stress, remove them from the soak immediately.

While the fish are soaking, treat your aquarium. Remove the carbon from your filters and add 2 tablespoons of plain household bleach per gallon of water. Allow this chlorinated water to run through your tank with the filters on for two hours.

Next, do a 100 percent water change. Use a double dose of chlorine remover in your new tank water and test the water for chlorine before you put your fish back in. The chlorine will destroy your biological filter, so take appropriate measures to restore it (such as a sponge filter from an established tank). Test your water for ammonia and nitrite every couple of days for the next three weeks.

Dave cautions that Droncit will not kill anchor worms or fish lice. However, he strongly recommends the Droncit soak as a preventative for the flukes he feels are likely to be present."

Where to Get

Check the Internet for the availability of AQUARIUM SOLUTIONS® & POND SOLUTIONS™ Liquid PraziPro™, AquaScience PraziPond, or Jungle Parasite Clear. Jungle Labs has a product called Parasite Clear Tank Buddies that contains Praziquantel. Jungle Labs also makes a product containing Praziquantel called, Pond Fizz Tabs™ Parasite Treatment.

Praziquantel is also available in a dog dewormer from Bayer called Droncit. The same manufacturer has another form, Drontal, that includes additional chemicals to kill roundworms.