Pharmacology Flashcards
Pharmacokinetics
What the body does to drugs or how the drug moves within the body
Therapeutic Index
Relationship between a drug’s ability to achieve the desired effect compared to its tendency to produce toxic effects
How is the therapeutic index expressed
Ratio between lethal dose (LD50) and dose that is effective (ED50)
What does a high therapeutic index indicate
The drug is safer with higher therapeutic index
Bioavailability
The percentage of the drug that is administered and reaches systemic circulation
First Pass Effect
Orally administered drugs travel to the liver before reaching systemic circulation and may be removed before they are able to take affect
Metabolite
Left over components of a drug after chemical structure has been changed
Pharmacodynamics
What the drug does to the body and how it works
Peak Plasma Level
Maximum concentration reached in the body
At what point is the elimination rate equal to the absorption rate
Peak plasma level
How is frequency of dosing determined
Peak plasma level, want to keep plasma drug concentration at effective level
-cidal
Kill organisms
-static
Prevent organism’s replication
Antimicrobial
Kill or inhibit the growth of microorganisms
Classifications of antimicrobials
Aminoglycosides Carbapenems Cephalosporins Lincosamides / Macrolides Penicillins Quinolones Tetracyclines Sulfonamides Antifungals Antivirals
Mechanisms of action for antimicrobials (5)
Disruption of development of cell wall
Damaging cell membrane in static or adult populations
Interference with microbial protein synthesis
Inhibition of nucleic acid production
Disruption of microbial metabolic activity
Mechanism of action for penicillins
Disrupt formation of cell wall and bacteriostatic
Mechanism of action for polymixins
Damage cell membrane in adult populations / changes permeability
Mechanism of action for aminoglycocides
Interfere with protein synthesis and bactericidal
Mechanism of action for tetracyclines, lincosamides, chloramphenicol and macrolides
Interfere with protein synthesis and bacteriostatic
Mechanism of action of antifungals
Inhibit RNA and/or DNA synthesis
Mechanism of action for sulfa drugs
Disrupt metabolic activity / replication
Categories of analgesic & anti-inflammatory drugs (4)
Opiods
NSAIDS
Local Anesthetics
Alpha-2 agonists
What are the most commonly used analgesic drug in vet med
Opioids
Mechanism of action for opioids
Block transduction of the pain impulse in peripheral tissues and dampen modulation and perception
Types of opioid receptors
Mu
Kappa
Delta
Pure agonist opioids
Stimulate all opioid receptors
Examples of pure agonist opioids
Morphine Meperidine Hydromorphone Oxymorphone Methadone Fentanyl Sufentanil Afentanil
Partial agonist opioids
Bind to an opioid receptor, less effective than pure agonists
Examples of partial agonist opioids
Buprenorphine
Agonist and Antagonist opioids
Block one type of receptor while stimulating another
Examples of agonist & antagonist opioids
Butorphanol
Nalbuphine
Pure antagonist opioids
Attach to opioid receptors, but do not activate them
Examples of pure antagonist opioids
Naloxone
Nalmefene
What type of drugs are reversal agents for opiods
Pure antagonist opioids
Mechanism of action of NSAIDs
Block prostaglandin formation by inhibiting COX enzymes
Why do cats not metabolize NSAIDs efficiently
Deficiency in glucuronyl transferase enzymes
How do local anesthetics work
Completely block transmission of nociceptive stimulation, preventing signal from reaching CNS
Mechanism of action of local anesthetics
Bind to receptors in sodium channel and prevent depolarization
Primary action of alpha-2 agonist
Sedation
What type of drug provide sedation with some analgesic properties
Alpha-2 agonists
What type of drug works at all 4 stages of the pain pathway
Alpha-2 agonists
4 Steps in pain pathway
Transduction
Transmission
Modulation
Perception
Effect of blocking NMDA receptor activity
Significantly reduces pain wind up / hypersensitivity
Drug classes effecting CNS
Anticholinergic
Neuromuscular blocking agents
Adrenergic Agents
Anticholinergics
Block action of acetylecholine at muscarinic receptors
Examples of anticholinergics
Atropine
Glycopyrrolate
What is used to treat sinus bradycardia, atrioventricular block and sinus arrest
Atropine
Glycopyrrolate