• 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: ________

     

     

     

                                                   ANTIBIOTICS 

     

     

    XXXXXXXX

     

    History

    Components

    Forms

    Effective 

     

    1. Penicllins 

     

     

     

     

     

     

     

     

    2. Amino-

         Glycosides

     

     

     

     

     

     

     

    3. Cephalo-

       Sporins

    \

     

     

     

     

     

     

    4. Quinolones

     

     

     

     

     

     

     

     

    5. Chloram-

     

        phenicol  

     

     

     

     

     

     

    6. Tetra-

     

       cyclines

     

     

     

     

     

     

       

    **Erythromycin 

     

     

    **Azithromycin                                    

     

     
    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 

        -medication

     

    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

                system    

     

         -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 

     

    ANTHELMINTICS (de-wormers) -IMPORTANT 

        -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

                metabolism

     

                   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

                                                       larvae   

     

                   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

                     parasites     

     

              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

                                                 result 

                                

                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 

     

              TOXICITY SYMPTOMS

     

              -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

                                                  diuretic 

     

                   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

                                                                                                                (neuro-transmitters

     

                       ACh is a neurotransmitter

     

     

     

    I. AUTONOMIC DRUGS- 

     

     

         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 

                       Short-acting 

     

              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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