pharm & tox - ch 4/5

solvent

thing that dissolves the ingredient

solute

the material you want to add to make the solution

ratio concentration

expresses the concentration of a drug as a proportion of solute to solvent or total solution

saturated solution

refers to having the maximum amount of solute possible in a given solvent; can vary based on temperature & fluid pressure

solution

does not separate out

suspension

needs to be mixed every time it is used

diluent

liquid we dissolve the vaccine material into

constant rate infusion (CRI)

consists of a calculated volume of medication at a specific concentration to be delivered over a period of time

peak level

when medication is at its highest concentration within the body

trough level

when medication is at its lowest concentration within the body

liquid nutrition

used for patients who cannot tolerate bolus feedings

total parental nutrition (TPN)

nutrition given directly into the vein

sensible loss

measurable

insensible loss

not measureable

the biggest contribution of water in animals is from…

intracellular fluid

what percentage of an animal’s fluid content is water?

60%

what percentage of a neonate’s fluid content is water?

80%

when checking for dehydration, subjective things to check for include…

skin turgor, mm status, sunken eyes, water intake & urine output/color, tachycardia

when checking for dehydration, objective things to check for include…

packed cell volume, plasma protein (total solids), urine specific gravity, anemia

hypovolemia

loss of intravascular fluids

dehydration

refers to other forms of fluid loss (not including IV)

what is the maintenance fluid rate for dogs?

60ml/kg/day

what is the maintenance fluid rate for cats?

40ml/kg/day

osmolality

refers to the ability of a fluid to “pull in” water

crystalloids

most commonly used solution; classified as hypotonic, isotonic, & hypertonic

isotonic crystalloids

when sodium content & osmolality are close to that of the extracellular fluid (ECF)

hypotonic crystalloids

sodium & osmolality are less than that of the ECF; pulls fluid out of the vasculature strongly

hypertonic crystalloids

osmolality is greater than the ECF; pulls fluid into the intravascular space from the ECF & even intracellular space

colloids

solution used when crystalloids are not working; large molecular weight means they cannot get into cells & stay in vascular system for longer; expand plasma volume by pulling fluid from interstitial space

natural colloids include…

albumin, fresh frozen plasma (FFP), frozen plasma (FP), whole blood

synthetic colloids include…

vetstarch, hetastarch, turbostarch

vetstarch

has a smaller molecular weight & can be given at a higher rate than hetastarch

hetastarch

hydroxyethyl starch

coagulopathy

affects coagulation by prolonging partial thromboplastin, prothrombin, & bleeding times

type III hypersensivity reaction

abnormal immune response that is mediated by the formation of antigen-antibody aggregates called immune complexes — these aggregates can precipitate in various tissues throughout the body

fresh frozen plasma (FFP)

contains all viable factors

frozen plasma (FP)

when FFP is thawed & refrozen; does not contain factor V or VIII when frozen

whole blood

contains all components of blood

what clotting factors does FP contain?

2, 7, 9, 10

when is whole blood given?

when patients suffer from blood loss anemia

what cannot be in a line or flushed during a blood transfusion?

lactated ringers because of their calcium content

what can occur is a patient is receiving multiple transfusions within a short period of time?

hypocalcemia

what needs to be added to stored blood to keep it from clotting?

anticoagulants

what are issues with hetastarch?

volume overload, coagulopathy, hypersensitivity reactions, etc.

human albumin can be given to dogs, but only…

once in their lifetime

when are colloids typically used?

hypovalemia that is not from dehydration, hypoalbuminemia, edema, head trauma, & septic shock

hypertonic saline

hyperosmotic but does not cross the BBB; draws water from the brain reducing intracranial pressure as well as decrease blood viscosity to enhance cerebral blood flow & oxygenation

when are isotonic crystalloids used?

v/d, pancreatitis, shock, IBD

when are hypotonic crystalloids used?

when there is a problem with sodium retention, or in diabetic keto acidosis (DKA)

when are hypertonic crystalloids used?

hypovolemia, sometimes for intracranial edema relief, and in very large dogs where isotonic fluids cannot be given quickly enough to achieve desaired effect

why should you use caution when using isotonic crystalloids on a patient with renal &/or cardiac disease?

sodium can compromise their functions

hypertonic crystalloids should be used with caution because they are extremely…

dehydrating

what are the 4 steps of the pain pathway?

transduction, transmission, modulation, perception

transduction

conversion of noxious stimuli (chemical, thermal, mechanical energy) into an electrical impulse

transmission

stimulated receptor travels to a sensory nerve carrying it to the spinal cord — nerve blocking bundles of sensory nerves clock this process & information travels from the point of stimuli to the CNS

modulation

transmission of the wave up the spinal cord to the brain — body produces neurotransmitters that can dampen the sensory signal

what does epidural do?

blocks modulation

perception

recognition of pain impulse at the conscious level happens in the brain — when the impulse reaches the higher level of the brain, the animal feels pain

what does pain progress from & to?

initial acute, focal pain → diffuse, throbbing pain

hyperalgesia

makes pain receptors in adjacent areas more sensitive to any potentially painful stimuli

hyperesthesia

increasing sensitivity to any stimuli; very reactive

what is the windup phenomenon a combination of?

hyperalgesia & allodynia

allodynia

pain due to a stimulus that does not normally provoke pain; heightened sense of pain

windup phenomenon

process of increasing success in transmitting pain up the spinal cord; increase in pain intensity over time

windup can occur even when the patient is…

unconscious

what is the most potent pain-relieving drug used in vet med?

opioids

analgesics

class of drugs that help relieve the body from the sensation of pain

what are the types of opioid receptors?

mu, kappa, delta

what class of drugs are opioids in?

analgesics

endogenous

produced by the body in response to a stimulus

exogenous

introduced to the body via enteral or parenteral routes

what is the natural form (opium derivative) of exogenous drugs?

morphine

what are 2 types of opioids

endogenous & exogenous

steps to exogenous opioid administration

absorption, distribution, metabolism, excretion

absorption

movement of drugs from the site of administration to the bloodstream

distribution

movement of administered drugs through body compartments

metabolism

biotransformation of drug to be able to be eliminated from the body

excretion

irreversible removal of drugs from the body

first pass metabolism

drugs metabolized by the liver prior to reaching systemic circulation

cytochrome p450 enzymes

phase 1 → acts to make drugs more water soluble & creates active metabolites

phase 2 → convert inactive metabolites ready for excretion

glomerular filter rate (GFR)

measures how much blood your kidneys clean per minute through glomeruli (low = slow excretion, high = fast excretion)

what is first order kinetics dependent on?

plasma concentration

what is zero order kinetics dependent on?

constant rate of excretion

uses of opiods

pain treatment, can be given before a painful procedure to reduce windup, can be used along with anesthetic agents

what is the strongest opioid receptor?

mu receptor

where are mu receptors found?

on nerves in the pain pathway of brain & spinal cord

what do most full mu agonists stimulate?

kappa receptors (enhances analgesic effect)

what is the antagonist used to reverse the effect of opioids?

naloxone

what is the antagonist used to reverse the effect of benzodiazepines?

flumazenil

what is the antagonist used to reverse the effect of xylazine?

yohimbine

what is the antagonist used to reverse the effect of dexmedetomidine?

antisedan

how does mu mediated analgesia work?

decreases neurotransmitters, dampens excitation at synapses

what happens when neurotransmitters are blocked/significantly decreased?

pain is decreased significantly

what are the risks of using a pure mu agonist

respiratory, cardiac, & GI effects

what respiratory effects can occur when using a pure mu agonist?

suppresses coughing (reduction of respiratory refluxes), respiratory depression (leads to respiratory arrest & cardiac arrest)

what GI effects can occur when using a pure mu agonist?

decreased GI secretions & intestinal movement

miosis

pupil constriciton

mydriasis

pupil dilation

when given a mu agonist, miosis will occur in…

dogs

when given a mu agonist, mydriasis will occur in…

cats