• Level 3 Pharmacology-CH25-Antimicrobials/Antibiotics

    CH 25- Pharmacology Notes - Antimicrobial Agents   (Antibiotics) pp. 834-838 


    A. Antimicrobial Agents 


         -antibiotics initially produced by microorganisms, which destroy OR

           inhibit growth of other microorganisms 


         -kill life-threatening infections 


         Can be produced chemically 


    B. Antibiotics Specific 


         -each antibiotic effective against specific groups of microorganisms

         -some are BACTERICIDAL: destroy bacteria 

         -some are BATERIOSTATIC: inhibit bacteria growth

         **some antibiotics are BOTH bactericidal AND bacteriostatic 


         -species of bacteria affected by antibiotic= SPECTRUM 

         (broad spectrum antibiotics are effective against a wide range of microorganisms) 

          G+ and G-


    C. Classifying Bacteria- Gram Stain 


         -ability of bacteria to absorb dye (Gentian violet) into the cell wall 


         -GRAM stain results: 


          G+   (absorb dye-dark blue cell walls) 

          G-    (do NOT absorb dye-light pink cell walls) 


    D. Effective Antibiotic 


         -must be able to reach site of infection 

         -concentration must be maintained over period of time to destroy ALL bacteria OR

           inhibit bacterial growth so natural defenses can take over 

         **Length of antibiotic therapy depends UPON: the microorganism (pathogen),

             site of infection, duration of infection 


          -Minimum length of antibiotic therapy is usually 5 days 

         -stopping an antibiotic too soon may cause under-exposed pathogens to become

          resistant to the antibiotic 


         **Nosocomial antibiotics are antibiotics which originate in a clinical setting 



    E. Choices of Antibiotic Treatment   


         -BEST: culture bacteria (grow on petri dish, then test several antibiotic discs) 

                       **if bare space occurs-bacteria sensitive to antibiotic patch(disc) 


        -HOWEVER: sometimes time/money a concern-treat with antibiotic which seems the 

          BEST: Empiric Treatment


    **WHEN selecting an antibiotic, one should, chose an antibiotic which destroy/inhibit the pathogen BUT NOT DISTURB the normal bacterial flora (good bacteria in body) 


    WHY would you not want to harm the normal-existing flora of bacteria? 


    CAREFUL: Over-use of potent broad-spectrum antibiotics can lead to resistant strains of bacteria 
































    Name: _______________________                                      Date: ________














    1. Penicllins 









    2. Amino-









    3. Cephalo-









    4. Quinolones









    5. Chloram-









    6. Tetra-















    Comments (-1)
  • Disease Prevention-CH 15-Level 2 (10th)

    NOTES: CH 15 DISEASE PREVENTION –pp. 242-244



    A. Animals resistant to disease because of:   


        - immunity

        -good nutrition

        -skin/mucous membranes protect from invading pathogens

        - normal bacteria flora-inhibit growth of other organisms

        -adhesion sites-pathogen must adhere to animal’s cells before infection begins


    B. How to maintain normal bacteria flora: 


        -reduce stress (see below) 

        -proper nutrition 



    C. Stress in animals


         -stress considered a threat/animal (animal increases epinephrine and cortisol production)


         **cortisol can help animal in stress ( increases carbohydrate metabolism, more glucose to brain, reduces inflammation to damaged tissue) 


         ***adverse effect of cortisol- weakens immune system, increases risk of diabetes, muscle weakness) /Cushing’s Disease-(hyperadrenocorticism) = CHRONIC elevated cortisol levels



         -stress increases activity of sympathetic nervous system


         D. Nutrition and Stress


        -nutrition maintains immune system  

              Vitamins (ex. Vitamin E) and minerals (ex. selenium) keep immune system strong

              Antioxidants (oxidation-inhibiting vitamins/minerals0 play role in healthy immune



         -sudden changes in diet: (decrease normal flora in intestinal tract)

                                                    allows for pathogen invasion


              **flora = good bacteria                pathogen = bad(disease-causing bacteria) 


               **antibiotics can decrease normal flora-CAREFUL 


                                                                                                                                    p. 2 


    E. Other forms of stress in animals


        -over-crowding: increases competition for food and comfort, animals too close

                                                                                                           (spread diseases) 


        -increased urine/feces contaminate animal’s environment 

        -humidity higher in crowded areas/allows pathogens to survive outside body 


         **VENTILATION: air exchanged from inside of building to outside 


               Without ventilation- animals exhale (add heat, moisture, pathogens to air) 

                                              Ammonia/hydrogen sulfide released from urine/feces 


              **the above irritate mucous membranes of animals, LOWER respiratory tract defense systems/easier for pathogens to invade respiratory tract 


         ALSO: without ventilation-animals stir up dust which carries pathogens and irritates respiratory tract 



    F. HOW to prevent Disease- FRESH AIR 


         -bring fresh air from outside INTO inside barn area; reduce moisture, dust, etc. 


         VENTILATION methods:  


         1. some barns built for natural air flow (IN/OUT) 

         2. some barns use fans to move air/keep clean

         3. some barns, fans on ONE end of barn, air outlets on OPPOSITE end = TUNNEL VENTILATION (a breeze of 3-5 miles/hour can be created) 


    **PROBLEM- in cold weather, less air exchange can take place (heat issues) BUT..


         At least 4 air exchanges per hour should STILL take place 

         In summer, up to 30 air exchanges may be necessary 


    G. OTHER

         -older animals, have a higher level of immunity than the young (WHY?) BUT..

              older animals could be carriers for pathogens-THEREFORE: 


         **IDEAL air flow in barns should flow from the youngest to the oldest-

             (young animals not exposed to possible pathogens exhaled by older animals)

         **ALSO: young animals should not mingle with older animals 

                          -keep all bedding clean/dry-this keeps animal’s fur clean/dry/
    Comments (-1)
  • Level 3-Pharmacology Addendum (Anthelmentics)

    Pharmacology- CH 25- Addendum Notes


    Treatment of Internal Parasites 



        -parasites SHORTEN life span of animal 

        -parasites REDUCE quality of life for host 


    **Current anthelmintics eradicate the parasite and are less toxic to host

         Also more convenient to give since come in chewable and paste forms


    Some types of Anthelmintics: 


         A. Benzimidazoles- large class of anthelmintics which interfere with parasite



                   1. Albendazole- fights liver flukes (flatworm in liver) 


                   2. Fenbendazole/Mebendazole- used in small animals to eradicate

                        roundworms, hookworms, whip worms and SOME tapeworms


         **NOTE-Adverse effects (toxicity) not usually seen at recommended dosages


         B. Organophosphates- affect neurotransmitters (ACh ) of parasites 

               (Ex. Trichlorfon)-can be dangerous to humans 


              Signs of toxicity- salivation, breathing difficulties, vomiting, muscle effects

              Treatment: Atropine 


         C. Tetrahydropyrimidines: effective against adult nematodes, not effective against



                   1. Morantel- used in sheep and cattle (feed additive) 


                   2. Pyrantel- horses: pinworms, strongyls, ascarids(round worms) 

                                        Dogs:   hookworms, ascarids 


                    **NOTE: Safe and non-toxic at recommended doses 


         D. Imidazothiazoles- used in most species to treat parasites (equine as well) 

                                             Product packaged as (Drontal Plus, Bayer)  


         E. Milbemycins- paralyze parasites-

                   1. Moxidectin- oral dewormer/boticide for horses

                   2. Doramectin- injectable drug /treats roundworms and arthropod parasites

                                             in cattle and swine   

                                                                                                                                     p. 2 



         F. **Ivermectins- paralyze nematodes by blocking motor neuron transmission 


                   -used in a number of animal species against a wide variety of internal/external



              Cattle, swine, sheep, goats: injectable ivermectin treats roundworms,

                                                           lungworms, cattle grubs, sucking lice, mites


                                                           paste/oral liquid forms treat strongyls,

                                                           pinworms, bots


               Dogs/cats-mainly used to prevent heartworm, but higher dosages used to treat

                Scabies(skin mites) 


         **CAREFUL- Pure-bred collies tend to be sensitive to ivermectin, therefore, careful

                                  dosages must be used


              Over dose symptoms-blindness, ataxia, death 


    ****Heartworm Treatment**** 


              AVMA recommends the following treatment strategy: 

                       -eliminate adult heartworms first (in heart tissue) THEN 

                       -eliminate microfilaria (immature heartworm which migrate) 

                       -before starting HW preventive, a dog must be free of adult and microfilaria 


              Treatment: melarsomine dihydrochloride (arsenic agent)

                                 given by deep IM injection 


               CAREFUL: cage rest required to risk of blood clots (esp. in lungs)

                                    Severe reactions may occur: abdominal bleeding,

                                                                                  hematuria, tachypnea,

                                                                                  icterus(yellowing of skin) 


    ****Heartworm Prevention**** 

         Ivermectin/Milbemycin-given ONCE a month/if more than 45 days between treatments, RETEST for Heartworm    


          1. Milbemycin- (Interceptor by Novartis)        2. Ivermectin/Pyrantel (Heartgard Plus)

                                                                                             by Merial –fights hookworms too


          3. Moxidectin (ProHeart, Fort Dodge)

               paralyzes adult heartworm/larvae in dogs 6 months or older/injectable-last 6 mos

    Comments (-1)
  • Level 3-Pharmacology Addendum (Cardiac Drugs)

    NOTES- CH 25- Pharmacology- Addendum: pp. 829-831 



    I. Diuretic and Cardiovascular Drugs 

         -prevent reabsorption of sodium (Na) and Water

         -increase urine output and sodium excretion 


    A. Diuretics- relieve fluid in tissue (edema) 

                            used for kidney, heart, liver diseases


              1. Furosemide (Lasix)- prevents sodium (Na) and chloride (Cl) to reabsorb

                                                     back into the kidney 


                                  Effect: rapid, produces loss of fluid (diuresis) within 5 minutes

                                               of IV injection   

                                  Forms: oral, injectable 


                       **CAREFUL: lowers potassium (K) levels in blood serum- MONITOR 


              2. Mannitol-produces diuresis 

                                  Form: injectable 


                       **CAREFUL: produces crystals in bottle, dissolve crystals before

                                                administering-warm water bath



     B. Cardiac Glycosides- most potent, hazardous, used to treat heart disorders 


                        **CAREFUL-calculate, administer, observe patient OR death could



                1. Digoxin-used to treat chronic heart failure (CHF) -esp. dogs and cats 

                               Form: oral, tablet, liquid, injectable 

                               Effect: reduces heart’s demand for energy/oxygen 


                        **CAREFUL- over dose can be toxic, especially to those with existing

                                                 liver/kidney problems  

                           symptoms of overdose: vomiting, diarrhea, loss of appetite, depression









                                                                                                                                     p. 2


        C. Antiarrhythmia Drugs


                   1. Quinidine- used to treat arrhythmias in horse/large dogs 


                   2. Lidocaine-used as a local anesthetic, can treat ventricular tachyarrhythmias


         **CAREFUL- ALL antiarrthymia drugs are toxic to heart 




              -horses: anorexia, colic, diarrhea, edema of nasal mucosa, dyspnea, laminitis 


              -dogs: vomiting, depression, lack of coordination, convulsions 


          ***NOTE: Lidocaine if given IV in large dosages, drops blood pressure 



       D.  Angiotensin Converting Enzyme Inhibitors (ACE) drugs 


              -vasodilators (enlarge blood vessels) 

              -primarily used to treat canine CHF 


                   1. Hydralazine- used to treat CHF in small animals (esp. mitral valve) 

                          **side-effect: sodium/water retention-SHOULD be given with a



                   2. Pimobendan- new drug on market to treat CHF 


    Comments (-1)
  • Level 3-Pharmacology-Addendum(Neuropharmacology)

    Neuropharmacology -Addendum



    Overview: CNS includes brain and spinal cord

                       CNS divided into: 

                                                    Autonomic Nervous System- (involuntary) 

                                                    Somatic (motor) Nervous System (voluntary)    


                       Neurons relay information from CNS to rest of body using NT’s



                       ACh is a neurotransmitter







         A. Cholinomimetic Agents: (mimic ACh)   


               1. Bethanechol- smooth muscle stimulant (ex. stomach, intestines, bladder) 


                    -side affects: vomiting, diarrhea, salivation, anorexia 


                     -over-dose: arrhythmias, hypertension, asthma 


               2. Cholinesterase inhibitors-prevent ACh from breaking down, -exaggerated

                     (used mostly to treat internal/external parasites) OR restore rumen/GI tract

                       back to normal after surgery)


                     -over-dose: nausea, vomiting, diarrhea, salivation, sweating,

                                         increased bronchial secretions, bronchospasms,

                                         cardiac arrest, muscle cramps, weakness 



         B. Anticholinergics; (inhibit/stop action of ACh) 


               1. Atropine- derived from belladonna plant, stop ACh


                    -effects: decrease salivation/bronchial secretions (low doses) 

                                   Decrease movement in GI/urinary tract (high doses)


                    **used to dilate (open) eye pupil 

                        used to treat poisoning from insecticides/parasiticides/mushrooms



     C. Neuromuscular Blockers/NMB’s: (paralyze skeletal muscle) 


              1. Vecuronium/Atracurium- newer  


                   -effects: relax skeletal muscles, used with surgical anesthesia 

                   -overdose: respiratory paralysis 


    D. Sympathomimetics: (affect sympathetic nervous system = heart rate, blood pressure,

                                              bronchial airways) 


              1. Epinepherine- (released from adrenal gland when stressed) –FIGHT or FLIGHT 


                   -effect(treats): allergic reactions, bronchospasms, cardiac issues


                   **not available in oral forms-destroyed by stomach acid 



              2. Isoproterenol- used as bronchodilator, cardiac stimulant 


    E. Phenothiazines:   (used as sedatives/tranquilizers) 


              1. Acepromazine- (takes “the edge off”) 


                  -used to prolong effects of anesthesia, reduces anxiety/motion sickness 

                   **prolonged use may promote seizures in dogs 


    F. Others


               1. Xylazine-used widely in horses/cattle-sedative and analgesic


                    **CAREFUL: Causes muscle tremors, respiratory changes in horses  

                                              Cattle extremely sensitive-require 1/10 dosage used in horses 


                    In dogs/cats-causes immediate vomiting 


               2. Propofol- used to introduce anesthesia, (5-10 minutes-metabolized quickly) 


                  **CAREFUL: weakens muscular contractions, esp. respiratory actions 


    G.     Steroids: (extremely active, effect all organ systems) 


                  -used to treat inflammation/auto-immune diseases


                  **LONG-TERM EFFECTS: GI bleeding, infection risk, inability

                       for wounds to heal, irregular heartbeat, muscle cramps, behavioral

                       changes (EX: Prednisolone, Dexamethasone)

         H. Non-Steroidal Anti-inflammatory Drugs (NSAIDs) -less side affects 


               1. Phenylbutazone- original NSAID, used more in horses 


                    **CAREFUL: dogs metabolize drug quickly, difficult to keep in system

                                              cats metabolize drug slowly, can become TOXIC 


              2. Carprofen- approved to use in dogs with arthritis (relieve pain/inflammation)


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