DRUG ACTIONS AND THE BODY Flashcards
drug becomes a solution so that it can
cross the biologic membrane.
PHARMACEUTIC PHASE
Approximately 80% of drugs are taken by
mouth
PHARMACEUTIC PHASE
PHARMACEUTIC PHASE Is also called
Dissolution Phase
Drugs that DON’T HAVE PHARMACEUTIC
PHASE
*SQ
* IM
* IV
3 Phases of Drug Action
- Pharmaceutic
- Pharmacokinetic
- Pharmacodynamics
Breakdown of tablets in smaller particles
DISINTEGRATION
Dissolving of the smaller particles in the GI
fluid before absorption.
DISSOLUTION
Drug in solid form must disintegrate into
small particles to dissolve in liquid.
DISSOLUTION
Process of drug movement to achieve a
drug action.
PHARMACOKINETIC PHASE
Describes how the body handles the
medication
PHARMACOKINETIC PHASE
2 PROCESSES to cross body
membranes
- Diffusion or Passive Movement
- Active Transport Movement
movement of chemical from higher to lower
concentration.
Diffusion or Passive Movement
movement of chemical
against a concentration or electrochemical
gradient.
Active Transport Movement
4 PROCESSES INVOLVED IN
PHARMACOKINETICS
- Absorption
- Distribution
- Metabolism/Biotransformation
- Excretion/Elimination
Movement of drug particles from GI tract to
body fluids
ABSORPTION
this absorption occurs by diffusion thus drug doesn’t require energy to move across a membrane.
Passive absorption
Requires a carrier such as enzyme of
protein to move the drug against a
concentration gradient thus energy is required
Active absorption
Process by which cells carry a drug
across their membrane by engulfing
the drug particle.
Pinocytosis
drug passes to the liver first.
First-Pass/Hepatic First Pass
o Blood flow
o Pain
o Stress
o Hunger
o Fasting
o Food
o pH
FACTORS THAT AFFECT DRUG ABSORPTION
Drug administered through this have the most rapid onset of action
IV
Drug in ________are absorbed faster than tablets of capsules
elixir or syrup formulation
Drug administered in______are absorbed quickly and have more rapid onset of action than those given in opposite
high doses
Subcategory of absorption
BIOAVAILABILITY
percentage of the administered drug
dose that reaches the systematic
circulation
BIOAVAILABILITY
bioavailability of this route occurs after absorption and first pass metabolism
oral route
Percentage of Bioavailability for Oral route
always less than 100%
Percentage of Bioavailability for IV route
100%
Percentage of Bioavailability of Oral drugs that have high first pass hepatic metabolism
20% to 40%.
o Drug form
o Route of administration
o GI mucosa and motility
o Food and other drugs
o Changes in liver metabolism
FACTORS THAT AFFECT BIOAVAILABILITY
caused by
liver dysfunction or inadequate hepatic
blood flow
Changes in liver metabolism
Process by which the drugs become
available to body fluids and body tissues.
DISTRIBUTION
Drugs with a_____of drug distribution have a longer half-life and stays in the body longer
larger volume
Drugs with a_____of drug distribution have a longer half-life and stays in the body longer
larger volume
Heart, liver, kidney, and brain receives the_____blood supply
MOST
Skin, bone, and adipose tissues receive a
_________ blood flow or supply
LOWER
They possess the special anatomical barriers that inhibit many chemicals and medication from entering
Blood – brain barrier and Fetal – placental
barrier
o Blood flow
o Drug’s affinity to the tissue
o Protein binding effect
FACTORS THAT AFFECT DISTRIBUTION
Drugs that are greater than 89% bound to
protein are known as
Diazepam 98%
HIGHLY PROTEIN-BINDING DRUGS
61%-89% bound to protein are
Ex: Erythromycin 70/5
MODERATELY HIGH PROTEIN BOUNDS.
30%-60% drugs bound to protein are
Ex: Aspirin 49%
MODERATELY PROTEIN BOUNDS
Less than 30% drugs bound to protein are
Ex: Amoxicillin 20%
LOW PROTEIN BOUND DRUGS.
This lead to drug toxicity.
Low Serum Albumin Level
Prevent some medication from entering
certain body organs.
BARRIERS TO DRUG DISTRIBUTION
- Blood Brain Barrier
- Placental Barrier
BARRIERS TO DRUG DISTRIBUTION
– to pass this barrier, drug must be lipid soluble and loosely attached to plasma protein
Blood Brain Barrier