Exam 1 Terms Flashcards
Topical Route of Drug Administration
Dermal, Intranasal, Mucous Membrane, Eyes
Enteral Route of Drug Administration
Buccal, Sublingual, Oral, Rectal
Parenteral Route of Drug Administration
Intravenous, Intramuscular, Subcutaneous, Transdermal, etc.
Membrane proteins that control the influx of essential nutrients and ions and the efflux of cellular waste, environmental toxins, and drugs.
Transporters
Include Organic Anion Transporting Polypeptides (OATPs), Organic Anion (OATs), and Organic Cation (OCTs) transporters.
SLC (Solute Carrier)
Active transporters that rely on ATP Hydrolysis to actively pump their substrates across membranes.
ABC (ATP Binding Cassette)
Pharmaceutical factors involved in GI absorption via passive diffusion.
Solubility/Concentration, Stability, and Controlled Release Preparations
Chemical properties of drugs involved in GI absorption via passive diffusion.
Molecular Size, Lipid Solubility, and Ionization Coefficient (pKa)
Drugs that cross membranes by passive diffusion tend to accumulate in compartments where the degree of ionization is the greatest.
Ion Trapping
Relates the amount of drug in the body to the concentration of drug in the vascular compartment.
Volume of Distribution (Vd)
Normal Vd in the vascular compartment.
3-5 L
Normal Vd in the extracellular compartment.
10-20 L
Normal Vd in the total body water compartment.
35-50 L
Important plasma proteins for drug binding.
Albumin (acidic drugs), Alpha1 Acid Glycoprotein (basic drugs), Lipoproteins, Specific hormone carrier proteins
Consequences of drug binding to plasma proteins.
Reduces the concentration of unbound drug, may slow the distribution and elimination of the drug (depot), and represents a potential site of drug interaction.
There is an increased risk of an adverse drug reaction (ADR) with:
Increased protein binding, decreased Vd, and decreased elimination kinetics.
Reaction that results in relatively minor chemical modification of the parent compound.
Phase I Reaction; metabolite more polar
These reactions are conjugations.
Phase II Reaction; metabolites are pharmacologically inactive
Enzyme located in liver and several other organs that oxidatively metabolizes most drugs.
Cytochrome-P450; localized in the sER; dependent on NADPH and molecular O2; low degree of specificity
Quantitatively most important phase II reaction.
Glucuronidation
Type of drugs that can be secreted by the liver into the bile (Biliary-fecal route).
Amphipathic, lipid-soluble conjugated metabolites, with a MW > 300
Enterohepatic Cycle
- Active drug or metabolite can be excreted in the feces
- Drugs can be secreted and subsequently reabsorbed
- Metabolites can be secreted and then reconverted to the active drug in the intestinal lumen by bacterial enzymes and reabsorbed (e.g. oral contraceptives)
Renal Clearance
Cl = (U x V) / P
Intrinsic ability of the liver to eliminate a drug in the absence of limitations imposed by blood flow.
Intrinsic Clearance
Orally administered drugs must pass through the liver before gaining access to the systemic circulation.
First Pass Effect
Cl = 0
Drug filtered and completely reabsorbed
Cl = ~120 ml/min
Drug filtered and not reabsorbed
Cl = ~650 ml/min
Drug filtered and maximally secreted
The study of the time course of drug concentration in the body, usually as reflected in the plasma concentration.
Pharmacokinetics
Characterized by a constant fractional change per unit time.
First order kinetics (exponential kinetics); rate constant (ke)
Characterized by a constant amount of change per unit time.
Zero order kinetics (saturation kinetics)
The time required for 50% of the drug remaining in the body to be eliminated.
Half-life (t1/2); for first order kinetics
The volume of biological fluid such as blood or plasma that would have to be completely freed of drug to account for the rate of elimination.
Clearance; expressed in volume per unit
One Compartment Model
- Body is a single compartment
- Distribution of drugs is uniform and rapid
- Elimination of drugs conforms to first order kinetics
Two Compartment Model
- Body contains two compartments
- All kinetics are first order
- Elimination is from the central compartment
When a drug is administered intravenously, the plasma concentration will increase until the rate of elimination and administration are equal.
Plateau Principle
Steady-State Concentration
Css = dosing rate / Cl
Number of half-lives required to reach steady state.
4-6
The amount of drug required to achieve a given steady-state value in plasma is the amount that must be in the body when the desired steady-state is reached.
Loading Dose
This remains relatively unaltered in elderly patients.
Absorption
This is slower on average in elderly patients.
Hepatic Metabolism
This decreases in general with elderly patients.
Glomerular Filtration Rate
The study of the biochemical and physiological effects of drugs and their mechanism of action, including the relationship between the dose (or concentration) of a drug and the effect it produces.
Pharmacodynamics
Drugs that mimic the effects of endogenous ligands by interaction with the same receptors.
Agonists
Compounds that inhibit the response of a specific agonist by competition for binding sites.
Antagonist
D + R (D-R) –> E
Occupation Theory
A maximal effect can be produced by a drug when only a small proportion of receptor is occupied.
Spare-Receptor Concept
The maximum effect of a drug.
Efficacy; refers to the stimulus properties of the drug receptor complex
A comparative measure that refers to the different doses of two drugs that are needed to produce the same effect.
Potency
A drug that will generate a response that is less than maximal.
Partial Agonist
The dose causing an effect that is 50% of the maximum or a response in 50% of the population.
ED-50
The dose that is lethal (or toxic) for 50% of the population.
LD-50
Therapeutic Index
LD-50 / ED-50
Drugs that stabilize normally active receptors in an inactive conformation.
Inverse Agonist
A condition in which increasing doses of a drug are required to generate the same effect.
Tolerance
Acute tolerance (i.e. within minutes to hours)
Tachyphylaxis
The effect of genetic variation on drug response.
Pharmacogenetics
The application of genomics to the study of human variability in drug response and development of new drugs.
Pharmacogenomics
The observed characteristic of a drug (e.g. clearance or rate of metabolism).
Phenotype
A variation in the DNA sequence that is present at an allele frequency of >1% of the population.
Polymorphism
Has two defective alleles and lacks functional enzymes.
Poor Metabolizer
Heterozygous for one functional allele; has two partially defective alleles that cause reduced metabolism.
Intermediate Metabolizer
Two normal alleles.
Efficient/Extensive Metabolizer
Duplicated or multiduplicated functional alleles.
Ultra-Rapid Metabolizer
Major mediator of inflammation, anaphylaxis, and gastric acid secretion.
Histamine
Predominant storage site for histamine in most tissues.
Mast cells and Basophils (in blood)
H1 Histamine Receptor effects
Vascular and Extravascular smooth muscle, endothelial cells, glands, CNS; most abundant receptor
H2 Histamine Receptor effects
Gastric parietal cells, cardiac muscle
Triple Response
Histamine released intradermally; 1. localized red spot, 2. brighter red flush (flare), 3. a wheal that is discernible in 1-2 mins
15 steps to reduce risk of hospital infection
- Clean hands
- Clean stethoscope
- Antibiotic catheter
- Choose low infection rate surgeon
- Prepare for surgery by showering with chlorhexidine soap (get rid of skin bugs)
- Get tested for MRSA
- Stop smoking
- Remind doc that antibiotic may be needed before first incision
- Ask doc about keeping patient warm during surgery
- Use clippers rather than a razor for surgical site
- Avoid touching hands to mouth, don’t leave food or utensils on bed sheets
- Monitor glucose constantly
- Avoid UT catheter if possible, remove ASAP if used
- Make sure IV is clean and changed every 3-4 days
- Follow this during Cesarean surgery
Ascariasis
- Caused by intestinal nematode
- Acquired by ingesting contaminated vegetables and drinking-water
- Most prevalent helminthes infection in the world