American Fancy Rat & Mouse Association

This article is from the Nov.-Dec. 1991 AFRMA Rat & Mouse Tales news-magazine.


Administration of Anthelmintic Drugs

By Kimberly Johnson, Animal Health Technician

It should be brought to the attention of rat and mouse owners that administration of an anthelmintic (drugs used to kill or cause paralysis and relaxation of the parasite in the intestinal tract, blood, and tissues) and insecticides (chemicals used to kill mites and lice) should be done so with great care! Even though great care has been made to ensure that these drugs are relatively safe, there is still a potential danger that the drug could have a toxic and even life threatening effect to the animal and cause an irritation to the human as well (if using insecticides).

Dichlorvos or otherwise known as “Task” (which has been removed from the market), Malathion, and Ronnel are examples of organophosphates. Organophosphates should not be used simultaneously with one another. For example, if you wash your rat with an agent that contains an organophosphate, don’t apply a powder or spray on the animal after its bath. This could cause a life threatening situation. Also, organophosphates should not be used with any other pesticides or muscle relaxers. Simultaneous use could produce Organophosphate poisoning. Signs of organophosphate poisoning would include Miosis (constriction of the pupil), salivation, difficult breathing, defection, and vomiting. By the way, only two animals that should not vomit are horses and rats. If they do, there is something seriously wrong! If your animal has signs of organophosphate poisoning within 5 minutes of administration, take the animal to your veterinarian immediately, and bring the chemicals you used on the animal with you. One known treatment that I know of is Atropine which can only be administered by a veterinarian. This counteracts the toxic effects.

Here are some guidelines you may want to follow when administering any type of external or internal parasite drug or chemical:

  1. Read the label! Follow the directions exactly. If it is not recommended for rats and mice, don’t use it unless the animal is under the care of a veterinarian.
  2. Administer the drug in the proper route—orally, IM (intramuscular), Sub Q (under the skin), topically (for sprays, dips, and powders).
  3. Avoid contact with your skin and eyes when applying sprays, dips, and powders. At the least, wear gloves to protect yourself. These chemicals not only absorb into your animals skin and could cause toxicity, they can absorb into yours!
  4. Avoid prolonged inhalation of foggers, sprays, powders, and dips.

Remember, always read labels first before you use any drug, whether over the counter or prescribed. By doing that you may just avoid any mishaps you might regret later.

Following are excerpts from Mosby’s Fundamentals of Animal Health Technology – Principals of Pharmacology, by Richard Giovanoni/Roger G. Warren, The C. V. Mosby Company, St. Louis, 1983:

  1. Young animals have little drug detoxification ability because they lack mature enzyme systems.
  2. Sex can be shown to influence drug detoxification rate—female rats metabolize drugs slower than male rats.
  3. An animal’s general health, age, and sex should be considered when a dosage regimen is being formulated.
  4. Studies of fetal drug levels during gestation are scanty and until more conclusive data have been presented, drug therapy in pregnant animals should be avoided whenever possible or at least kept to a minimum with respect to the number and types of drugs administered, their dosage amounts, and the duration of treatment.
  5. The kidney is the most important route of drug elimination.
  6. The rate of drug elimination depends on renal efficiency.
  7. Drugs used to treat diarrhea, parasitic infections of the gut, and constipation are not usually intended for systematic distribution. *

Updated April 9, 2014