Ok my research is throwing up some very inconsistent things.One thing I keep reading is how perfectly safe Advocate is. One site even claimed it was non-carcinogenic or non-cancer forming but this was not the official Bayer site.
Ok let's go through this and hope its not too complicated.
First off, Anglostrongylus vasorum or the French Heartworm is one of 4 main lungworms that can infect your dog.
Advocate contains moxidectrin and imidacloprid the first can be fatal and indeed cause poisoning and neurological issues if ingested and the latter is highly toxic to honey bees and mildly toxic to some birds. Imidacloprid is a pesticide and is used crops. However its use has been suspended in France and several other EU countries due to its effect upon honey bees and other wildlife.
Another name for moxidectrin is Ivermectin.
Panacur has the active ingredient Fenbendazole. The only usage I can find is as a dewormer. It has shown toxicity when ingested by certain birds and reptiles. I can find no toxicity evidence reported for cats.or dogs.
Milbemax is Mibemycin oxide and Prazquantril. The latter is a wormer and is also known as Drontal or Droncit amongst other names. This wormer has a 90% incidence of causing diarrhea and/or vomiting after being ingested. High doses can cause increased symptoms.
Milbemycin oxide is tolerated well by dogs even those with multiple drug resistance.
Interceptor is a Milbemycin oxime only preparation and only available in the USA.
The four types of lungworm are:
1) Anglostrogylus vasorum or French Heartworm
2) Oslerus osleri
3) Filaroides birth
4) Crenosoma vulpis
Noah's compendium states that:
ADVOCATE: only treats 1 & 4
PANACUR: only treats 2
MILBEMAX: reduces level of infection in 1 & 4
However the Merck Veterinary handbook srates that Fenbendazole treats lungworms 1, 2 & 4 and also protects against Giardia.
Now this is where it is complicated. Panacur is Fenbendazole. Intavets website who manufacture Panacur say it only treats the infestation of Oslerus osleri. If this is so then it is of no use against Anglostrongylus vasorum so why is this used in high doses to treat it if the manufacturer and Noah's both state it won't treat the lungworm that Advocate prevents?
Mercks state Fenbendazole will treat the lungworms listed 1, 2 & 4 so they believe it can treat the lungworm treated by Advocate.
So why does Panacur not state this on their packaging?
Now, quandary number 2 is that Merck state and I quote "Another option for prevention of canine A. vasorum is mibemycin oxime ...."
in other words Milbemax. However as it also contains Praziquantel which is a wormer it would be safer to treat with a Mibemycin only formula which is Interceptor but that's only available in the US.Milbemax manufacturers also only state that it "reduces the level of infestation of A. vasorum".
Furthermore, A. vasorum has a pre patent period of 40-49 days. This means symptoms will not show until 40-49 days after infestation. So technically a dog could and I make no claims to this, could be treated every 5 weeks with Advocate and still be within the pre patent period. As I am not a vet I don't suggest you do this. This information is only for reference.
It also means one could technically treat with the appropriate dose of Panacur or Milbemax within the pre patent period.
The most worrying thing about Advocate is that it attacks the central nervous system of the parasite. There are no publicly published studies that I can find which show the long term effects on the central nervous system of dogs routinely treated monthly over a life span.
I know Advocate affected the medicine used to stimulate the nerves in Tali's eye by suppressing the nerve. This was unscientific but the opthamologist concurred with the information I found out and suggested using Milbemax for lungworm prevention.
I hope I have made this easy to follow. Although Advocate is stated as a treatment and cure, Milbemax according to Merck is a.preventative and Fenbendazole or Panacur covers more types of lungworm.
Sorry this is long and sorry for spelling or grammar as I am typing know the phone.