Cover Page

CONTENTS

Contributors

Preface

Section 1: Principles of Pharmacology

Chapter 1: Veterinary Pharmacology: An Introduction to the Discipline

History of Pharmacology

Veterinary Pharmacology

Regulations

What Is Veterinary Pharmacology?

Chapter 2: Absorption, Distribution, Metabolism, and Elimination

An Overview of Drug Disposition

Drug Passage Across Membranes

Absorption

Distribution

Renal Elimination

Hepatic Biotransformation and Biliary Excretion

Conclusion

Chapter 3: Pharmacokinetics

A Primer on the Language of Pharmacokinetics

The Concept of Half-Life

One-Compartment Open Model

Two-Compartment Models

Multicompartmental Models

Noncompartmental Models

Nonlinear Models

Summary of Modeling Approaches

Dosage Regimens

Interspecies Extrapolations

Conclusion

Chapter 4: Mechanisms of Drug Action and Pharmacokinetics/Pharmacodynamics Integration in Dosage Regimen Optimization for Veterinary Medicine

Introduction

Types of Drug Targets

Drug Receptor and Ligand as Agonist or Antagonist

Drug Affinity, Efficacy, and Potency

Drug Specificity and Selectivity

Chemical Forces and Drug Binding

Macromolecular Nature of Drug Receptors

Receptor Types and Subtypes

Down- and Up-Regulation

An Overview on the Determination of an Effective and Safe Dosage Regimen

Designs for Dose Titration and the Determination of an Effective Dose

The Difference Between Dose Titration and the PK/PD Modeling Approach in Determining a Dose

Building PK/PD Models

Selection of the Dose and Dosage Regimen

Population PK/PD

Limits of the PK/PD Modeling Approach for a Dose Determination: Clinical Response Versus Surrogate

Conclusion

Section 2: Drugs Acting on the Autonomic Nervous System

Chapter 5: Introduction to Neurohumoral Transmission and the Autonomic Nervous System

Organization of the Autonomic Nervous System

General Concepts of Autonomic Function

Neurohumoral Transmission

Adrenergic Neurohumoral Transmission

Cholinergic Neurotransmission

Autonomic Receptor Sites on Nerve Terminals

Putative Neurohumoral Substances

Nitric Oxide

G Proteins and Cyclic Nucleotides

Autonomic Drugs

Chapter 6: Adrenergic Agonists and Antagonists

Adrenergic (Sympathomimetic) Drugs

Catecholamines

Noncatecholamines

α2-Selective Agonists

β2-Selective Bronchodilators

Antiadrenergic Drugs

Chapter 7: Cholinergic Pharmacology: Autonomic Drugs

Parasympathomimetic Agents

Direct-Acting Parasympathomimetic Agents

Cholinesterase Inhibitors

Parasympatholytic Agents

Autonomic Ganglionic Blocking Drugs

Section 3: Anesthetics and Analgesics

Chapter 8: Introduction to Drugs Acting on the Central Nervous System and Principles of Anesthesiology

Introduction to CNS Drugs

Principles of Anesthesiology

Chapter 9: Neuromuscular Blocking Agents

Development

The Nicotinic Receptor and Structure-Activity Relationships

Impulse Transmission at the Somatic Neuromuscular Junction

Postjunctional Mechanisms of Neuromuscular Blockade

Pharmacologic Effects of Neuromuscular Blocking Agents

Interactions

Clinical Use

Chapter 10: Inhalation Anesthetics

Physiochemical Characteristics

Properties Determining Methods of Administration

Properties Influencing Drug Kinetics: Solubility

Pharmacokinetics: Uptake and Elimination of Inhalation Anesthetics

Pharmacodynamics: Actions and Toxicity of the Inhalation Anesthetics

Trace Concentrations of Inhalation Anesthetics: Occupational Exposure

Chapter 11: Injectable Anesthetic Agents

Indications for Injectable Anesthesia

Disadvantages of Injectable Anesthesia

Properties of an Ideal Injectable Anesthetic Drug

Barbiturates

Propofol

Dissociatives

Etomidate

Guaifenesin

Neurosteroids

Miscellaneous Intravenous Anesthetics

Chapter 12: Opioid Analgesic Drugs

Introduction

Background on Opioids

Opioid Pharmacodynamics

Opioid Pharmacokinetics

Clinical Pharmacology

Opioid Agonists

Partial and Mixed Receptor Opioids

Opioid Antagonists

Other Central Analgesic Drugs

Other Routes of Administration

The Use of Opioids in Nonmammalian Vertebrates

Chapter 13: Sedative Agents: Tranquilizers, Alpha-2 Agonists, and Related Agents

Phenothiazine Derivatives

Phenothiazines Used in Veterinary Practice

α2-adrenergic Agonists

Specific Alpha-2 Agonists

α2-adrenergic Antagonists

Benzodiazepine Derivatives

Benzodiazepine Antagonists

Butyrophenone Derivatives

Chapter 14: Local Anesthetics

Mechanisms

Structure and Chemistry

Metabolism

Formulation

Toxicity of Local Anesthetics

Stability

Drug Interactions and Disease

Regulatory Issues

Individual Drugs

Topical Use: Skin and Mucous Membranes

Topical Use: Opthamology

Using Local Anesthetics

Future Outlook

Chapter 15: Euthanizing Agents

Inhaled Agents

Injected Agents

Other Injectable Anesthetics and Sedatives

Ingested Agents

Immersion Agents

Miscellaneous Considerations

Section 4: Autacoids and Antiinflammatory Drugs

Chapter 16: Histamine, Serotonin, and Their Antagonists

Histamine

Antihistamines

Serotonin

Chapter 17: Peptides: Angiotensin and Kinins

Angiotensin

Kinins

Other Peptides

Chapter 18: Prostaglandins, Related Factors, and Cytokines

History

Chemistry and Terminology of Prostaglandins

Biosynthesis of Eicosanoids

Inhibition of Biosynthesis of Eicosanoids

Physiologic-Pharmacologic Aspects of Eicosanoids

Platelet-Activating Factor

Cytokines

Chapter 19: Analgesic, Antiinflammatory, Antipyretic Drugs

The Role of Eicosanoids in Inflammation and Mechanisms of Action of NSAIDs

Isoforms of Cyclooxygenase: Characteristics, Locations, and Roles

History of NSAIDs

The Veterinary NSAID Market

Classification of NSAIDs and Physicochemical Properties

Pharmacology of NSAIDs

NSAID Pharmacokinetics

NSAID Pharmacodynamics

Novel NSAID Classes

Additional Mechanisms of Action of NSAIDs

Toxicity of NSAIDs

Therapeutic Uses of NSAIDs

Chapter 20: Anticonvulsant Drugs

Introduction

Phenobarbital

Primidone

Phenytoin

Valproic Acid (Valproate)

Diazepam

Clonazepam

Clorazepate

Felbamate

Gabapentin

Levetiracetam

Zonisamide

Potassium Bromide

Treatment of Status Epilepticus

Chapter 21: Drugs Affecting Animal Behavior

Introduction

Pharmacokinetic Issues for Behavior Drugs

Neurotransmitters

Major Drug Classes

Drug Combinations

Treatment Success

Summary

Section 5: Drugs Acting on the Cardiovascular System

Chapter 22: Digitalis, Positive Inotropes, and Vasodilators

Basic Aspects of Cardiac Function

Positive Inotropes and Inodilators

Angiotensin-Converting Enzyme Inhibitors

Vasodilator Drugs

Ancillary Therapy in Congestive Heart Failure

New/Experimental Heart Failure Drugs

Chapter 23: Antiarrhythmic Agents

Rhythmicity of the Heart

Antiarrhythmic Drugs

Class I Agents

Class II Agents

Class III Agents

Class IV Agents

Section 6: Drugs Affecting Renal Function and Fluid-Electrolyte Balance

Chapter 24: Principles of Acid-Base Balance: Fluid and Electrolyte Therapy

Composition and Distribution of Body Fluids

Water, Sodium, and Chloride

Potassium

Principles of Acid-Base Metabolism

Disorders of Acid-Base Metabolism

Practical Aspects of Fluid Therapy

Products for Fluid Therapy

Special Topics

Chapter 25: Diuretics

Renal Physiology

Principles of Diuretic Use

Inhibitors of Carbonic Anhydrase

Osmotic Diuretics

Inhibitors of Na+-K+-2Cl Symport (Loop, or High-Ceiling, Diuretics)

Inhibitors of Na+-Cl Symport (Thiazide and Thiazidelike Diuretics)

Inhibitors of Renal Epithelial Sodium Channels (K+-Sparing Diuretics)

Antagonists of Mineralocorticoid Receptors (Aldosterone Antagonists and K+-Sparing Diuretics)

New and Experimental Agents

Section 7: Drugs Acting on Blood and Blood Elements

Chapter 26: Hemostatic and Anticoagulant Drugs

Hemostasis

Hemostatic Drugs

Anticoagulants

Fibrinolytic Agents

Antiplatelet Drugs

Section 8: Endocrine Pharmacology

Chapter 27: Hypothalamic and Pituitary Hormones

Introduction

Anterior Pituitary and Associated Regulatory Hormones

Corticotropin and Related Peptides

Melatonin

Glycoprotein Hormones and Associated Releasing Hormones

Posterior Pituitary Hormones

Antidiuretic Hormone (ADH)

Oxytocin

Chapter 28: Hormones Affecting Reproduction

Introduction

Estrous Cycle

GnRH, Gonadorelin, and Gonadotropins

Estrogens and Progesterone

Specific Reproductive Conditions

Androgens

Chapter 29: Thyroid Hormones and Antithyroid Drugs

Introduction

Thyroid Physiology

Extrathyroidal Factors Altering Thyroid Hormone Metabolism

Mechanisms of Thyroid Hormone Action

Thyroid Hormone Preparations

Antithyroid Drugs

Thyroid Imaging

Chapter 30: Glucocorticoids, Mineralocorticoids, and Adrenolytic Drugs

Glucocorticoids

Mineralocorticoids

Adrenolytic Drugs and Steroid Synthesis Inhibitors

Chapter 31: Drugs Influencing Glucose Metabolism

Insulin

Oral Hypoglycemic Agents

Glucagon

Glucagon-like Peptide 1 Receptor Agonist

Somatostatin

Miscellaneous

Section 9: Chemotherapy of Microbial Diseases

Chapter 32: Antiseptics and Disinfectants

Cleansers

Antiseptics and Disinfectants

Factors Affecting Efficacy of Antiseptics

Microbial Resistance to Disinfectants and Antiseptics

Antiseptic Usage in Veterinary Medicine

Disinfectant Usage in Veterinary Medicine

Chapter 33: Sulfonamides and Potentiated Sulfonamides

Pharmacology of Sulfonamides

Pharmacokinetics of Sulfonamides

Adverse Effects Caused by Sulfonamides

Sulfonamides in Veterinary Medicine

Potentiated Sulfonamides

Residues in Food Animals

Chapter 34: β-Lactam Antibiotics: Penicillins, Cephalosporins, and Related Drugs

Mechanism of Action of β-Lactam Antibiotics

Microbial Resistance to β-Lactam Antibiotics

Penicillins

Cephalosporins

Carbapenems (Penems)

Chapter 35: Tetracycline Antibiotics

General Pharmacology of Tetracyclines

Commonly Used Tetracyclines

Other Non-Antimicrobial Uses of Tetracyclines

Chapter 36: Aminoglycoside Antibiotics

Pharmacology of Aminoglycosides

Pharmacokinetics of Aminoglycosides

Aminoglycoside Toxicity

Examples of Drugs

Chapter 37: Chloramphenicol and Derivatives, Macrolides, Lincosamides, and Miscellaneous Antimicrobials

Chloramphenicol

Chloramphenicol Derivatives

Macrolide Antibiotics

Lincosamides

Miscellaneous Antibiotics

Chapter 38: Fluoroquinolone Antimicrobial Drugs

Chemical Features

Mechanism of Action

Antibacterial Spectrum

Resistance

Pharmacokinetics

Pharmacodynamics (PK-PD)

Dose Guidelines

Clinical Use

Safety

Drug Interactions

Formulations Available

New Developments

Chapter 39: Antifungal and Antiviral Drugs

Antifungal Drugs

Griseofulvin

Amphotericin B

Azole Antifungal Drugs

Other Antifungal Agents

Topical Antifungal Agents

Antiviral Therapy

Idoxuridine and Trifluridine

Cytarabine and Vidarabine

Ribavirin

Acyclovir, Penciclovir, and Related Prodrugs (Valacyclovir and Famciclovir)

Zidovudine

Foscarnet

Amantadine and Rimantadine

Interferon

L-lysine

PMEA

Section 10: Chemotherapy of Parasitic Diseases

Chapter 40: Antinematodal Drugs

Benzimidazoles and Probenzimidazoles

Factors Affecting the Disposition Kinetics and Efficacy of Benzimidazole Anthelmintics

Imidazothiazoles

Tetrahydropyrimidines

Organophosphate Compounds

Heterocyclic Compounds

Heartworm Adulticides: Organic Arsenicals

Resistance to Anthelmintic Compounds: Molecular Basis

Miscellaneous and Novel Anthelmintic Drugs

Concluding Remarks

Chapter 41: Anticestodal and Antitrematodal Drugs

Anticestodal Drugs

Introduction

Bunamidine

Niclosamide

Praziquantel

Epsiprantel

Antitrematodal Drugs

Introduction

Nitrophenolic Compounds

Salicylanilides

Benzenesulfonamides

Benzimidazoles

Phenoxyalkanes

Chapter 42: Macrocyclic Lactones: Endectocide Compounds

General Pharmacology: Avermectins and Milbemycins

Mechanism of Action: Ecto-Endoparasiticidal Activity

Pharmacokinetics

Pharmacokinetic-Pharmacodynamic Relationship

Therapeutic Uses: Animal Species-Specific Considerations

Resistance

Available Pharmaceutical Preparations

Drug and Host-Related Factors Affecting Pharmacokinetics and Efficacy in Ruminants

Tissue Residues and Withdrawal Times

Safety and Toxicity

Ecotoxicological Impact

Concluding Remarks

Chapter 43: Antiprotozoan Drugs

Nitroimidazoles

Pentavalent Antimonials

Arsenicals

Benzimidazoles

Aminoglycosides

Nitrofurans

Tetracyclines

Hydroxyquinolones and Naphthoquinones

Pyridinols

Guanidine Derivatives

Thiamine Analogues

Nitrobenzamides

Nicarbazin

Alkaloids

Polyether Ionophores

Triazine Derivatives

Sulfonamides

Dihydrofolate Reductase/Thymidylate Synthase Inhibitors

Lincosamides

Azalides

4-Aminoquinolines

Diamidine Derivatives

Nitrothiazole Derivatives

Chapter 44: Ectoparasiticides

Introduction

Pharmaceutics of Topical Formulations

Transdermal Delivery

Routes of Dermal Absorption

Mechanisms of Action

Resistance to Ectoparasiticides

Fipronil

Neonicotinoids

Macrocyclic Lactones

Pyrethrins and Synthetic Pyrethroids

Organophosphates

Carbamates

d-Limonene and Linalool

Amitraz

Insect Growth Regulators (IGRs)

Synergists and Repellents

Ectoparasiticide Approval and Registration in the U.S.

Section 11: Specialty Areas of Pharmacology

Chapter 45: Chemotherapy of Neoplastic Diseases

Treatment Perspectives

Cancer Biology

Drugs

Chapter 46: Immunosuppressive Drugs and Cyclosporine

Glucocorticoids

Cyclosporine

Tacrolimus, Pimecrolimus, and Sirolimus

Cyclophosphamide (Cytoxan®)

Chlorambucil

Thiopurines (Azathioprine)

Mycophenolate

Danazol

Gold Therapy (Chrysotherapy)

Dapsone

Chapter 47: Drugs Affecting Gastrointestinal Function

Antiemetic Drugs

Gastrointestinal Prokinetic Drugs

Drugs for Treatment of GI Ulcers in Animals

Drugs for Treatment of Diarrhea

Drugs for Treatment of Inflammatory Intestinal Diseases

Laxatives and Cathartics

Chapter 48: Dermatopharmacology: Drugs Acting Locally on the Skin

Anatomy and Histology

Biochemistry

Principles of Percutaneous Absorption: Skin Permeability

Topical Vehicles

Classification of Dermatologic Vehicles

Classes of Medicated Applications

Dermatotherapy: Atopic Dermatitis

Chapter 49: Drugs that Affect the Respiratory System

Antitussive Drugs

Bronchodilator Drugs (Beta-Adrenergic Receptor Agonists)

Cromolyn (Sodium Cromoglycate) (INTAL®)

Methylxanthines (Xanthines)

Anticholinergic Drugs

Glucocorticoids

Nonsteroidal Antiinflammatory Drugs (NSAIDs)

Leukotriene Inhibitors

Expectorants and Mucolytic Drugs

Decongestants

Respiratory Stimulants

Chapter 50: Pharmacogenomics

Basic Genetic Concepts

Pharmacogenetics

Chapter 51: Therapeutic Drug Monitoring

Therapeutic Drug Monitoring: Considerations

Phenobarbital

Bromide

Cyclosporine

Aminoglycosides

Digoxin

Chapter 52: Considerations for Treating Minor Food-Producing Animals with Veterinary Pharmaceuticals

The Use of Veterinary Pharmaceuticals in Minor Food-Producing Animals: Special Considerations and Challenges

The Approval Process for Veterinary Pharmaceuticals for Use in Minor Food-Producing Animals

Legislation and Policies Supporting the Use of Veterinary Pharmaceuticals in Minor Food-Producing Animals

Programs Supporting the Use of Veterinary Pharmaceuticals in Minor Food-Producing Animals

Methods for Estimating Withdrawal Intervals for Veterinary Pharmaceuticals Administered to Minor Food-Producing Animals in an Extralabel Manner

Summary

Chapter 53: Zoological Pharmacology

Introduction

Species Groups

Allometry in Zoo Medicine

Section 12: Regulatory Considerations

Chapter 54: Legal Control of Veterinary Drugs

Legislative Milestones in the Development of Laws Pertaining to the Regulation of Animal Drugs

Drug Compendia

Chapter 55: Drug Approval Process

Introduction

History of the FDA and Its Relationship to Veterinary Medicine

Challenges in Veterinary Drug Evaluation

Regulatory Basis of Veterinary Drug Evaluation

The Office of Minor Use and Minor Species Animal Drug Development

International Harmonization

Adverse Drug Experience Reports

Leveraging with the FDA

The Use and Application of Pharmacokinetic Information

Chapter 56: Veterinary Pharmacy

Introduction

Regulatory Requirements for Use of Drugs in Animal Patients

Regulatory Discretion for Extralabel Use

Need for Legal Extralabel Use—AMDUCA

Classification of Drugs

Current Status of Compounded Veterinary Drugs

Potential Problems from Compounded Drugs

Unapproved Drugs Available by Importation

Prescribing Controlled Substances

Dispensing Medications Intended to Go Home with a Patient

Prescription Writing

Chapter 57: Regulation of Drug and Medication Use in Performance Animals

Drug and Medication Rules

The Drug Testing Process

Factors Affecting Withdrawal Times

Thresholds, Reporting Levels, and Cutoffs

Summary

Chapter 58: Adverse Drug Reactions

Method

Strengths of ADE Reporting Systems

Limitations of ADE Reporting Systems

Chapter 59: Dosage Forms and Veterinary Feed Directives

Pharmacokinetic Considerations and Controlled-Drug Delivery

Palatability and Ease of Drug Administration

Veterinary Feed Additives

Site-Directed Therapy

Chapter 60: USP’s Role in Veterinary Pharmacology and Evidence-Based Information

USP and Its Compendia

USP Evidence-Based Pharmacotherapy

Chapter 61: Chemical Residues in Tissues of Food Animals

The Concern over Residues in Food

Regulation of Drug Residues in Animals

Pharmacokinetics and Residues

Drugs Prohibited from Extralabel Use

Residue Prevention

Index

Title Page

CONTRIBUTORS

H. Richard Adams, DVM, PhD

Diplomate ACVECC (Hon)

Dean Emeritus

College of Veterinary Medicine, University of Missouri

Carl B. King Dean of Veterinary Medicine

College of Veterinary Medicine and Biomedical Sciences

Texas A&M University

College Station, Texas 77843-4461

Luis I. Alvarez, Med Vet, PhD

Assistant Professor

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

Argentina

Ronald E. Baynes, DVM, PhD

Associate Professor

Department of Population Health and Pathobiology

Center for Chemical Toxicology Research and Pharmacokinetics

North Carolina State University

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Melanie Berson, DVM

Director

Division of Therapeutic Drugs for NonFood Animals

Office of New Animal Drug Evaluation

Food and Drug Administration

Center for Veterinary Medicine

7500 Standish Place

FDA/CVM/HFV-110

Rockville, MD 20855

Margarita A. Brown, DVM, MS

Safety Review Coordinator

Office of Surveillance and Compliance

Center for Veterinary Medicine

U.S. Food and Drug Administration

7519 Standish Place

Rockville, MD 20855

Patrick Burns, BVSc, MACVSc

DACVA

College of Veterinary Medicine

The Ohio State University

601 Vernon L. Tharp Street

Columbus, OH 43210

Cynthia A. Cole, DVM, PhD

DACVCP

IDEXX Pharmaceuticals, Inc.

7009 Albert Pick Road

Greensboro, NC 27409

Gordon L. Coppoc, DVM, PhD

Professor and Head

Department of Basic Medical Sciences

School of Veterinary Medicine

Purdue University

625 Harrison Street

West Lafayette, IN 47907-2026

Arthur L. Craigmill, PhD

DABT

Environmental Toxicology Extension

University of California

One Shields Avenue

Davis, CA 95616

Gigi Davidson, RPh

Director of Clinical Pharmacy Services

VTH Pharmacy

North Carolina State University

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Jennifer L. Davis, DVM, PhD

Diplomate ACVIM, Diplomate ACVCP

Department of Clinical Sciences

North Carolina State University

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Ian F. DeVeau, PhD

Director

Veterinary and Radiopharmaceuticals Group

United States Pharmacopeia

Department of Standards Dev

12601 Twinbrook Parkway

Rockville, MD 20852-1790

Levent Dirikolu

Physiology and Pharmacology

College of Veterinary Medicine

501 DW Brooks Drive

Athens, GA 30602

Bernadette Dunham, DVM, PhD

Director

Center for Veterinary Medicine

U.S. Food and Drug Administration

MPN-IV, Room 181, HFV-1

7519 Standish Place

Rockville, MD 20855

Duncan Ferguson, VMD, PhD

Diplomate ACVCP, Diplomate ACVIM

Veterinary Biosciences

The University of Illinois College of Veterinary Medicine Urbana, IL 61801

John Gadsby, PhD

Professor

Department of Molecular Biomedical Sciences

College of Veterinary Medicine

North Carolina State University

4700 Hillsborough Street

Raleigh, NC 27606

Jody L. Gookin, DVM, PhD

Diplomate ACVIM

Assistant Professor

Department of Clinical Sciences

College of Veterinary Medicine

North Carolina State University

4700 Hillsborough Street

Raleigh, NC 27606

Joan Gotthardt, DVM

Director

Division of Therapeutic Drugs for Food Animals

Office of New Animal Drug Evaluation

Division of Therapeutic Drugs for Food Animals

FDA Center for Veterinary Medicine

7500 Standish Place

FDA/CVM/HFV-110

Rockville, MD 20855

Victoria Hampshire, VMD

Senior Regulatory Veterinarian and Reviewer

CDRH/ODE/DCD/PVDB

9200 Corporate Boulevard

HFZ-450

Rockville, MD 20850

Mark C. Heit, DVM, PhD

DACVCP

Senior Director, Research and Development

Velcera Inc.

777 Township Line Road

Yardely, PA 19067

Margarethe Hoenig, DVM

Professor

Physiology and Pharmacology

College of Veterinary Medicine

501 DW Brooks Drive

Athens, GA 30602

Laura Hungerford, DVM, MPH, PhD

Senior Advisor for Science Policy

Center for Veterinary Medicine

Office of New Animal Drug Evaluation

U.S. Food and Drug Administration

7500 Standish Place

FDA/CVM/HFV-100

Rockville, MD 20855

Robert P. Hunter, MS, PhD

Elanco Animal Health

2001 West Main Street

P.O. Box 708

Greenfield, IN 46140

Fernanda A. Imperiale, Vet, PhD

Research Fellow

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Deborah T. Kochevar, DVM, PhD

DACVCP

Henry and Lois Foster Professor

Dean

Cummings School of Veterinary Medicine

Tufts University

200 Westboro Road

North Grafton, MA 01536

Butch KuKanich, DVM, PhD

Diplomate ACVCP

Department of Anatomy and Physiology

College of Veterinary Medicine

Kansas State University

228 Coles Hall

Manhattan, KS 66506-5802

Cory Langston, DVM, PhD

Diplomate ACVCP

Professor

College of Veterinary Medicine

Box 6100

Spring Street

Mississippi State University

Starkville, MS 39762-6100

Carlos E. Lanusse, Med Vet Dr Cs Vet, PhD

Diplomate ECVPT

Professor

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Peter Lees, PhD, DSc

Royal Veterinary College

Hawkshead Campus

London University

North Mymms

Hatfield, Hertfordshire, AL97TA

United Kingdom

Adrian L. Lifschitz, Vet, PhD

Lecturer

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Marilyn Martinez, PhD

Senior Research Scientist

Center for Veterinary Medicine

U.S. Food and Drug Administration

7500 Standish Place

Rockville, Maryland 20855

Katrina L. Mealey, DVM, PhD

DACVIM, DACVCP

Department Veterinary Clinical Sciences

College of Veterinary Medicine

Washington State University

ABDF 1020

Pullman, WA 99164-6610

Matthew W. Miller, DVM, MS

Diplomate ACVIM (Cardiology)

Professor of Cardiology

Charter Fellow

Michael E. DeBakey Institute

Department of Small Animal Clinical Sciences

College of Veterinary Medicine and Biomedical Sciences

Texas A&M University

College Station, Texas 77843-4461

Maria L. Mottier, Vet, PhD

Research Fellow

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Margaret Oeller, DVM

Office of Minor Use and Minor Species Animal Drug Development

Center for Veterinary Medicine

U.S. Food and Drug Administration

7500 Standish Place

Rockville, MD 20855

Luisito S. Pablo, DVM, MS

Diplomate ACVA

Department of Large Animal Clinical Sciences

College of Veterinary Medicine

University of Florida

PO Box 100136

Gainesville, FL 32610

Mark G. Papich, DVM

Diplomate ACVCP

Professor

North Carolina State University

Department of Molecular Biomedical Sciences

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Peter J. Pascoe, BVSc

DACVA, DECVA

Professor

Department of Surgical and Radiological Sciences

School of Veterinary Medicine

University of California

Davis, CA 95616-8745

Lysa P. Posner, DVM

Diplomate ACVA

Associate Professor

Anesthesiology Section

Department of Molecular Biomedical Sciences

North Carolina State University

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Srujana Rayalam, BVSc, MVSc

The University of Georgia

College of Veterinary Medicine

Athens, GA 30602

Doodipala Samba Reddy, R.Ph., Ph.D.

Associate Professor

Dept of Neuroscience and Experimental Therapeutics College of Medicine

Texas A&M Health Science Center

228 Reynolds Medical Building

College Station, Texas 77843

Jim E. Riviere, DVM, PhD DSc(hon)

Director and Distinguished Professor

Center for Chemical Toxicology Research and Pharmacokinetics

Department of Population Health and Pathobiology

North Carolina State University

College of Veterinary Medicine

4700 Hillsborough Street

Raleigh, NC 27606

Juan M. Sallovitz, Med Vet, PhD

Research Fellow

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Sergio F. Sanchez Bruni, Med Vet, PhD

Associate Professor

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Stefan Schuber, PhD

Director

Scientific Reports

United States Pharmacopeia

12601 Twinbrook Parkway

Rockville, MD 20852-1790

Maya Scott, DVM, PhD

4466 TAMU

Veterinary Physiology and Pharmacology

Texas A & M University

College Station, TX 77843-4466

Barbara L. Sherman, MS, PhD, DVM

DACVB

Clinical Associate Professor

Department of Clinical Sciences

College of Veterinary Medicine

North Carolina State University

4700 Hillsborough Street

Raleigh, NC 27606-1496

Geof W. Smith, DVM, PhD

Assistant Professor

Department of Population Health and Pathobiology

College of Veterinary Medicine

North Carolina State University

4700 Hillsborough Street

Raleigh, NC 27606

Eugene P. Steffey, MVD, PhD

Professor

Department of Surgical & Radiological Sciences

School of Veterinary Medicine

University of California

2112 Tupper Hall

Davis, California 95616

Stephen F. Sundlof, DVM, PhD

DABVT

Director

Center for Food Safety and Applied Nutrition

U. S. Food and Drug Administration

5100 Paint Branch Parkway

College Park, MD 20740

Lisa A. Tell, DVM

Professor

Diplomate ABVP, Diplomate ACZM

Food Animal Residue Avoidance Databank and National Research Project 7

Department of Medicine and Epidemiology

School of Veterinary Medicine

University of California

One Shields Avenue

Davis, CA 95616

Pierre-Louis Toutain, DVM, Dr Sci

Diplomate ECVPT

UMR 181 Physiopathologie et Toxicologie Experimentales

INRA/ENVT

Ecole Nationale Veterinaire de Toulouse

23 chemin des Capelles—BP 87614 31076 TOULOUSE cedex 03 FRANCE

Guillermo L. Virkel, Med Vet, PhD

Lecturer

Laboratorio de Farmacologis

Departamento de Fisiopatologia

Facultad de Ciencias Veterinarias

Universidad Nacional del Centro

Campus Universitario

(7000) Tandil

Argentina

Alistair Webb, BVSc, PhD

FRCVS, MRCA, DVA, Diplomate ACVA

Department Physiological Sciences

College of Veterinary Medicine

University of Florida

PO Box 100144

Gainesville, FL 32610-0144

Keith Zientek, PhD

Senior Scientist

Bioanalytical Systems, Inc.

3138 NE Rivergate, Bldg. 301C

McMinnville, OR 97128

PREFACE

Welcome to the ninth edition of Veterinary Pharmacology and Therapeutics, the first edition of which was authored some 6 decades ago by Dr. L. Meyer Jones, a father of American veterinary pharmacology. As with previous editions, this book remains dedicated to veterinary medical students enrolled in professional schools and colleges of veterinary medicine. However, this book also has a broader audience in that veterinary medicine interns and residents, graduate students in comparative biomedical sciences, laboratory animal specialists, and researchers using animals have adopted this as the standard source for information available on comparative pharmacology.

The present edition is both an outgrowth of, and extension to, the eighth edition edited by H. Richard Adams. The major changes are focused on integrating topics covered in the traditional drug-specific chapters to several new chapters covering their applications in areas such as minor species or racing animals. The chapters on treatment of clinical problems are also greatly expanded to integrate the basic concepts discussed in earlier sections of the book with management of clinical diseases. This allows a discussion of pharmacological concepts from a different perspective than basic pharmacology, because drugs that are used throughout veterinary medicine in applications under different clinical scenarios often need further explanation. To accomplish our goals, experts in the clinical specialty areas and pharmacologists with expertise in specific areas have contributed tremendously to this edition of the textbook. A number of “traditional chapters” were completely revamped and revised by new contributors and other previous chapters were updated. We have attempted to provide an international perspective to this new edition by adding international authors and including drugs that have been used all over the world.

Veterinary pharmacology is in the process of great change and advancement. For many years, veterinary pharmacology was simply an extension of human pharmacology as common human medications were extrapolated for use in animal diseases. However, in the new millennium, there has been a greater emphasis by the pharmaceutical companies toward developing animal-specific drugs for their unique indications. Many of these include treatment aimed at quality of life issues in companion animals. As in previous editions, many human drugs—used off-label in animals—also are discussed, with an emphasis on the importance of interspecies differences. Sophisticated therapeutic approaches are being developed and utilized on a routine basis. New drug entities are being used and a more precise utilization of existing medications is employed in clinical practice. Antimicrobial and antiparasitic drugs must be used in a more intelligent and prudent fashion to avoid development of resistance that can impact both animals and human public health. Human food safety concerns regarding drugs used in food-producing animals have taken on increased concern. All these developments lead to both growth and a broadening of this discipline, which is central to the practice of veterinary medicine.

One of the most important applications of this textbook will be as a supplement and reference source for instructors teaching veterinary pharmacology to professional veterinary students, graduate students, and veterinary technicians. To accommodate this use, the chapters have been organized logically in an order and format that will support the teaching of veterinary pharmacology to students. Whenever possible, helpful tables, diagrams, and charts are provided to facilitate learning. Teaching veterinary pharmacology to students has changed tremendously since the early editions of this textbook. Because of the tremendous explosion in the number of drugs available, it is no longer possible to cover every drug and every indication in a veterinary course. Therefore, this book is intended to be a supplement to a veterinary pharmacology course for the student to have access to more in-depth and comprehensive information than can be presented in course lectures.

In addition to the many authors that have contributed to this edition of Veterinary Pharmacology and Therapeutics, we owe a special thanks to the previous editor, and consulting editor for this edition, H. Richard Adams. We are proud to carry on as editors with the hope of continuing the excellence and quality that was a characteristic of the editions that he edited. We are also appreciative of the support of the publishers at Wiley-Blackwell. Among these individuals, special thanks go to Dede Andersen, Antonia Seymour, Jill McDonald, and Nancy Simmerman. We also thank Luann Kublin and especially Jeneal Leone, administrative assistants at CCTRP-NCSU, for their help in processing these chapters.

Jim E. Riviere
Mark G. Papich

SECTION 1

Principles of Pharmacology

CHAPTER 1

VETERINARY PHARMACOLOGY: AN INTRODUCTION TO THE DISCIPLINE

JIM E. RIVIERE AND MARK G. PAPICH

History of Pharmacology
Veterinary Pharmacology
Regulations
What Is Veterinary Pharmacology?

Pharmacology is the science that broadly deals with the physical and chemical properties, actions, absorption, and fate of chemical substances termed drugs that modify biological function. It is a discipline that touches most areas of human and veterinary medicine and closely interfaces with pharmaceutical science and toxicology.

HISTORY OF PHARMACOLOGY

As long as humans and their animals have suffered from disease, chemical substances have played a role in their treatment. Substances obtained from plants and animals or their products were used according to precise prescriptions through antiquity. The mechanism attributed to why these substances worked are deeply rooted in the beliefs and mythologies of each culture, as were the rituals involved in their preparation.

The early history of pharmacology parallels human efforts to compile records of ailments and their remedies. The earliest recorded compilation of drugs, the Pen Tsao, consisted of a list of herbal remedies compiled in the reign of Chinese Emperor Shennung in 2700 B.C. Classic examples of medicinal use of chemicals, herbs, and other natural substances are found in the recorded papyri of ancient Egypt. The Kahun papyrus, written about 2000 B.C., lists prescriptions for treating uterine disease in women and specifically addresses veterinary medical concerns. The Ebers papyrus, written in 1150 B.C. is a collection of folklore covering 15 centuries of history. It is composed of over 800 prescriptions for salves, plasters, pills, suppositories, and other dosage forms used to treat specific ailments.

The ancient Greek philosopher-physicians of 500 B.C. taught that health was maintained by a balance of “humors,” which were affected by temperature, humidity, acidity, and sweetness, rather than to the direct actions of gods or demons. Disease was treated by returning these humors to a proper balance. Hippocrates (460–370 B.C.) was an ancient Greek physician of the Age of Pericles. He is referred to as the “father of medicine” in recognition of his lasting contributions to the field as the founder of the Hippocratic school of medicine. He was a firm believer in the healing powers of nature, conducted systematic observations of his patients’ symptoms, and began moving the practice of medicine from an art to a systematic clinical science. The first true material medica, a compilation of therapeutic substances and their uses, was compiled in 77 A.D. by Aristotle’s student Dioscorides, while serving as a surgeon in Nero’s Roman Legion traveling throughout the Mediterranean. This served as the basis for the later works of Galen (131–201) that emerged as the authoritative material medica for the next 1,400 years! In fact, some pharmaceutical preparations consisting of primarily herbal or vegetable matter are still referred to as galenical preparations. As the Dark Ages descended upon Europe, such scholarship transferred to Byzantium, where in fact a veterinary compilation for farm animal treatments, Publius Vegetius, was compiled in the 5th century.

It took until the Renaissance to awaken the spirit of discovery in Europe. The Swiss physician Theophrastus Bombastus von Hohenheim (1492–1541), known as Paracelsus, introduced the clinical use of laudanum (opium) and a number of tinctures (extracts) of various plants, some of which are still in use today. He is remembered for using drugs for specific and directed purposes, and for the famous dictum “All substances are poisons; there is none which is not a poison. The proper dose separates a poison from a remedy.” As these practices took root, official compilations of medicinal substances, their preparation, use, and dosages, started to appear in Europe. These publications, termed pharmacopeia, provided a unifying framework upon which the pharmaceutical sciences emerged. The first printed pharmacopeia, titled the Dispensatorium was published by Valerius Cordus in 1547 in Nuremberg, Germany. Local publications emerged in different European cities, with two pharmacopeias published in London in 1618. The Edinburgh Pharmacopoeia published in 1689 became the most influential during this period. It took until the mid-19th century before truly national pharmacopeias took hold, with the first United States Pharmacopeia published in 1820. The first United States Pharmacopeia has been given the title USP-0; the current edition of the United States Pharmacopeia is titled USP-30. There was also a British pharmacopeia published in 1864 and the British Pharmacopeia continues to be published today.

The history of pharmacology parallels the development of modern medicine and the realization that specific natural products and substances may cure specific diseases. The 16th and 17th centuries were marked by great explorations and the beginning of medical experimentation. In 1656, Sir Christopher Wren made the first intravenous injection of opium in a dog. The bark of the cinchona tree was brought by Jesuits from South America for use of treatment of malaria. In 1783, the English physician William Withering reported on his experience in the use of extracts from the foxglove plant to treat patients with “dropsy,” a form of edema most likely caused by congestive heart failure.

In the early 1800s the French physiologist-pharmacologist Megendie, working with the pharmacist Pelletier, studied the effects of intravenous injections of ipecac, morphine, strychnine, and other substances on animals. Megendie was the first to prove that chemicals can be absorbed into the vascular system to exert a systemic effect. A prolific scientist, he also published a formulary that survived through eight editions from 1821–1836. The Spanish physician Orfila published the results of many experiments in a book entitled Toxicologie Generale in 1813. A student of Megendie, the famous physiologist Claude Bernard, and others showed in the mid-1800s that the active ingredient of foxglove botanical preparations was digitalis, and its action was on the heart. We continue to use digoxin today for the treatment of congestive heart failure in humans and animals. The important aspect of these early studies was that they used the experimental paradigm for demonstrating chemical activity, establishing both the philosophy and methods upon which the discipline of modern pharmacology is based.

The term Pharmakologie was applied to the study of material medica by Dale in London as early as 1692; however, it is generally regarded that the biochemist Rudolph Buchheim in the Baltic city of Dorpat established the first true experimental laboratory dedicated to pharmacology in the mid-18th century. He published some 118 contributions on a variety of drugs and their actions, and argued for pharmacology to be a separate discipline distinct from material medica, pharmacy, and chemistry. His work included in 1849 a textbook Beiträge zur Ärzneimittellehre, which classified drugs based on their pharmacological action in living tissue. He deleted traditional remedies if he could not demonstrate their action in his laboratory. This is the beginning of what we now know as evidence-based pharmacology, which requires that a chemical be termed a drug only if a specific action in living tissues can be demonstrated.

His student, Oswald Schmiedeberg, became a Professor of Pharmacology at the University of Strasbourg in 1872 and took upon himself the goal of making pharmacology an independent scientific discipline based upon precise experimental methodology that ultimately displaced material medica in medical school curriculums throughout Europe by the end of the 19th century and by the early 20th century in America. He studied the correlation between the chemical structure of substances and their effectiveness as narcotics. He published some 200 publications as well as an authoritative textbook in 1883 that went through seven editions. This text classified drugs by their actions and separated experimental pharmacology from therapeutics. In addition he founded and edited the first pharmacology journal Archiv für experimentelle Pathologie und Pharmakologie in 1875, which in 2007 published volume 375 as Naunym-Schmiedeberg’s Archives of Pharmacology. His more than 150 students spread the discipline of pharmacology throughout Europe and America.

One of his students, Dr. John Abel, held the first fulltime professorship in pharmacology at the University of Michigan and is considered by some to be the father of American pharmacology. Professor Abel then moved to Johns Hopkins Medical School where he continued his basic pharmacological research and founded the Journal of Biological Chemistry as well as the Journal of Pharmacology and Experimental Therapeutics. He was instrumental in founding the American Society of Pharmacology and Experimental Therapeutics in 1908.

From these origins, the various disciplines of pharmacology grew, the common factor being the focus in experimental methods to discover and confirm drug actions. Today, the basic philosophy remains unchanged, although modern techniques are grounded in analytical chemistry, mathematical models, and the emerging science of genomics.

VETERINARY PHARMACOLOGY

The development of veterinary pharmacology generally paralleled that of human pharmacology. However, there is archeological evidence of an Indian military hospital for horses and elephants from 5000 B.C., at which time there also existed an extensive medical education program at the Hindu university at Takkasila. The formal discipline of veterinary pharmacology has its origins in the establishment of veterinary colleges and hospitals in France, Austria, Germany, and the Netherlands in the 1760s as a response to epidemics of diseases such as rinderpest that decimated animal populations throughout Western Europe. The Royal College of Veterinary Surgeons was established in London in 1791 followed in 1823 by the Royal (Dick) School of Veterinary Studies in Edinburgh. The earliest veterinary colleges were established in the United States in 1852 in Philadelphia and in Boston in 1854; however, both were short-lived. Modern existing North American veterinary schools founded in the late 1800s, and which continue in operation, include those in Iowa, Ohio, Ontario, Pennsylvania, and New York.

In these early colleges, teaching of pharmacology in veterinary schools was essentially material medica, and remained closely aligned with parallel efforts occurring in medical schools, especially when colleges were colocated on the same campuses. This was evident in the European schools, with a separation really occurring in the 20th century. However, this linkage was not absolute. An early mid-19th century veterinary textbook The Veterinarian’s Vade Mecum was published by John Gamgee in England. It was essentially a material medica and did not reflect the biological-based classification system for substances used by Professor Buchheim in the same period. The first American professor of therapeutics at the School of Veterinary Medicine at Iowa State was a physician, D. Fairchild. Similarly, a textbook of veterinary pharmacology Veterinary Material Medica and Therapeutics published by the School of Veterinary Medicine at Harvard was authored by Kenelm Winslow, a veterinarian and physician. This book, an 8th Edition of which was published in 1919, began to follow the modern thrust described earlier of relating drug actions to biological effects on tissues. It seems veterinary medicine’s 21st-century preoccupation with the “one-medicine” concept has deep historical roots.

The important event, which fully shifted veterinary pharmacology from one focused on material medica to the actual science of pharmacology, was the publication by Professor L. Meyer Jones in 1954 of the 1st Edition of the textbook you are now reading. From this point forward, veterinary pharmacology positions have existed in Colleges of Veterinary Medicine throughout the world, the structure of which are often a reflection of local university history, priorities, and academic structure.

Organized veterinary pharmacology occurred rather simultaneously in Europe and the Americas. The American Academy of Veterinary Pharmacology and Therapeutics (AAVPT) was founded in 1977 and the European Association for Veterinary Pharmacology and Toxicology (EAVPT) in 1978. These two organizations, together with the British Association for Veterinary Clinical Pharmacology and Therapeutics, launched the Journal of Veterinary Pharmacology and Therapeutics (JVPT) in 1978. Its founder, Dr. Andrew Yoxall, hoped that the journal would improve coordination and communication among pharmacologists and veterinary clinicians, and designed it for the publication of topics relating both to the clinical aspects of veterinary pharmacology, and to the fundamental pharmacological topics of veterinary relevance. Now in its 30th year of publication, and also cosponsored by both the American College of Veterinary Clinical Pharmacology (ACVCP) and the Chapter of Veterinary Pharmacology of the Australian College of Veterinary Scientists, this journal remains the primary outlet for publication of veterinary-related science-based pharmacology investigations.

The discipline of clinical pharmacology is more directly related to applying pharmacological principles—particularly pharmacokinetics—to clinical patients. Fellows of the AAVPT formed the AVMA-recognized board certified specialty—the American College of Veterinary Clinical Pharmacology (ACVCP)—in 1991. The establishment of the ACVCP paralleled the establishment of the American Board of Clinical Pharmacology (ABCP)—the human medical counterpart—in the same year with the cooperation of the American College of Clinical Pharmacology.

REGULATIONS

A different perspective of the development of veterinary pharmacology over the last century is the development of regulatory bodies to insure that safe, effective, and pure drugs reach commerce. As discussed above, material medica and pharmacopeia were in large part the force that held pharmacology together as a discipline for centuries. Since 1820, the United States Pharmacopeia (USP