ALAT Chapter 12 Medications.pdf

ALAT Chapter 12 Medications Animal facilities use different types of drugs to ensure the animals’ health and to minimize pain and distress during procedures. For example, anesthetics and analgesics alleviate or prevent pain, and other drugs fight infections or kill parasites. This chapter describes...

ALAT Chapter 12 Medications Animal facilities use different types of drugs to ensure the animals’ health and to minimize pain and distress during procedures. For example, anesthetics and analgesics alleviate or prevent pain, and other drugs fight infections or kill parasites. This chapter describes several types of drugs, their general use, and how they are administered to the animals. This chapter only discusses drugs prescribed or used by the veterinary staff for clinical purposes. • The veterinary staff prescribes appropriate drugs for each animal. • Drugs specified in an animal protocol are selected in consultation with a facility veterinarian prior to the approval of that protocol. • These drugs must be used for each animal on the study, unless the veterinarian prescribes a change in medications or a change in the protocol is approved by the IACUC. • All personnel responsible for drug administration must be properly trained. • The consequences of giving the wrong amount of the drug or using an incorrect route of administration can result in illness or even death of the animal. • It is important to remember that the same drug may cause different effects in various species due to their unique physiological characteristics. For example, cats are very sensitive to the effects of opioids and NSAIDs, and some antibiotics can be fatal if given to guinea pigs, but are not harmful to most other species. Types of Drugs The following list describes commonly used types of drugs and their applications. A drug may be known by its generic (chemical) name or its brand name. For example, acetaminophen is the generic name of the brand-name drug Tylenol®. Different manufacturers may produce the same drug but sell it under a different brand name. Thus, the same drug may be known by several different brand names. Analgesics • Analgesics are pain relievers. There are two main categories of analgesics: opioids and nonsteroidal anti-inflammatory drugs (NSAIDs). • Opioids and NSAIDs relieve pain through different mechanisms and are associated with different side effects. It is important to choose the most appropriate type of analgesic because opioids or NSAIDs may affect the experimental outcomes of some studies. • Opioid analgesics are often referred to as narcotics. Morphine is a common example of a drug in this category. However, its use is limited in laboratory animal medicine since longer-lasting opioids are now available. Buprenorphine is an opioid that is commonly used in laboratory animal medicine and is generally safe in many species. Opioids work by affecting pain receptors in the brain. They may be used in combination with anesthetic agents to modify the amount of anesthesia required during surgery. Opioids have the potential to be addictive. Therefore, they are controlled substances. More information about controlled substances is provided later in this chapter. • NSAIDs are a family of analgesic drugs that are chemically different from opioids. Aspirin may be the best known NSAID, but its use in animals is limited. Carprofen (sold under the brand name RimadylR) and meloxicam (Metacam R) are other examples of NSAIDs commonly used in laboratory animals. NSAIDs relieve pain by reducing inflammation in injured tissues. In many species, NSAIDs have the potential to injure the stomach lining, which in severe cases can cause death. Anti-inflammatory Drugs • Anti-inflammatory drugs are commonly used to reduce swelling, redness, and pain. • Steroids are a class of anti-inflammatory drugs; they suppress the immune system and, in turn, inflammation. • Steroids are commonly used in research as an immunosuppressant during organ transplantation studies. • Examples of steroids are cortisone, prednisone, and dexamethasone. Anesthetics • Anesthetics cause a loss of feeling or awareness of pain. This effect is known as anesthesia. • Anesthetics are classified as general, regional, or local, depending on how and where they act on the body. • Local anesthetics, such as lidocaine, numb a small area of the body by blocking nerve transmission. These anesthetics may be used to provide pain control to a small area, such as the margins of a cut following surgery. They may be applied as a topical cream or a liquid that may be sprayed on, or injected under the skin. • Regional anesthetics block nerve transmission in a larger area of the body, such as a limb. General anesthetics • General anesthetics affect the entire nervous system and are used to render the animal unconscious and to eliminate all sensation of pain. • A combination of drugs is usually required to achieve a state of general anesthesia. • A drug combination may reduce the length of time the animal remains under anesthesia, improve the quality of pain relief provided, and enhance the animal’s recovery from anesthesia compared to using a single drug by itself. • Injectable anesthetics: Can be given by injection into a vein. For example, propofol can be given intravenously to create a rapid loss of consciousness. Most injectable general anesthetics are controlled substances. • Inhalant anesthetics: Other types of anesthetics must be inhaled to create a state of general anesthesia. Two commonly used inhalant anesthetics are isoflurane and sevoflurane. Tranquilizers • Tranquilizers calm and sedate animals and are often used before anesthetic administration to calm the animal and induce anesthesia more smoothly. • They can also be used to reduce the amount of anesthetic needed to produce anesthesia. • Examples of common tranquilizers are acepromazine, diazepam (ValiumR), and xylazine. Antimicrobials (against life) • There are several types of drugs in this classification. • Antibiotics: Drugs that treat infections caused by bacteria. • Examples of antibiotics are enrofloxacin, doxycycline, and erythromycin. • Various antibiotics are effective against different types of bacteria. • Not all infections are caused by bacteria. • Antibiotics have no effect on infections caused by other microorganisms such as viruses, fungi, or parasites. • Antifungals: Drugs that treat infections caused by a fungus • Ringworm is an example of an infection caused by a fungus, and may be treated with the antifungal miconazole. • Antivirals: Drugs that treat infections caused by a virus. • Example: Influenza is a virus, and can be treated with an antiviral drug, such as TamifluR. Parasiticides • Parasiticides kill parasites living in an animal (such as pinworms, heartworms, or tapeworms) or on an animal (such as fleas, lice, and mites). • Ivermectin, for example, is often used against mites and lice and some internal parasites such as heartworm. • Because of the wide variety of parasites, there are different types of parasiticides. • Anthelmintics eliminate a wide variety of parasitic worms such as pinworms, heartworms, or tapeworms. Examples of anthelmintics are thiabendazole, piperazine, and ivermectin. • Insecticides kill parasitic insects, such as lice or fleas, which infest the skin and fur of an animal’s body. They are available as sprays, liquids, powders, dips, and impregnated plastic strips. Pyrethrins are examples of insecticides sometimes used on laboratory animals. • Miticides kill mites and ticks. Mites and ticks are not insects; they are arachnids, with eight legs instead of six. An example of a common miticide used to treat mange mites in rabbits is moxidectin.3 • Antiprotozoals kill protozoan parasites in the intestinal tract and in other organs of the body. Metronidazole (FlagylR) is a common drug used to kill these organisms. Vaccines • A key component of ensuring a healthy vivarium is to ensure all animals entering the facility are vaccinated against common species-specific pathogens. • As a rule, Class A dealers will provide information regarding the health status of all animals they provide. This will include their vaccine status and any other prophylactic treatment such as anthelmintics. • Vaccines are considered mandatory veterinary care under the Guide, and in many cases are required before transport. • Examples of vaccines that are commonly administered are the measles vaccine for nonhuman primates, and the distemper and rabies vaccine for both dogs and ferrets. Controlled Substances Controlled substances are drugs that are potentially addictive to humans. Controlled Substances Many tranquilizers, analgesics, and anesthetics are controlled substances as they are potentially addictive to humans. US Drug Enforcement Administration (DEA) regulates the manufacture, possession, and use of these drugs. In order to legally purchase, store, and use controlled substances, someone in the facility, usually a veterinarian or principal investigator, must register with the DEA. •This registration is required by the Controlled Substances Act. •Many states also have their own controlled substances laws that require registration at the state level as well as the Federal level. Controlled substances are classified into five groups, based on their addictiveness. These groups are known as schedules I, II, III, IV, and V. •Schedule I drugs have the highest potential for addiction. They have limited medical or veterinary uses, but they may occasionally be used in a research study. •Schedule V drugs are the least addictive. •Schedule II to V drugs have accepted medical uses; drugs used for pain relief, anesthesia, or euthanasia may be in any of these schedules. Under the controlled substances laws, the registrant has specific responsibilities for drug security and recordkeeping. Violations of these responsibilities could be punishable by fines or imprisonment. •These drugs must be stored in a securely locked cabinet or room. •A log sheet must also be kept for each bottle of a controlled substance. This documentation must be kept secure and made available to inspection by the DEA. •The license holder may authorize personnel to handle and use these drugs in research studies. These individuals must be trained in the security and recordkeeping responsibilities and must fully comply with these requirements. •Specific regulations govern the disposal of controlled substances. These drugs must be returned to the license holder for disposal, who must complete appropriate documentation when discarding controlled substances. Drug Formulations • Drugs are manufactured in a variety of forms. • Sometimes the same drug may be available in multiple forms, and the veterinarian will prescribe the appropriate form for the species and disease being treated. • Injectables: Are in a suspension or solution. • Oral Meds: Drugs given orally may be in a liquid, capsule, tablet, powder, or paste. • Topical drugs: Are applied onto a body surface, like eyes, ears, or skin, in the form of an ointment, a cream, a lotion, drops, or a spray. Drug Expiration Dates The expiration date is the date when a drug may be expected to have lost its potency. • The expiration date is printed on the bottle label and must be checked before using any drug. • If the expiration date is noted only by the month and the year (for example, May 2018), the expiration date is considered to be the last day of that month (May 31, 2018). Some types of expired drugs may be used for studies in which anesthetized animals are euthanized before they regain consciousness. • The use of expired drugs is carefully controlled and must be approved by the veterinarian and the IACUC. • The veterinarian may make a professional judgment on whether the expired drug is safe and effective for use. Expired drugs must be discarded or at least clearly marked as expired and stored separately from the drugs currently in use. Never use expired anesthetics, analgesics, tranquilizers, or euthanasia drugs. A veterinarian with the IACUC could approve the use of an expired antibiotic for an animal on a terminal study Drug Storage Conditions • Proper storage of drugs is essential to ensure safety and efficiency. An organized drug storage room makes it easy to locate a specific drug (Figure 12.1). A drug may deteriorate rapidly if it is not stored under the proper conditions. • Some drugs require refrigeration • Other drugs should be stored at room temperature. • Some drugs are sensitive to light. These should be stored in an amber glass bottle or in a lightproof container or wrapped in aluminum foil. • Storage requirements are listed on the container and in the information sheet that accompanies a drug. Drug Administration Many drugs are given orally (by mouth) or injected into the body, while others may be applied topically or inhaled. This section describes some of the more commonly used routes of drug administration. Enteral Administration Enteral means providing a drug directly into the gastrointestinal tract, either orally or rectally. • Oral administration: Drugs given orally may be mixed in feed, drinking water, or administered by mouth and swallowed. Alternatively, they may be put directly into the esophagus or stomach with a bulbed needle or stomach tube by a process called gavage. (Figure 12.2) • Rectal administration: Suppositories are a drug form that can be inserted into the rectum of larger animals. The drug is mixed with a solid that dissolves at body temperature or is water-soluble. The suppository dissolves and the drug is absorbed through the rectal lining into the bloodstream. This mode of administration is often used for animals that are vomiting. Parenteral Administration • The term “parenteral” refers to the administration of drugs by means other than through the gastrointestinal tract. • Parenteral administration techniques allow the drugs to enter the bloodstream more quickly than they would if they were swallowed and had to be absorbed from the gastrointestinal tract before reaching the blood circulation. • The drug is deposited through a needle into a body tissue or body cavity. The most common routes used for parenteral drug administration are intramuscular, intravenous, subcutaneous, and intraperitoneal injections. • The technique chosen depends on the speed with which the drug must be absorbed. The common abbreviations for each route are listed in parentheses. Inhalation • Drugs that can be delivered as a vapor or an aerosol may be administered by inhalation. • This route can be used to treat respiratory diseases because the drug is delivered directly to its site of action. • Many general anesthetics are administered by inhalation. The blood vessels in the lungs absorb the drug and the blood circulation carries the anesthetic to the brain where its primary action occurs. An anesthesia machine with a vaporizer is used to administer inhalant anesthetics. Topical Administration • Topical agents are applied directly to the body surface, such as the eyes, ears, or skin. • Topical drugs are available as creams, ointments, aqueous solutions, tinctures, powders, and sprays. • Aquatic animals, like frogs and fish, may be treated by adding the medication to the water in the tank. For example, a general anesthetic agent may be added to a water bath where the agent is absorbed through the gills (for fish) or the skin (for amphibians). Drug Treatment Records It is important for technicians to complete the required documentation when animals are administered drugs. • Facilities generally have standardized forms for animal treatment records, health records, and surgery. • Health records document observations, treatments, and procedures on the animals (Figure 12.3). • Surgery forms document the anesthesia, animal monitoring during and after surgery, and the procedure itself. • When drugs are administered, the record entry should state the drug name, the amount given, the date, and the time. The technician should sign or initial this entry. All entries should be carefully written in pen (not pencil) and be easily legible. In some facilities, errors must be addressed by correcting and initialing the mistake, not by erasing the entry. Summary • Many types of drugs are used in an animal facility. • Some drugs, such as analgesics and anesthetics, are used to alleviate pain or render the animal unconscious during experimental procedures and surgery. • Others may combat infection or parasitic infestation. • Controlled substances are drugs that have a potential for abuse, and strict rules apply to their storage, use, disposal, and recordkeeping. • Drugs may be administered orally (enteral), rectally (enteral), by injection (parenteral), or by inhalation. • Topical drugs are directly applied to the eyes, ears, or skin. • All use of drugs must be authorized by a veterinarian, and careful records must be kept. • Store drugs correctly, and use them before their expiration date. • Remember that while drugs have helpful effects, they may also alter experimental results. The decision to administer a medication to research animals generally involves consultation between the clinical veterinarian and the investigator. • Remember that the same drug may cause different effects in various species due to their unique physiological characteristics. For example, cats are very sensitive to the effects of opioids and NSAIDs. Penicillin (an antibiotic) can be fatal if given to guinea pigs, but is not harmful to most other species.