Pharmacology review
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Pharmacology Review. Dosage forms. Tablets Powder-compressed Enteric-coated-protective coating Chewable-mixed with flavorings Sustained-release-released slowly over time Boluses-larger powdered tablets Capsules-loose powder in gelatin shell

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Pharmacology Review

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Pharmacology review

Pharmacology Review


Dosage forms

Dosage forms

  • Tablets

    • Powder-compressed

    • Enteric-coated-protective coating

    • Chewable-mixed with flavorings

    • Sustained-release-released slowly over time

  • Boluses-larger powdered tablets

  • Capsules-loose powder in gelatin shell

  • Suppositories-designed for absorption through rectal wall


Dosage forms1

Dosage forms

  • Liquids

    • Solutions-drug dissolved in solvent

      • Elixirs-sweetened alcohol based

      • Syrups-sweetened sugar based

    • Suspensions

      • Emulsions-oil based

      • Gels-drug suspended in semi-solid medium

    • Topicals

      • Ointments-petroleum based-forms barrier

      • Creams-liquefies at body temps

      • Paste-semisolid, stays solid at body temps


Dosage forms2

Dosage forms

  • Injectables

    • Ampule-single use, must break container

    • Vials

      • Single dose

      • Multidose

    • Repository forms-designed for release over time from injection site

    • Implants-sterile hypodermic tablets


Prescription label

Prescription Label

  • Vet clinic name, address and phone

  • Prescribing Dr. name

  • Patient name

  • Date dispensed

  • Dosing instructions

  • Medication name, strength and qty

  • Number of refills

  • Slaughter withdrawal times (if applicable)

  • Childproof container unless written documentation from client (decline such containers)


Controlled substances

Controlled Substances

  • Required by DEA due to potential for addition in humans

  • Capital C followed by roman numeral

    • CI-marijuana, LSD

    • CII-Morphine, pentobarb.

    • CIII-hydrocodone, thiopental, ketamine

    • CIV-phenobarb, diazepam, torb

    • CV-codiene syrups

  • Locked, immovable area with inventory log book


Patient 5 rights

Patient 5 Rights

  • Right patient

  • Right drug

  • Right route

  • Right dose

  • Right time


Compounding drugs

Compounding Drugs

  • Compounding for economic benefit of vet not permitted

  • Considered not approved drug

  • Vets assume all risks

  • Can’t be sold to other practices


Extra label use

Extra Label Use

  • Use of a drug in a way not defined on label

  • Vets have wide latitude but assume all responsibility

  • FDA considers legit

    • Dx with CP relationship

    • No drug specifically labeled to tx cond.

    • Procedures in place to ensure the identity of animals treated for purposes of monitoring

    • Extended withdrawal time from tx animals

    • Drug adequately labeled to ensure safe and proper use


Pharmacokinetics

Pharmacokinetics

  • Movement of drugs or chemicals within the body

    • Absorption

    • Distribution

    • Biotransformation

    • Elimination


First pass effect

First Pass Effect

  • Bioavailability

    • Percent of a drug that is absorbed and reaches the systemic circulation

    • Drugs given IV have 100% bioavail.

    • Drugs given orally have lowest bioavail.

      • Must pass through hepatic portal system first

      • Liver acts on drugs before they are distributed to target tissues (First pass effect)

      • Dosages unusually much higher to account for this


Bioavailability affected by

Bioavailability Affected By

  • Absorptive surface area

  • Blood supply to area of administration

  • Solubility of drug

    • pKa –specific pH at which 50% of drug are ionized

    • Hydrophilic

    • Lipophilic

  • Distribution of drugs in body tissues

    • Example-for drugs to leave capillaries in brain must be lipophilic (blood brain barrier)

  • Biotransformation of drugs

    • Altering drug before it can be eliminated

      • Phase I-chemical transformation (oxidation, reduction, hydroloysis) Most drug metabolites are less biologically active after phase I

      • Phase II-enzymatic conjugation of metabolite into a hydrophilic molecule

  • Elimination of drugs from body tissues

    • Kidney and liver

    • Half life


Pharmacodynamics

Pharmacodynamics

  • Physiological effects of drug on the body system into which it has been admin.

  • AKA mechanism of action

  • For (most) drugs to exert an effect they must bind to specific receptor

    • Lock and key principle

    • Agonist/antagonist

  • Nonreceptor-mediated reactions

    • Osmotic diuretics-active molecules that are filtered into the urine and not reabsorbed

    • Chelators-binds to ions or blood compounds and inactivates them

    • Antactids-directly reduces stomach acid


Therapeutic range index

Therapeutic Range/Index

  • Ideal range of a drug concentration within a body that provides a desired effect without signs of toxicity

    • Above=toxic

    • Below=subtherapeutic

    • Wider range=safer drug

    • Goal is to maintain levels in therapeutic range


Nervous pharmacology

Nervous Pharmacology

  • Nervous System

    • CNS

    • PNS

      • Somatic

      • Autonomic

        • Sympathetic

        • Parasympathetic

  • Work by altering one or more of systems

    • Mimicking neurotransmitters

    • Preventing neurotransmitter release (presynaptic)

    • Blocking neurotransmitter binding (postsynaptic)

    • Inhibiting reuptake or breakdown of neurotransmitter


Cns drugs

CNS Drugs

  • General

    • Anesthesia

    • Analgesia

    • CNS excitation/stimulation

    • Control seizures

    • Cause euthanasia

  • Categories

    • Tranqs (Phenothiazines) (Benzodiasepaines) (Alpha 2 agonists)

    • Barbs (Long (8-12 hrs), short (45 min-1.5 hrs) and ultrashort acting)

    • Dissociatives (Cyclohexamines)

    • Opiods (Analgesia and sedation) (5 receptors-alpha, sigma, kappa, delta and epsilon unknown effects)

    • Neuroleptanalgesics (combines effects of opiods and tranqs)

    • Antisiezure

    • CNS stimulants (Doxapram-reversal of resp depression/apnea)

    • Euth agents


Nervous pharmacology cont

Nervous Pharmacology Cont.

  • Cholinergic Agents

    • Stimulate acetylcholine receptors

      • Directly (mimicking)

        • Bethanechol

        • Pilocarpine

        • Metoclopramide (reglan)

      • Indirectly (preventing AchE)

        • Organophosphate compounds

        • edrophonium

    • Uses

      • Stimulate GI motility

      • Treat urinary retention

      • Reduce intraocular pressure

      • Control vomiting

      • Diagnosis myasthenia gravis

    • Adverse effects

      • Bradycardia

      • Hypotension

      • SLUDD (parasympathetic NS)


Nervous pharmacology cont1

Nervous Pharmacology Cont.

  • Anticholinergic agents

    • Block the effects of acetylcholine

      • Atropine

      • Glycopyrolate

      • (aminopentamide (centrine)

    • Usage

      • Preanesthetic to dry secretions and prevent bradycardia

      • Tx diarrhea and vomiting

      • Dilation of pupils for exam

      • Tx of bradycardia

    • Adverse effects

      • Drowsiness

      • Tachycardya

      • Constipation

      • anxiety


Nervous pharmacology cont2

Nervous Pharmacology Cont.

  • Adrenergic Agents

    • Mimic effects of epi and norepi

      • Epinephrine (stimulate both alpha and beta

      • Norepi

      • Isoproterenol (pure beta agonist-bronchodialator)

      • Dopamine (precursor to epi and norepi)

      • PPA

      • Terbutaline (Brethine)

      • Xylaxine (rompun-alpha agonist with sedative properties)

      • Medetomidine (Domitor-alpha agonist with sedative properties)

    • May be alpha (excitatory) or beta (inhibitory) agonists

    • Usage

      • Stimulate HR

      • Reverse hypotension and bronchoconstriction

      • Strengthen heart contractions

      • Treat urinary incontinence

      • Prolong effects of locals (vasoconstric. Reduces absorption)

    • Adverse effects

      • Hypertension

      • Nervousness

      • Cardiac arrhythmias


Nervous pharmacology cont3

Nervous Pharmacology Cont

  • Adrenergic blocking agents

    • Block the effects of epi and norepi

    • Classified

      • Alpha blockers

        • Ace (tranquilizer)

        • Yohimbine (reversal for xylazine)

        • Atipamezole (Antesedan)

      • Beta blockers

        • Propanolol

          • Tx hypertrophic cardiomyopathy

      • Adverse effects

        • Hypotension

        • Heart block


Antibiotics

Antibiotics

  • Spectrum of activity

    • The range of different bacteria affected by a given abx

    • Gram + vs. gram –

  • Mechanism of action

    • Bacterialcidal

    • Bacteristatic

  • C & S


Penicillins

Penicillins

  • Pharmokinetics

    • Absorption of oral preps in stomach and duodenum

    • Rapid distrib. Into tissues

    • Excreted by kidneys

    • Some passage into milk

  • Mechanism of action

    • Bacterialcidal

      • Inhibits cell wall synthesis

      • Gram + bacteria have cell wall that is unprotected

      • Gram – bacteria have no outer membrane that protects cell wall


Penicillins1

Penicillins

  • Narrow spectrum

    • Pen G

  • Beta-lactamase-resistant pens

    • Not used in vet med (expensive)

    • For pen resistant bacteria

    • For highly resistant staph

  • Broad spectrum

    • Ampicillin

    • Potentiated pens

      • Clavamox

      • Wider range of bacteria


Cephalosporins

Cephalosporins

  • Pharmokinetics

    • Distributed to all body except CNS

    • Metabolized by liver

    • Excreted by kidney

  • Mechanism of action

    • Bacterialcidal

      • Inhibits cell wall synthesis

      • Similar spectrum of activity as pens

  • Common uses

    • Cystitis

    • Skin infections

    • mastitis


  • Cephalosporins cont

    Cephalosporins Cont.

    • Preparations

      • Cephalexin (Keflex)

        • Most commonly used

        • May cause vomiting

      • Cefadroxil (Cefa tabs)

      • Cefazolin (Ancef)

      • Ceftiofur (Naxcel)

        • 2nd generation

      • Sefpodoxime (Simplecef)

        • 3rd generation

        • SID tx


    Tetracyclines

    Tetracyclines

    • Pharmacokinetics

      • Rapid distribution into most body tissues

      • Very little metabolism occurs

      • Excreted by kidney in active form

    • Pharmacodynamics

      • Bacteriostatic

      • Inhibit bacterial cell division

      • Both gram + and gram – affected

      • Considered broad spectrum abx

    • Common uses

      • Respiratory and enteric infections


    Tetracyclines cont

    Tetracyclines Cont.

    • Preparations

      • Tetracycline (panmycin)

      • Oxytetracycline

      • Chlortetracycline

      • Doxycycline

        • Most potent broad spectrum in class

    • Important info

      • May cause permanent staining of teeth enamel in young animals

      • Inhibited by milk, antacids and pens

      • Becomes toxic after exp date


    Aminoglycosides

    Aminoglycosides

    • Pharmacokinetics

      • Poorly absorbed through GI tract

      • Rapid distribution occurs into ECF

      • Doesn’t reach CSF or fetal tissues

      • May accumulate in renal cortical tissues

      • Nephrotoxic if not cleared adequately

    • Pharmacodymamics

      • Bacteriostatic

      • Inhibit bacterial cell division

      • Considered broad spectrum

      • Mostly effective against gram -


    Aminoglycosides cont

    Aminoglycosides Cont.

    • Common usage

      • Infections of resp, repro, renal, skin and ocular systems

    • Preparations

      • Neomycin

      • Gentamycin (Gentocin)

      • Amikacin (Amiglyde-V)

    • Important info

      • Highly ototoxic and nephrotoxic

      • Not approved for food prod. animals


    Fluoroquinolones

    Fluoroquinolones

    • Pharmacokinetics

      • Good bioavailability after oral and perenter admin.

      • Distributed to therapeutic levels in nearly all body tissues

      • Metabolized by liver

      • Excreted by kidney and bile

    • Pharmacodynamics

      • Bacterialcidal

      • Inhibition of bacterial DNA-gyrase


    Fluoroquinolones cont

    Fluoroquinolones Cont.

    • Considered very broad spectrum

    • Gram – and gram +

  • Usage

    • Skin, soft tissue, respiratory, UTI

    • Approved for resp dz in cattle

    • Approved for E coli in poultry

  • Preparations

    • Enrofloxacin (Baytril)

    • Orbifloxacin (Orbax)

    • Marbofloxacin (Zeniquin)

    • Difloxacin (Dicural)


  • Fluoroquinolones cont1

    Fluoroquinolones Cont.

    • Deleterious effects to articular cartilage in young, growing animals

    • Inhibited by milk and antacids

    • Enrofloxacin induced blindness (rare)


    Miscellaneous abx

    Miscellaneous Abx

    • Chloramphenicol

      • Broad spectrum, rapidly absorbed into most tissues including CNS and glands

    • Florfenicol (Nufuor)

      • Similar to chloramphenicol

      • Inj used for bovine resp dz

      • Extra label use in tx calf scours


    Macrolides and lincosamides

    Macrolides and Lincosamides

    • Primary for gram +

    • Clindamycin is also very effective agains anaerobic bacteria

    • Uses resp and skin infections

    • Preparations

      • Tylosin (Tylan)

      • Erythromycin (Lincosin)


    Sulfonamides

    Sulfonamides

    • Broad spectrum of activity

    • Gram + and gram –

    • May be potentiated by addition of trimethoprim or ormethoprim

    • Uses UTI, resp, coccidiosis

    • Preparations

      • Sulfadimethoxine (Albon)

      • Trimethoprim sulfa (Tribrissen)

      • Trimethoprim sulfamethozazole (Bactrim)

      • Ormethoprim sulf (Primor)

    • Important info

      • KCS potential side effect


    Antifungals

    Antifungals

    • Imidazoles

      • Systemic and dermal fungal infections

      • Preparations

        • Ketoxonazole (Nizoral)

        • Miconazole (Monostat and conofite)

        • Clotrimazole (Lotrimin, tinactin)

        • Griseofulvin-superficial fungal infections (ringworm primarily) (Absorption enhanced by fatty meal)


    Antivirals

    Antivirals

    • Acyclovir

      • Used in cats for herpes virus conjunctivitis

    • Interferon

      • Chronic FELV infections


    Parasiticides

    Parasiticides

    • Benzimidazoles

      • Broad spectrum

      • Usage-almost all internal parasites are susceptible to this class (except small animal tapes)

      • Ok to use in exotics like fish and birds

      • Preparations

        • Fenbendazole (Panacure)

        • Albendazole (Valbazen)

        • Thiabendazole (Omnizole)


    Parasiticides1

    Parasiticides

    • Organophosphates

      • Limited use due to side effects

        • SLUDD

        • Atropine antidote

      • Usage

        • Highly effective against equine stomach bots

        • Effective for resistant whipworm and hookworm infections in dogs

      • Preparations

        • Trichlorphon (Combot, Equibot)

        • Dichlorvos (Task, Atgard)


    Parasiticides2

    Parasiticides

    • Imidazothiazoles

      • Usage

        • Many parasites susceptible

        • Most commonly used in large animals

      • Preparations

        • Febantel

          • Component of Drontal Plus

        • Levamisole (Tramisol, Levasole)


    Parasiticides3

    Parasiticides

    • Avermectins

      • Several OTC prods available for livestock

      • Usage

        • Effective against most parasites in large animals

          • Internal and External

        • Common HW monthly prev.

      • Preparations

        • Ivermectin (Heartgard, Ivomec, Eqvalan)

          • Use with caution in collies and collie mixes

            • Lack gene that pumps it out of the brain

            • Drug accumulates and causes seizures, coma etc.

          • Moxidectin (proheart, Quest)

          • Dormactin (Dectomax)

          • Selamectin (Revolution)

            • Spot on for dogs and cats


    Parasiticides4

    Parasiticides

    • Tetrahydropyrimidines

      • Most common dewormer

      • OTC

      • Roundworm species susceptible

      • Not effective for whips or hooks

      • Preparations

        • Pyrantel pamoate (Nemex, Strongid-T)


    Parasiticides5

    Parasiticides

    • Anticestodals

      • Treatment of tapeworm infections in dogs and cats

      • Preparations

        • Praziquantel (Droncit)

        • Epsiprantel (Cestex)


    Parasiticides6

    Parasiticides

    • Antiprotozoals

      • For tx of coccidia and giardia

        • Large and small animals

      • Preparations

        • Coccidiostats

          • Monensin (Coban 60) poultry

          • Amprolium (Corid) cattle

          • Sulfadimethoxine (Albon)

        • For giardia

          • Metronidazole (Flagyl)


    Parasiticides7

    Parasiticides

    • Heartworms

      • Tx involves removal of adult heartworms first then removal of juveniles (microfilaria)

      • Once infections have been treated should be on monthly HW prev.

      • Adulticides

        • Thiacetarsemide (Caparsolate)

          • Arsenical compound given IV in 4 doses

          • Can be hepatotoxic

          • Cheap

        • Melarsomine dihydrocholoride (immiticide)

          • Aresenical compound given deep IM in backless irritating to tissues

          • More expensive

          • Not hepatotoxic


    Parasiticides8

    Parasiticides

    • HW Preventatives

      • Monthly kill retroactively

      • Vary in combinations

        • Often tx other parasites as well

      • Preparations

        • Ivermectin (Heartgard)

          • HG + treats and prevents rounds too

        • Mibemycin oxime (Interceptor, Sentinel)

          • Controls hooks, whips and rounds

          • Sentinel contans lufenuron for fleas

        • Moxidectin (Proheart)

          • Many restrictions


    Parasiticides9

    Parasiticides

    • HW Preventatives

      • Selamectin (Revolution)

        • Topical

        • Also tx earmites, sarcoptic mange, hookworms and roundworms

      • Diethylcarbamazine (Filaribits)

        • Daily

        • Not commonly used anymore


    Parasiticides10

    Parasiticides

    • Ectoparasites-read labels and use in caution with young, nursing or pregnant and certain species.

    • Monthly prev.

      • Fipronil (Frontline topspot)

      • Imidacloprid (Advantage, K9 Advantix-has 44% permethrin so don’t use in cats!)

      • Lufenuron (Program and Sentinal)

        • Oral tablets

        • Fleas must eat a blod meal

      • Permethrin (Defend, K9 Advantix)

        • Topical

        • Not for cats

      • Selamectin (Revolution)

        • Also tx earmites, sarcoptic mange, hookworms and rounds


    Parasiticides11

    Parasiticides

    • Insecticides

      • Pyrethrins

        • Quick kills-fast knockdown

        • Safe for most animals

        • Very toxic to cats

      • Chlorinated hydrocarbons

        • Banned due to bald eagles

      • Carbamates (mycodex, sevin dust)

      • Organophosphates

        • Chylorpyfiros

        • Dichlorovos (Vet Kem)

        • Diazinon (Escort)


    Parasiticides12

    Parasiticides

    • Insecticides Cont.

      • Neonicotinoids

        • Nitenpyram (Capstar)

          • Single oral dose kills fleas on pet within 30 mins

        • Formamidines

          • Amitraz (Mitaban, Preventic)

        • IGRs

          • Preparations

            • Methoprene

            • Fenoxycarb

            • Nylar


    Respiratory drugs

    Respiratory Drugs

    • Principles

      • Control of secretions

        • Expectorants

        • Mucolytics

      • Control of reflexes

        • Coughing

        • Sneezing

        • Bronchospasms

      • Maintaining adequate airflow through alveoli

        • Reverse bronchoconstriction

        • Remove pulmonary edema

        • Clearing mucus from airways


    Respiratory drugs1

    Respiratory Drugs

    • Expectorants

      • Liquefy and dilute mucus

      • Most given in combo with other drugs

      • Act directly on mucus secreting glands

        • Guaifenesin (Triaminic, Robitussin-AC)

          • Used as induction agent for horses (only species with anesthetic properties)


    Respiratory drugs2

    Respiratory Drugs

    • Mucolytics

      • Decrease the viscosity of mucous

      • Act directly on mucous secretions

        • Acetylcystine (Mucomyst)

          • Nebulization (RR problems)

          • Antidote for acetaminophen toxicity


    Respiratory drugs3

    Respiratory Drugs

    • Antitussives

      • Suppress or inhibit cough

      • Butorphanol tartrate

        • C-IV controlled substance

        • Partial opiate agnoist/antagonist

        • Antitussive in dogs

        • Analgesic in dogs, cats and horses

        • Preanesthetic in dogs and cats


    Respiratory drugs4

    Respiratory Drugs

    • Antitussives Cont.

      • Hydrocodone bitartrate (Hycodan)

        • C-III controlled substance

        • Opiate agonist

        • Antitussive in dogs (good for dry hacking cough)

      • Codeine

        • C-II controlled substance

        • Not common in vet med

        • Opiod agonist


    Respiratory drugs5

    Respiratory Drugs

    • Antitussives Cont.

      • Trimeprazine tartrate (Temeril-P)

        • Combo drug with pred

        • Commonly used to tx feline asthma

        • Has significant antipruritic properties


    Respiratory drugs6

    Respiratory Drugs

    • Bronchodilators

      • Act to increase the diameter of bronchioles by preventing bronchoconstriction

        • 3 mechanisms of constriction

          • Parasympathetic stimulation

            • Atropine

            • Glycpyrrolate

            • Limited use in treating bronchoconstriction

          • Histamine release during allergic or inflammatory responses

            • Prevent binding of histamine to H1 receptors in smooth muscle

            • Diphenhydramine

            • Hydroxyzine

          • Blockage of sympathetic stimulation

            • Have direct sympathetic effect on bronchioles

            • Beta 1-stimulates heart

            • Beta 2-causes bronchodilation

            • Epi (both beta 1 & 2 activity)

            • Albuterol (beta 2)

            • Terbutaline (beta 2)


    Respiratory drugs7

    Respiratory Drugs

    • Bronchodilators Cont.

      • Methylxanthines

        • Have an indirect effect on bronchioles

        • Theophylline

        • Aminophylline

        • Caffeine and theobromine are naturally occurring methylxathines


    Respiratory drugs8

    Respiratory Drugs

    • Miscellaneous Resp. Drugs

      • Doxapram

        • Direct effect

        • Used commonly to restore respiration in animals after prolonged anesthesia

        • Neonates sublingually


    Anti inflammatory drugs

    Anti-inflammatory Drugs

    • NSAIDS

      • Inhibit the production of prostaglandins

    • Antihistamines

      • Block the binding of histamine from tissue receptors

    • Corticosteroids

      • Inhibit prostaglandins at a higher level in the reaction pathway


    Anti inflammatory drugs1

    Anti-inflammatory Drugs

    • NSAIDS

      • Inhibit the production of prostaglandins

        • Inflammatory process (COX 2)

          • Associated with pain and fever

        • GI mucus production (COX 1)

          • Inhibition leads to ulcers, nephrotoxicity at high doses and anti-platelet activity

        • LOX inhibitor (dual inhibitor)

          • This enzyme pathway leads to the formation of additional inflammatory cytokines in response to injury

      • Caution

        • Those predisposed to GI ulcers

        • Don’t use with corticosteroids


    Nsaids

    NSAIDS

    • Acetylsalicylic acid

      • Non-selective COX inhibitor

      • Asprin

      • Poorly metabolized in the cat

    • Phenylbutazone

      • Non-selective COX inhibitor

      • Used primarily in horses and dogs


    Nsaids1

    NSAIDS

    • Flunixin Meglumine

      • Non-selective COX inhibitor

      • Banamine

    • Carprofen

      • Selective COX 2 inhibitor and COX 1 sparing

      • Rimadyl

        • Nephrotoxicity with prolonged use


    Nsaids2

    NSAIDS

    • Etodolac

      • Non-selective COX inhibitor

      • EtoGesic

    • Deracoxib

      • Selective COX 2 inhibitor and Cox 1 sparing

      • Deramaxx

    • Meloxicam

      • Selective COX 2 inhibitor and Cox 1 sparing

      • Metacam


    Nsaids3

    NSAIDS

    • Tepoxalin

      • Dual inhibitor

      • Zubrin

    • Naproxen

      • Non-selective COX inhibitor

      • Naprosyn

    • Ibuprofen

      • Non-selective COX inhibitor

      • Advil

      • Don’t use in small aniamls


    Nsaids4

    NSAIDS

    • DMSO

      • Mechanism of action different than other NSAIDS

      • Traps superoxide radicals produced by inflammation

      • This reduces cellular damage caused by inflammation

      • Topical anti-inflammatory

      • Carrier substance for otic and skin preps

        • Causes vasodilatation and enhances drug transfer across epidermis


    Acetaminophen

    Acetaminophen

    • Not a NSAID

    • Not a prostaglandin inhibitor

    • Mechanism of action not known

    • Limited use in vet med.

    • 1 Tylenol can kill an average size adult cat


    Antihistamine h1

    Antihistamine (H1)

    • Block the binding of histamine from tissue receptors

    • Histamine

      • Causes dilation of small blood vessels and increased capillary permeability

      • Ultimately leads to swelling

    • H1 Blockers

    • Tripelennamine

    • Diphenhydramine

    • Hydroxyzine


    Corticosteroids

    Corticosteroids

    • Inhibit prostaglandins at a higher level in the reaction pathway

    • Anti-inflammatory

    • Immuno-suppresion

    • Increased catabolism of proteins and fats

    • Short acting (>12 hours)

      • Hydrocortisone

      • Cortisone

    • Intermediate acting (12-36 hours)

      • Prednisone

      • Prednisolone

      • Methypredinisolone

      • Trimcinolone (Vetalog)

    • Long acting (>48 hours)

      • Dexamethasone


    Renal pharmacology

    Renal Pharmacology

    • Kidneys are involved in excretion of cellular wastes and drug metabolites

    • Reabsorption of ions in the proximal tubule draws water

    • Patient sensitivity to numerous drugs is affected by kidney function

      • Dose and dose interval commonly altered in patients with renal problems


    Renal failure

    Renal Failure

    • Most common cause of non-accidental death in domestic animals

    • Disease classification

      • Prerenal

      • Renal

      • Post-renal

      • Acute

      • Chronic


    Diuretics

    Diuretics

    • Drugs that promote diuresis

      • Remove excess fluid from tissue (edema)

      • Reduce hypertension by decreasing blood volume

        • Promote sodium excretion and urine flow

      • Loop diuretics

        • Inhibit the reabsorption of sodium in the ascending limb of the loop of Henle

          • Stops the sodium pumps

        • Causes a net excretion of K+, Cl-, H2O

        • Furosemide, lasix, disal


    Diuretics1

    Diuretics

    • Osmotic diuretics

      • Concentrated soluions administered IV

      • Freely filtered by the glomerulus with no net reabsorption

      • Promote diuresis by creating high osmotic pressure within the plasma filtrate

      • Manitol 20%

      • Glucose


    Diuretics2

    Diuretics

    • Thiazide Diuretics

      • Inhibit the reabsorption of Na+, Cl- and H2O in the distal tubules

      • Longer duration of action than loop diuretics

      • Similar affects on K+ as loops

      • Chlorthiazide

      • Hydrochlorothiazide


    Diuretics3

    Diuretics

    • Potassium-sparing diuretics

      • Weaker than previously mentioned drugs

      • Antagonize the affect of aldosterone

      • Inhibit exchange of sodium for potassium in distal tubules, thus conserving K+ and leaving Na+ in urine


    Diuretics4

    Diuretics

    • Carbonic anhydrase inhibitors

      • Inhibit the ability of CO2 and H2O to bind in the proximal tubular cells

      • No H+ is available to be secreted into the filtrate

        • Bicarbonate reabsorption is dependent upon this

        • HCO3- is left in the filtrate, binds with Na+ and passes out of the body in urine

          • This is called bicarbonate diuresis

          • Lowest effective diuresis of any diuretic

          • The net result is excretion of bicarbonate, Na+, K+ and H2O


    Cholinergic agonists

    Cholinergic Agonists

    • Mimic the effect of the parasymphateic nervous system

    • Stimulate acetylcholine receptors

    • Causes contraction of smooth muscle in the bladder

    • Bethanechol

    • Overdose

      • SLUDD and tx with atropine


    Cholinergic antagonists

    Cholinergic Antagonists

    • Blocks the effects of acetylcholine

    • Causes relaxation of the smooth muscle in the bladder

    • Used to relax bladder in urge incontinence

    • Propantheline

    • Adverse effects

      • Intestinal stasis/decreased motility


    Adrenergic antagonists

    Adrenergic Antagonists

    • Drugs that inhibit he effects of the sympathetic nervous system

    • Useful in treating hypertension (reduces the pressure in the glomerulus)

    • Classified by the receptors they antagonize

      • Alpha antagonists

        • Cause vasodilatation

        • Relaxation of urethra in post renal obst.

        • Phenoxybenzamine

        • Prazosin

      • Beta antagonists

        • Cause vasodilatation

        • Propanolol


    Angiotension converting inhibitors ace inhibitors

    Angiotension-Converting Inhibitors (ACE inhibitors)

    • Alleviate hypertension

      • Decreasae vascular resistance

      • Decrease aldesterone secretion

      • Enalapril (enacard)

      • Benzepril (Lotensin)


    Antidiuretic hormone

    Antidiuretic Hormone

    • Increase permeability of collecting ducts to water

      • Water is drawn into ECF

      • Tx diabetes

      • Vasopressin


    Urinary acidifiers alkalinizers

    Urinary Acidifiers/Alkalinizers

    • Lower urine pH

    • S/D, C/D

    • DL-methionine (Methio-tabs)

    • Raise urine pH

    • U/D

    • Potassium citrate


    Erythropoietin

    Erythropoietin

    • Normally produced by renal cortex

      • Production ceases in renal failure

      • Stimulates production of RBCs in bone marrow

      • Erythropoietin (Epogen)


    Incontinence

    Incontinence

    • Lack of voluntary control of urine

    • Many causes

      • Excess contraction treat with Cholinergic Antagonists (previously discussed)

      • Weak sphincter

        • Adrenergic agonist

        • PPA

        • Proin

      • Hormonal

        • Treat with hormone depending on etiology

          • DES

          • Testosterone


    Cardiovascular drugs

    Cardiovascular Drugs

    • Terminologoy

      • Afterload is the pressure that must be overcome to empty the ventricles

      • Preload is the volume of blood in he ventricles at the end of diastole

      • Stroke volume is the quantity of blood delivered by the left ventricle with each contraction

      • Arrhythmias are any variation from normal heart rhythm

      • Preventricular contractions are contractions of the ventricles without corresponding contractions fo the atria

      • Chrontopropic refers to drugs that affect the heart rate or timing

      • Inotropic refers to a drug that affects the force of the contraction


    Objectives in tx heart dz

    Objectives in Tx Heart Dz

    • Control rhythm

    • Maintain cardiac output

      • Increase strength of contraction

      • Decrease after load

      • Decrease preload

    • Relieve fluid accumulation

      • Diuretics

      • Reduce sodium intake

    • Increase oxygenation

      • bronchodilator


    Positive inotropic drugs

    Positive Inotropic Drugs

    • Drugs that increase strength of contraction

    • Cardiac glycosides

      • Derived from plant digitalis purpurea

      • MOA

        • Increase available calcium ions in the cardiac muscle cells

        • Poison the sodium/potassium pump resulting in more calcium left inside the cell after repolarization

      • Effects

        • Increased strength of contraction

        • Decreased rate of contraction

        • Increased automaticity (antiarrythmatic)


    Positive inotropic drugs cont

    Positive Inotropic Drugs Cont.

    • Use

      • CHF

      • Atrial fibrillation

    • Preparations

      • Digoxin

    • Many drug interactions


    Catecholamines

    Catecholamines

    • Adrenergic agonists

    • MOA

      • Bind sympathetic receptors

    • Effects

      • Increased rate and strength of contractions

      • Vasoconstriction

      • Elevate blood glucose

    • Uses

      • AHF

      • Anaphylaxis

    • Preparations

      • Epi

      • Dopamine


    Antiarrhythmics

    Antiarrhythmics

    • Arrhythmias occur for many reasons but ultimately result in decreased cardiac output from poorly coordinated contractions

    • Ectopic foci of the nervous tissue that fire prior to the SA node and interfere with the normal cardiac conduction system

    • ECGs are used to evaluate electrical activity in the heart and to detect abnormalities in cardiac conduction


    Antiarrhythmics1

    Antiarrhythmics

    • Sodium infux inhibitors

      • Lidocaine

        • Prevents depolarization of the cardiac muscle fibers by limiting the Na+ infux into extopic cells

        • SA node not affected by these drugs and regain control of the heart

      • Procanamide

        • Similar MOA as lidocaine


    Antiarrhythmics2

    Antiarrhythmics

    • Beta Blockers

      • Propanolol

        • Beta adrenergic antagonist

        • Decrease sympathetic tone and prevents tachycardia

        • Also acts as a negative inotrope and must be used cautiously in patients with preexisting myocardial weakness


    Antiarrhythmics3

    Antiarrhythmics

    • Calcium Channel blockers

      • Veramamil

        • Blocks calcium channels in myocardial cells, resulting in reduced depolarization rates

        • Also causes decreased strength of contraction and reduced cardiac output

        • Limited use in vet med


    Vasodialators

    Vasodialators

    • Act by dilating arteries, veins or both

    • Reduce preload and or afterload

      • Anteriolar dilators

        • Hydralazine

          • Reduce afterload in CHF

          • Particularly useful in mitral insufficiency

      • Venodilators

        • Nitroglycerin

          • Topical

          • Reduces preload

          • Reduces pulmonary edema

      • Combo vasodilators

        • Prazosin

          • Blocks alpha adrenergic recetors

          • Reduces both preload and afterload

      • ACE inhibitors

        • Block conversion of antiotensin I to angiotensin II

        • Results in vasodilation

        • Reduction of both preload and afterload

        • Enalapril (Enacard)

        • Benzepril


    Diuretics heart

    Diuretics (Heart)

    • Reduce circulating blodo volume

    • Effectively reduce preload

    • Commonly used in heart failure

      • Furosemide

      • Chlorothiazide


    Diet heart

    Diet (Heart)

    • Control Na+ consumption in diet

      • Reduce water retention and subsequently reduce preload

    • Control weight loss commonly seen in CHF

      • Adequate levels of high biologic value protein

      • High amount of simple sugars


    Gi drugs

    GI Drugs

    • Vomiting

      • Controlled by vomiting center in the medulla oblongata

      • Vomiting center stimulated by chemoreceptor trigger zone

        • Peripheral receptors in the GI tract, pharynx etc. send impulses that result in vomiting

        • Fear and excitement may cause the cerebral cortex to stimulate the CRTZ

        • Certain drugs stimulate the CRTZ via circulation and trigger emesis

        • Toxins from metabolic waste products, bacteria or chemicals may also reach the CRTZ and cause vomiting


    Gi drugs1

    GI Drugs

    • Diarrhea has numerous causes

      • Parasites

      • Bacterial endotoxins

      • Dietary indiscretion

    • Uncontrolled, chronic diarrhea often results in dehydration and sever metabolic acidosis

    • Dietary mgmt and conservative therapy may be all that is required in acute diarrhea


    Gi drugs2

    GI Drugs

    • Emetics

      • Don’t use in patients with

        • Strong acid ingestion or caustic substances

        • Depressed pharyngeal reflexes

        • seizures

        • Respirator distress

      • Central acting emetics

        • Directly stimulate CRTZ

          • Apomorphine (Class II)

            • Injection or applied to conjunctival sac

          • Xylazine

            • IV injection

      • Locally acting emetics

        • Incite local irritation of stomach lining

          • Syrup of ipecac

            • 10-30 mins

          • Hydrogen perioxide (20% diluted soln)

            • 10-15 mins


    Gi drugs3

    GI Drugs

    • Antiemetics

      • Symptomatic tx don’t tx underlying cause

      • Phenothiazines

        • Block CRTZ

        • Chlorpromazine (Thorazine)

        • Prochloperazine (Compazine)

        • Side effects

          • Hypotension

          • Sedation


    Gi drugs antiemetics cont

    GI Drugs (Antiemetics Cont.)

    • Procainmides

      • Both central and peripheral acting

        • Block CRTZ

        • Speed gastric emptying (Local)

        • Metoclopramide

    • Antihistamines

      • Central acting

        • Diphenhydramine

    • Anticholinergics

      • Both central and peripheral acting

        • Block CRTZ and delay gastric emptying (counter productive)

        • Not used in vet med much

        • Aminopentamide (Centrine)

        • Side effects

          • Dry mm

          • Urine retention


    Gi drugs4

    GI Drugs

    • Antiulcer Meds

      • H2 receptor antagonists

        • Block histamine at level of parietal cells

        • Prevent release of hydrochloric acid

        • Cimetadine (Tagament)

        • Ranitidine (Zantac)

        • Famotidine (Pepsid AC)

    • Proton Pump Inhibitors

      • Bind at the secretory surface of the arietal cells and prevent release of H+ ions into stomach

      • Common in tx of racehorses with ulcers

        • Omeprazole (Prilosec or gastrogard)

        • Lansoprazole (Prevacid)


    Gi drugs5

    GI Drugs

    • Antacids

      • Directly neutralize stomach acid

      • Most are salts of earth metals

        • Aluminum hydroxide (Malox, mylanta)

        • Magnesium hydroxide (Milk of magnesia)

    • Gastric protectants

      • The stomach bandage

        • Disaccharide compounds that form a paste in the stomach that adheres to abraded surface of an ulcer

      • Sucralfate (Carafate)

      • Give 30 mins prior to H2 antagonists


    Gi drugs6

    GI Drugs

    • Antidiarrheals

      • Aimed at symptomatic control of diarrhea

      • Narcotic analgesics

        • Very effective in dogs

        • Limited use in cats (CNS stimulation)

        • Diphenoxylate (Lomotil)

        • Poperamide (Immodium)

      • Anticholinergics

        • No longer commonly used

        • Causes gastric stasis

        • Aminopentamide (Centrine)

      • Protectants/Adsorbants

        • These compounds bind bacteria and toxins and protect the lining of the intestine

          • Bismuth (pepto)

          • Kaolin.pectin (Kaopectate)

          • Activated charcoal (Toxiban)


    Gi drugs7

    GI Drugs

    • Laxatives

      • Hyperosmotic agents

        • Not absorbed from intestine

        • Cause osmotic draw and thus soften stool

        • Lactulose

        • Magnesium hydroxide (Milk of magnesia)

        • Phosphate salt enema (Fleet)

          • DON’T USE IN CATS

      • Bulk producing agents

        • Indigestible plant compounds that raise stool volume and draw water

          • Metamucil

          • Psyllium

          • Canned pumpkin

          • bran


    Gi drugs laxatives cont

    GI Drugs (Laxatives Cont.)

    • Lubricants

      • Orally and rectally

      • Mineral oil (colic in horses and bloat in cattle)

      • Petrolatum (laxatone)

    • Surfactant stool softeners

      • Reduce surface tension and allow water to penetrate

      • Docusate sodium (docusoft, pet-enema)


    Gi drugs8

    GI Drugs

    • Prokinetics

      • Promote intestinal motility

      • Act to enhance the action of acetylcholine in GI tract

      • 3 primary actions

        • Strengthen lower esophageal sphincter

        • Promote gastric motility

        • Promote intestinal motility

      • Tx

        • Gastric refulx

        • Delayed gastric emptying

        • Intestinal hypomotility

      • Metoclopramide (Reglan)

        • Upper GI tract mainly

        • Has antiemetic properties

        • Adverse effects in dogs and cats include behavior changes

      • Cisapride

        • Lower gi tract mainly

        • Doesn’t have antiemetic properties

        • Can only be found compounded


    Gi drugs9

    GI Drugs

    • Replace inadequate or absent digestive enzymes

      • Pancreatic enzyme replacements

        • Viokase-V

        • Pancreazyme

        • Powder should be mixed with food and let stand for 15 minutes prior to feeding


    Endocrine and hormonal drugs

    Endocrine and Hormonal Drugs

    • Adrenal

      • Corticotropin (ACTH)

        • Dx of hyper and hypo adrentocorticism

      • Desoxycorticosterone pivalate

        • Long acting mineralcorticoid

        • Tx of hypoadrentocorticism

        • Percorten-v

        • Adverese affects

          • Hypertension

          • Hypernatremia

          • Hypokalemia

      • Mitotane

        • Related to DDT

        • Used to tx hyperadrentocorticism

        • Lysodren

        • Adverse affects

          • Overdose can cause addionian crisis

      • Selegeline

        • Used to tx pituitary dependent cushings

        • Inhibits release of ACTH from pituitary gland

        • Also used to tx CDS in dogs

        • Anipryl


    Endocrine and hormonal drugs1

    Endocrine and Hormonal Drugs

    • Levothryroxine (T4)

      • Tx of choice for hypothyroidism

      • Soloxine, tyro-tabs, synthroid

    • Liothryronine (T3)

      • Used with cases don’t respond to T4

    • Methimazole

      • Interferes with iodine uptake and synthesis in the thyroid gland

      • Tx hyperthryroidism

      • Tapazole

    • Radioactive iodine

      • Given IV and concentrates in thyroid tissue to destroy neoplastic cells

      • I-131

      • Special handling and facilities required to handle radioactive waste products


    Review of diabetes

    Review of Diabetes

    • Diabetes Mellitus (Sugar diabetes)

      • Type I

        • Insufficient production of insulin

      • Type II

        • Improper response to insulin

    • Diabetes Insipidus

      • Kidneys are unable to conserve water as they perform their function of filtering blood. The amount of water conserved is controlled by antidiuretic hormone (AKA vasopressin)

    • Insulin

      • Onset

      • Peak

      • Duration of action


    Endocrine and hormonal drugs2

    Endocrine and Hormonal Drugs

    • Regular insulin

      • Shortest acting

        • 1-4 hours IV

        • 4-10 hours SQ

      • Tx of DKA

      • Regular Iletin II

      • Humulin R

      • Novin R


    Endocrine and hormonal drugs3

    Endocrine and Hormonal Drugs

    • NPH inulin/Lente insulin

      • Midrange duration

        • 6-24 hours SQ dog

        • 6-12 hours SQ cat

      • NPH

      • Lente

      • Humulin N

      • Vetsulin


    Endocrine and hormonal drugs4

    Endocrine and Hormonal Drugs

    • Protamine Zinc Insulin/Ultralente

      • Longest acting

      • 8-24 hours SQ

      • Used to be the insulin of choice in cats-no longer!!!

      • Humulin U

      • PZI


    Insulin use

    Insulin Use

    • Store in fridge

    • Don’t freeze

    • Gently roll bottle don’t shake!

      • Insulin molecules are fragile and will deteriorate if handled roughly

    • Use proper syringe

      • U100

      • U40


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