Insecticide poisoning in your dog:
Organophosphate and Carbamate Toxicity in Dogs:
Areas which are prone to flea and tick infestations tend to use various forms of insecticide (e.g., organophosphates and carbamates). But exposure to insecticides — especially after repeated or heavy applications of chemicals — may be toxic to dogs. These forms of insecticide poisoning affect both dogs and cats. If you would like to learn more about how it affects cats please visit this page in the PetMD health library.

Symptoms and Types:
Dogs exposed to toxic chemicals may not exhibit all of the signs of poisoning. In fact, sometimes insecticides will cause the opposite of these symptoms instead, but there will usually be some indication that the dog is not well. If you suspect that your dog is unwell because of exposure to insecticides, you will need to remove your dog from the toxic environment, or cease using the insecticides, and seek medical attention for it before the condition becomes dire.

The following are some of the symptoms of toxic poisoning:
Muscle tremors
Constricted pupils
Increased heart rate
Lack of coordination (i.e., trouble walking)
Respiratory failure (e.g., trouble breathing)

Toxic levels of carbamate insecticides like methomyl and carbofuran can cause seizures and respiratory arrest in your dog. Organophosphate toxicity, meanwhile, may lead to chronic anorexia, muscle weakness and muscle twitching which may last for days or even weeks. Someorganophosphate insecticides commonly used include coumaphos, cyothioate, diazinon, fampfhur, fention, phosmet, and tetrachlorvinphos. This same kind of poisoning can occur with agricultural, lawn and garden insecticide products. Organophosphate types of these products are acephate, chlorpyrifos, diazinon, disulfoton, fonofos, malathion, parathion and terbufos. Carbamate types of these products are carbofuran and methomyl. Organophosphate and carbamate insecticides inhibit cholinesterases and acetylcholinesterase, essential enzymes in the body. Cholinesterases are enzymes which break down acetylcholine, which is a neurotransmitter. Consequently, acetylcholine remains attached to the postsynaptic receptors of the neurons causing continuous, unending nervous transmission to nervous tissue, organs and muscles (smooth and skeletal). This causes seizures and shaking.

Toxicity can occur due to the overuse, misuse, or use of multiple cholinesterase-inhibiting insecticides; overexposure to insecticides in the surrounding home environment; or the intentional application of house or yard insecticides on dogs.

If your dog has been diagnosed as having toxic levels of insecticide in its system, your veterinarian will immediately stabilize and decontaminate your pet. Your veterinarian will also administer an antidotal treatment to your dog. You will need to give a thorough history of your dog’s health, onset of symptoms, and possible incidents that might have preceded this condition. If you know what type of toxin your pet was exposed to, or you have a sample of it, you should take a sample with you so that your doctor can better treat the poisoning. Your veterinarian will then send a sample of whole blood to a laboratory experienced in handling animal samples. A positive result is confirmed when cholinesterase in the blood is less than 25 percent of normal levels.

Insecticides to stay away from:
– Carbamates (Carbaryl, Methomyl and Propoxur)
– Organophosphates (Chlorpyrofos, Coumaphos, Cythioate, Diazinon,
– Dichlorvos, Dioxathion, Malathion)
Myasthenic weakness has been reported with 18 different antibiotics relative to Myasthenia Gravis (MG) such as:
– Neomycin
– Panamycin
– Streptomycin
– Certain Tetracyclines.
Drugs with P O T E N T I A L L Y adverse effects on neuromuscular transmission:
Note: There are several antibiotics listed that have the POTENTIAL for causing a problem. However, most specialists have used them in these patients with no untoward effects.
– Penicillamine
– ß adrenergic antagonists
– Propranolol
– Actazolamide
– Aminoglycosides
– Metoprolol
– Phenothiazine
– Gentamicin
– Atenolol
– Magnesium
– Amikacin
– Timolol
– Methoxyflurane
– Ampicillin
– Calcium channel blockers
– Phenytoin
– Ciprofloxacin
– Diltiazem
– Tropicamide
– Erythromycin
– Verapamil
– Interferon
– Imipenem
– Nifedipine
– Disomer of carnitine
– Pyrantel pamoate
– Amlodipine
– Diatrozoate meglumine
– Neuromuscular blocking drugs
– Antiarrhythmic medications
– Succinylcholine
– Procainamide
– Atracurium
– Quinidine

Here is a common scenario:
“A young couple with a 9 month old baby brings in their 1 yr old mixed breed dog because it has fleas. Physical exam reveals several fleas on the dog and some alopecia over the tail head. The Veterinarian treats the dog with Frontline Plus and sends couple home with a six months supply of the product.
One week later the fleas are still in the home and on the on the dog so they take their dog to another veterinarian. They tell the second veterinarian that they are certain the fleas are resistant to the Frontline and that the other veterinarian had sold them a worthless product. They can not believe that the dog still has fleas and even worse since they stopped letting the dog into the babies room the baby has gotten bitten by fleas. The second veterinarian runs a flea comb through the dog’s hair coat and recovers 10 cat fleas. Due to their size none of the fleas appear to be fully engorged and none of the females appears to be actively reproducing. This veterinarian explains to the owner that none of these fleas has been on the pet more than a few hours and certainly less than 24 hrs, since it takes female cat fleas at least 24 hours to become reproductively active. The Veterinarian further explains that the product (or any product) is not a repellent and does not kill fleas instantly but is intended to kill newly acquired fleas within 24 to 48 hours. Actually it appears the product is working correctly. The pet owner wants to know “Why are there more fleas now than a week ago?” The veterinarian explains that the fleas on the dog and the fleas on the carpet came from fleas eggs laid 3 to 8 weeks ago. The pet owners react by saying “that is not possible because the dog did not have fleas then”. The Veterinarian explains that most of the time (likely >90%) pet owners never see the first 2 to 3 fleas their pets acquire outdoors. The females then begin laying eggs within 24 hours and within a few days are laying 40 to 50 eggs a day. Fleas they are seeing now are actually the next generation. Therefore once you begin treatment you can expect to continue to see some fleas for a few weeks until all immature life stages have developed and fleas have emerged to be killed on the treated pet (Development Window). The pet owners then ask “Why did the fleas get so bad in the bed room?” The veterinarian explains that you removed the pet from the bedroom thinking incorrectly that the fleas were coming directly from the dog. The fleas on your dog do not jump off and on the dog. The fleas on the carpet in the bedroom came from pupae, which came from larvae, which came from20eggs laid 3 to 8 weeks ago. Those are newly emerged unfed fleas that had never been on the dog. Fleas lay their eggs on the dog and then the eggs fall off into the carpet. Places pets spend most of the time are where most eggs and ultimately fleas will be found. The reason it has gotten worse is because the “living flea vacuum”, the treated pet has been taken out of the room and all those emerging fleas are now feeding on the only remaining warm blooded hosts, you and the baby. Simply “let the dog back into the room”. The product did not fail; the failure was simply a lack of client education by the first veterinarian on the flea life cycle and performance attributes of the product.”