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Program is the cornerstone of the successful flea control program. It prevents development of breeding flea populations therefore preventing recognizable infestations. It also effectively targets 85% of existing infestations comprised of eggs and larvae.

Active Ingredient

The active ingredient that controls fleas in Program is lufenuron, a benzoylphenyl urea (BPU) derivative. BPU's have been tested since the 1970s for their activity on insects. All BPU's, including lufenuron, are classified as Insect Development Inhibitors (IDI's). Lufenuron is a component of both Sentinel and Program and is Guaranteed by Novartis Animal Health.

MADE IN CANADA , Lufenuron remains the only oral insect development inhibitor (IDI) available to control flea infestations. It has been available in Canada since 1994, and is currently marketed in over 30 countries worldwide.

Structural Formula of Lufenuron

Structural Forumula of Lufenuron


Mode of Action

Program inhibits chitin synthesis, polymerization and deposition within the flea. Chitin is composed of polymers (links of molecules in a chain) of amino sugars and functions in many areas of flea development:

  • Chitin appears in the egg case to prevent desiccation (loss of water/fluid).
  • Flea larvae inside the egg possess an "egg tooth" composed of chitin that is used during hatching.
  • The larval exoskeleton contains chitin for structural integrity and to prevent desiccation.
  • The exoskeleton of the adult flea contains chitin that provides sites for muscle attachment and protection against pathogens, mechanical rupture and desiccation. Chitin comprises 25-50% of a flea's dry weight.

By interfering with chitin deposition, lufenuron disrupts hatching and larval molts. Studies show that feces from adult fleas feeding on treated animals contains Program and is passed through to the environment. This flea feces containing Program proved lethal to existing larvae that ingested them, making Program 100% effective in preventing the development of the egg and larval stage of the flea life cycle. It is this specific mode of action that makes Program such an effective flea control method, as the adults present in an infestation make up only 5% of the total population. With eggs comprising 50%, larvae 35% and pupae 10%.

The Flea Lifecycle

The pet owner feeds Program to the pet with a full meal . After ingestion, lufenuron is completely absorbed from the stomach within 3 hours. Peak absorption is attained within 6-12 hours. It is deposited into the body fat of the pet and within 24 hours is 95% effective. 48 Hours after the oral dose it is 100% effective and remains at this level as long as subsequent monthly doses are given with a full meal.

Being highly lipophilic (having an affinity for fat), Program distributes in the adipose (fatty) tissues, then releases slowly back into the bloodstream at therapeutic levels for at least 32 days. During a blood meal (which the flea must take in order to reproduce) the female flea ingests Program, which is subsequently transferred to her eggs and is deposited in her feces.

Egg hatching is prevented when the flea's chitin-containing "egg tooth" and exoskeleton fail to develop. Another aspect of Program's action is its effect on fleas already in the environment. Larvae that may hatch from treated eggs (possibly due to the movement or feeding of existing larvae) die during the first larval molt due to disruption in their chitin formation. Existing larvae within the environment, or from eggs that were laid before the pet was put on Program, feed upon the flea feces containing Program, and also die.

Directions For Use

When recommending Program, veterinarians will discuss certain issues with their clients, and develop an integrated flea control program that will meet their needs. The use of Program for flea control should be conducted under the instructions and supervision of your veterinarian, and should take into account the following factors:

  • The life cycle of the flea.
  • The level of flea infestation.
  • The desired speed of control.

Flea Life Cycle Interaction

The length of the flea life cycle can vary tremendously based on temperature, humidity and time spent in the pupael stage. Under ideal conditions of 24° Celsius and 78% humidity, the cycle is completed in as little as 14 days. Without stimulation, fleas may remain inside the cocoon for 4-6 months or more before they emerge. It is important to realize that if fleas are seen by the owner due to a delayed pupael hatch, that this is not a break in efficacy. These newly hatched fleas were deposited in the environment before the pet was on Program and have remained dormant. Rest assured that once these fleas are exposed to Program they will not be able to reproduce.

Program administration breaks the flea life cycle by inhibiting egg and larval development. However, pre-existing flea populations continue to develop and emerge after treatment with Program begins. Based on clinical studies, this continued emergence of pre-existing fleas is most significant during the first 30 to 60 days.

If a flea feeds on an untreated dog or cat for three days, it regains the ability to produce viable eggs. Therefore, it's critical that all dogs and cats in a household be treated with Program if fleas are to be effectively controlled.

Flea Control Recommendations

Used alone, Program can effectively bring an existing flea infestation under control. However, some owners are not willing to have their pet suffer from fleas for as long as it takes them to die off on their own. To ensure owner satisfaction, conventional flea control products may be used in conjunction with Program for the first 4-6 weeks to establish adult flea control in an existing infestation where Program is introduced. Although every household situation cannot be anticipated, the following scenarios are those typically encountered by veterinarians.

No flea infestation Situation

The pet owner and veterinarian have seen no evidence of fleas.


  • Program should be administered to all pets in the home prior to the beginning of flea season, or preferably year-round. Your veterinarian will be able to advise you of the correct date to begin treatment with Program.
  • On-animal adulticides should be used only if the pet is exposed to adult fleas outside its normal environment.
  • Program administration with a full meal should continue for the entire flea season.

Mild Flea Infestation Situation

A flea infestation is considered mild if there is no evidence of flea allergy or flea bite dermatitis or if only small numbers of live fleas are found on the pet.


  • Program should be administered to all pets in the home. # A topical adulticide should be used to control pre-existing fleas emerging in the environment.
  • Vacuuming carpet and upholstery to stimulate fleas to emerge from cocoons and remove some from the environment. The pet's bedding should be washed.
  • Once the flea problem is under control (usually within 4-6 weeks), the on-animal product can be discontinued.
  • Program administration with a full meal should continue for the entire flea season.

Severe Flea Infestation Situation

A flea infestation is considered severe if the pet has evidence of flea allergy or flea bite dermatitis, if large numbers of live fleas are found on the pet or if fleas are biting people in the home.


  • Program should be given to all pets in the home.
  • An on-animal adulticide should be used to control emerging fleas.
  • Vacuuming carpets and upholstery stimulates fleas to emerge from cocoons and removes some from the environment. The pet's bedding should be washed.
  • Conventional premise adulticides, with IGR's, are used to kill pre-existing stages in the environment.
  • Even after environmental treatment, pre-existing pupae may continue to emerge. This occurrence is called the "Pupael Window" effect and is discussed in the section on FLEA BIOLOGY. In the most severe cases, a second application of environmental spray may be used according to label directions to curb extremely large emerging pupael populations.
  • Once the flea infestation is under control (usually within 3 months), the on-animal product may be discontinued.
  • Program administration with a full meal should continue for the entire flea season.

In all three of these situations - no adults are killed as a result of administering Program. It is critical that owners understand that Program inhibits the future development of the eggs and larvae (85% of the population) to prevent an infestation, but does not kill the 5% adults present.

The inconvenience of subsequent messy home and on-animal treatments is prevented by the regular administration of Program to pets by preventing fleas from developing in the home.


Program has undergone numerous safety trials to test its margin of safety at various doses in dogs. In addition, it has been available world wide in over 30 countries with no adverse reactions found. The reason that Program is so safe, is that Lufenuron has no reaction in mammals. Mammals do not contain chitin, so the molecule is absorbed and excreted without ever having been metabolized. As such it is safe in all mammals. Program has been tested at hundreds of times the label dose with no difficulties in mammals. Lufenuron has no effect on breeding animals, nor does it affect conception rates or litter size in breeding pets. It crosses the milk barrier and the placental barrier with no harmful effects to the unborn cats and dogs. They are, in fact, protected from continuing the flea life cycle by Lufenuron passed on from the mother's milk.

Program exhibits no drug interactions, therefore it has no ill effect on older pets, or pets with liver or renal problems, regardless of any medication those pets may be on for their medical condition. It does not affect diabetics or pets on antibiotics. There is no bio-accumulation so there is no chance of lufenuron "building up" in the pet and causing a problem in the long term.

Normal pesticides and other prescription drugs have to be tested for an LD50. This is the recognized dose in animals where the drug turns toxic in 50% of laboratory rats. It was not possible to establish an LD50 for Program.

Studies completed in pre-clinical trials for Program are:

  • Acute Oral Toxicity in Mature Dogs.
  • Two-month Oral Toxicity in Puppies.
  • Six-month Oral Toxicity Study in Young Dogs.
  • Reproductive Study in Pregnant Beagles.

And Program was proven safe in all instances.

Because of Program's safety index, true reactions have yet to be seen in Canada. Suspected reactions are typically a coincidence and do not repeat themselves on re-dosing of the medication. But if you are at all concerned about a reaction with a Novartis product please see your veterinarian or contact us directly. Difficulties that some pets experience are vomiting or diarrhea, and these are usually transient and passing. In the same way that some humans are unable to tolerate a relatively mild drug like ASA, some pets may be sensitive to a component of Program and may get the equivalent of an upset stomach. Ensuring the dose is given after the full meal is one way to relieve this. Another is to change the pet from the tablets to the suspension or vice versa in case it is the dosage form that is stimulating the vomiting reflex. This would be considered an off label application and such a change must only be done at the recommendation of your veterinarian. Sometimes a direct dosing of dogs with the tablet or cats with the suspension (forcing it directly down the throat) can stimulate the gag reflex and cause vomiting which is unrelated to the drug itself. If this occurs repeatedly you will need to alter your dosing method, such as mixing the dose with a meal or crushing the tablet to powder. In some cases you may want the veterinarian to administer the initial dose to ensure there are no problems.

Note To Owners Of Free-Fed Pets: If your pet has food available all the time and is allowed to "snack" all day (this is most common with cats) it is vital to the success of Program that you remove the food for the first half of the dosing day each month. Free-fed pets are typically not hungry enough to eat a meal sufficient in volume to ensure 100% efficacy. These pets should be fasted for the day and fed a nice supper, possibly with a treat mixed in, later in the day (preferably early evening). This will ensure they eat enough food at one sitting, and the dose can be given in complete confidence.

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