General Toxicology Flashcards
Most common route of exposure?
Oral Route
Dermal - Insecticides, Inhalant- Toxic Gases
Lethal Synthesis
The metabolite is more than the parent compound
Drug Absorption
The transfer of the drug from the site of administration to the circulation
Molecular Size
The smaller the molecular size, the faster its penetration through the pores.
Lipid Solubility
The greater the lipid solubility, the greater the absorption.
Degree of Ionization
The higher the ratio between N/I, the greater the absorption.
Route of Administration
Fastest to Slowest
Sublingual/Inhalation, Intramuscular, SQ, Oral
Sympathetic Stimulation on Blood Flow
Increases to the skeletal muscles
Decreases to the GIT and SQ sites and skin
T/F: The upper part of the SI is the main site of absorption.
True- has an extensive surface area and rich blood supply
Drug Disposition
The study of the movement of drugs in the body across biological membranes from the time of absorption until elimination.
Biological Cell Membranes
- Lipid Bilayer
- Membrane Proteins and Carbohydrates
- Aqueous Pores or Junctions between cells
2 types of Passive Diffusion:
Transmembrane or Paracellular movement
Simple Diffusion
T/F: Transmembrane movement of water is through intercellular aqueous pores.
False. That is Paracellular Movement.
Transmembrane Movement: by passive diffusion through aqueous protein channels or by flow resulting from osmotic or hydrostatic difference across the membrane.
T/F: Most drugs are strong electrolytes.
False.
Most are WEAK electrolytes
Which way does a drug move in Passive Diffusion?
From High to Low Concentration.
T/F: With Active Transport, drugs move from Low to High concentrations.
True. This is a carrier-mediated transport and requires energy.
Primary- directly from ATP
Secondary- stored energy leftover from Primary Active Transport.
Pinocytosis
When the cell engulfs the drug molecules dissolved in water.
Ex. Sequestration of aminoglycoside antibiotics by renal tubular cells.
Drug Distribution
The transport of drugs from the plasma to the tissues (site of action, site of storage, site of biotransformation).
T/F: Acidic drugs bind to acid alpha1-glycoproteins and lipoproteins.
False. Basic Drugs bind to those.
Acidic drugs bind to Albumin.
Some other drugs bind to Globulin.
Plasma Protein Binding
- Reversible
- Prolongs the half-life of the drug
- Bound form is Inactive
- Drugs can compete on the binding sites
Highly Perfused Tissues
Brain, Liver, Kidney, Endocrine Glands
Moderately Perfused Tissues
Muscle, Skin
Poorly Perfused Tissues
Bone, Fat
5 Tissue Barriers
Brain, Eye, Testicles, Placenta, Mammary Gland
