Veterinary Pharmacology and the Veterinary Technician

Veterinary Pharmacology and the Veterinary Technician

Importance of Pharmacology

  • Veterinary pharmacology is the study and use of drugs in animal health care.
  • Technicians play a crucial role in:
    • Interpreting drug orders.
    • Dispensing and administering medications.
    • Educating clients about medications.
  • Technicians need to understand:
    • Drug names.
    • Routes of administration.
    • Drug actions and expected effects.
    • Potential adverse reactions.
  • This understanding helps technicians provide better nursing care and act as "eyes and ears" for the veterinarian.

Drug Regulation and Safety

  • Drugs must be thoroughly tested for safety and effectiveness before being marketed.
  • Testing ensures safety for:
    • Animals.
    • The environment.
  • Three US government agencies regulate animal health products:
    • FDA (Food and Drug Administration).
    • EPA (Environmental Protection Agency).
    • USDA (United States Department of Agriculture).
  • The cost of research, testing, and marketing is significant, so companies must assess the need for a product to ensure profitability.
  • Before the FDA and the Pure Food and Drug Act, many harmful products were released to the public.

Historical Context of Drug Regulation

  • Pure Food and Drug Act of 1906: Established guidelines for drug safety, purity, and effectiveness.
  • Food Drug and Cosmetic Act of 1938: Required further testing to indicate safe dosing levels and proof of safety when used according to label directions.
  • 1972 Amendment: Expanded the Food, Drug, and Cosmetic Act to include over-the-counter (OTC) drug products.

FDA and USDA Regulations

  • The FDA regulates many prescription and OTC drugs but does not cover biologics (e.g., vaccines), which are regulated by the USDA.
  • The FDA's Center for Veterinary Medicine (CVM) ensures that approved veterinary products do not harm animals and that benefits outweigh potential adverse effects.
  • The FDA CVM prohibits the sale of products that cause serious harm to animals, requires accurate label information, and ensures drug manufacturers provide methods to detect drug residues in food from animals.
  • Drug manufacturers must provide appropriate withdrawal times for products used in food-producing animals to prevent drug traces in products for human consumption.

Drug Residue Prevention

  • Dairy farms maintain clean environments to prevent bacterial contamination and drug residues in milk.
  • Milk is tested for bacterial contamination and drug residues; contaminated milk must be discarded.
  • Sick cows are removed from the milk line to prevent herd contamination and milk contamination.
  • Cows treated with antibiotics are removed from the milk line until they complete treatment and pass withdrawal times.

Technician Responsibilities

  • Technicians may be responsible for:
    • Filling prescriptions.
    • Administering medications.
    • Educating clients on medication administration.
    • Calculating drug doses for anesthesia or fluid rates.
  • Technicians must understand their roles, responsibilities, limitations, and boundaries.
  • Technicians may not prescribe medications or create treatment regimens but can administer drugs under a veterinarian's order.
  • The veterinarian communicates prescription details (medication, dosage, frequency), followed by a written plan in the patient chart.

Medication Administration and Documentation

  • Technicians must understand how to properly administer medications via appropriate routes and precautions.
  • Technicians may be responsible for labeling medications with legal information and clear administration instructions.
  • Precise instructions are crucial to avoid misinterpretation (e.g., "twice a day" should be specified).
  • All dispensed or administered medications must be documented in the patient's medical record, including:
    • Medication name and strength.
    • Amount dispensed or administered.
    • Time and date of administration.
    • Person administering the medication.
    • Patient observations (e.g., alertness, responsiveness).

Importance of Understanding Drug Actions

  • Technicians need awareness of how medications work and affect patients to recognize adverse reactions (e.g., allergic reactions).
  • Technicians should understand:
    • Indications (reasons for using drugs).
    • Contraindications (reasons for not using drugs).
  • Pharmacotherapeutics is the field studying drug use in disease treatment; understanding this helps technicians provide better care.
  • Pharmacokinetics refers to what happens to drugs once they enter a patient like how it is absorbed, used, and eliminated to prevent accumulation and toxicity.

Adverse Reactions and Client Communication

  • Technicians need to be aware of signs and symptoms of adverse reactions and toxic levels of medications.
  • During history taking, clients may reveal home remedies they are using, which technicians should inform the doctor about to prevent interactions.

Categories of Medications

  • Drugs and medications fall into four categories:
    • Over-the-counter (OTC) drugs.
    • Prescription drugs.
    • Extra-label drugs.
    • Controlled substances.

Over-the-Counter (OTC) Drugs

  • OTC drugs can be sold without a veterinarian's prescription.
  • They typically have low potential for toxicity or abuse.
  • Some OTC drugs were originally prescription medications but were found safe when used as directed (e.g., allergy medications like Zyrtec and Claritin).
  • OTC medications usually involve easy administration routes (topical, oral) and have low risk of toxicity or abuse.
  • Examples of OTC drugs used in veterinary medicine include:
    • Aspirin.
    • Diphenhydramine (Benadryl).
    • Kaolin-pectin.

Prescription Drugs

  • Prescription drugs are regulated by the FDA and require veterinary supervision due to potential adverse reactions, toxicities, or difficult administration routes.
  • They may be dispensed to clients or used in-hospital for patient treatment.
  • Veterinarians consider the client's ability to properly administer the medication before dispensing it.
  • A veterinarian-client-patient relationship (VCPR) must be established before a prescription can be written.
  • The veterinarian must examine the patient, gather diagnostic information, reach a diagnosis, and create a treatment regimen.
  • Prescriptions should not be given to a client that describes symptoms for a pet that the veterinarian has never examined.

Prescription Drug Labels

  • Every drug label includes:
    • Product name (brand name).
    • Chemical name of the drug (generic name).
    • Statement of drug strength (e.g., 60 grams total, 12 grams phenobutasone).
    • Statement indicating the product is for veterinary use only (e.g., equine use).
    • Lot number and expiration date.
    • Dosage amount and route of administration.
    • Prescription drug statement (legend): "Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian."

Examples of Prescription Labels

  • Example 1: Equivar Butepaste
    • Product name: Equivar Butepaste
    • Chemical name: Phenobutasone
    • Strength: 60 grams (12 grams phenobutasone)
    • Indication: Equine use only
    • Label contains 12 marks or divisions, with each division indicating 1 gram of butepaste.
  • Example 2: Marbofloxacin
    • Product name: Marbifloxacin
    • Generic Name: Marbofloxacin
    • Strength: 25 milligram tablet
    • Legend statement: Can only be used or dispensed by or on the order of a licensed veterinarian.
    • Contains specific information that restricts or prohibits extra label use in food producing animals.

Extra-Label Drug Use

  • Extra-label use refers to using a drug in veterinary patients when the approved label is only for human use or for a condition not on the FDA-approved label.
  • For example, using human-labeled diphenhydramine (Benadryl) in animals.
  • A VCPR must exist, and the veterinarian accepts responsibility for the outcome.
  • Extra-label use is strongly discouraged by some organizations and regulations.
  • The decision to use a product in a manner not indicated on the label is at the discretion of the veterinarian.

Controlled Substances

  • Controlled substances are highly monitored and regulated drugs with a high potential for human misuse or abuse.
  • The DEA (Drug Enforcement Agency) enforces laws under the Controlled Substances Act of 1970 to ensure proper use and storage.
  • These drugs are classified into five schedules (classes) according to their potential for abuse.
  • Schedule I drugs (e.g., heroin, LSD, marijuana) have a high potential for abuse without recognized medical use.
  • Schedule V drugs (e.g., codeine cough syrups, buprenorphine) have a low potential for abuse.

Controlled Substance Handling

  • Detailed records must be kept on administered or dispensed controlled substances.
  • Veterinarians prescribing controlled substances must register annually with the DEA and list their DEA registration number on prescriptions and supply orders.
  • Controlled substances must be stored in a securely locked cabinet or safe.
  • A controlled substance log must reflect orders, receipts, use, discards, and thefts.
  • These records must be kept for at least two years and may be reviewed during DEA inspections.
  • Controlled substance labels include the product name, chemical name, dosage information, restrictive statement, and schedule number (e.g., Schedule IV).
  • Schedule IV drugs (e.g., phenobarbital, diazepam/Valium) have a low potential for abuse and accepted medical uses.

Medication Handling and Disposal

  • Technicians and veterinary assistants must understand special handling protocols for medications.
  • Verify disposal protocols before discarding any medication; consult the product's Material Safety Data Sheet (MSDS).
  • Contact a supervisor or the drug manufacturer if unsure about disposal information.
  • OSHA, EPA, and FDA standards apply to the disposal of chemicals, drugs, and medications.
  • Animal waste (e.g., from chemotherapy patients) may be considered toxic and require special disposal.
  • Expired controlled substances are handled by the DPS or DEA, and destruction must be documented in the controlled substance log.
  • Biohazard containers may be required for disposal of antibiotics and chemotherapeutic agents.
  • Proper disposal protects oneself, the veterinarian, and the environment.

Key Takeaways

  • Research and regulating agencies involved in the veterinary pharmacy.
  • Roles and responsibilities of the veterinary technician in the veterinary hospital pharmacy.
  • Components of the veterinarian-client-patient relationship.
  • Basic categories of medications: OTC, prescription, extra-label, and controlled substances.