Facts Flashcards
A drug is a chemical substance used for what three purposes?
- Preventing, treating or diagnosing disease
- Preventing pregnancy
- Recreational or other forms of abuse
What term describes what drugs do to the body?
Pharmacodynamics
What term describes what the body does to drugs and how fast it does it?
Pharmacokinetics
What are the first three pharmacokinetic steps?
Administration > Absorption > Distribution
What are the pharmacodynamic steps?
Receptor agonism or antagonism
What are the final three steps of pharmacokinetics?
Redistribution > Metabolism > Excretion
Most drugs are what kind of compounds?
Organic
Where do most drugs originate from?
Natural sources, but are synthesized for commercial purposes
What are the three types of names that most drugs have?
Chemical
Generic (official)
Trade (proprietary)
What are some of the nine possible formulations of drugs?
Tablets, capsules, pills,
pearls, solutions, suspensions,
ointments, tinctures, salves
What are the two routes of enteral administration?
Oral and rectal
What are the seven routes of parenteral administration of drugs?
Sublingual, intramuscular, intravenous,
subcutaneous, intrathecal, topical,
transdermal
What are the three factors that determine drug absorption and distribution?
- Molecular size
- Solubility
- Conditions at site of tissues to be penetrated by drug
In regard to polarity, what form of a drug can readily penetrate cell membranes?
Nonionized. Drugs that are lipid soluble (non-polar) are able to penetrate cell membranes mor rapidly
Why do plasma proteins “help” drugs?
Highly lipid soluble drugs need help dissolving in the aqueous environment of the blood plasma.
What needs to happen to bound drugs (to plasma proteins) to act on receptors?
While bound they are inactive and trapped in the bloodstream. Only “free drugs” (unbound) are distributed across tissues.
Drugs that ACTIVATE receptors are called ___
Agonists
Drugs that BLOCK receptors are called ___
Antagonists
What term describes the dose required to produce minimum response?
Potency
What term describes maximum magnitude of response?
Efficacy
What term describes the difference between toxic and effective dose?
Margin of safety
What term describes the ratio of toxic and effective dose?
Therapeutic index
Where are most receptors that are targeted by drugs?
The external cell membrane
What kind of drug-receptor bonds are most common?
Ionic bonds (reversible)
Are stronger bonds than ionic possible and are they reversible?
Covalent bonds are rare and irreversible
What are the three categories of drug receptor types?
Extracellular membrane spanning receptors
Extracellular molecules
Intracellular molecules
What are the three types of extracellular membrane spanning receptors?
Transmembrane G protein coupled receptors
Transmembrane enzyme activating receptors
Channel modulators
What is the one type of extracellular molecule receptor?
Enzyme modulators
What are the two types of intracellular molecule receptors?
Genetic transcription modulators
Enzyme modulators
What are the three ways in which drug actions are terminated?
Redistribution
Metabolism
Excretion
What are the two phases of metabolism?
Phase 1: oxidation and reduction to produce more polar metabolites.
Phase 2: conjugation produces a larger metabolite
Kidneys are the major organ of drug excretion. What are the four ways they do this?
Drugs may be:
- filtered in the glomerulus
- secreted from the bloodstream into the nephron
- reabsorbed from the nephron into the bloodstream, and
- excreted into the urine
What is meant by “first pass metabolism”?
The drug is absorbed in the GI tract and passes via the portal vein into the liver where some drugs are metabolized. Sometimes the result is that only a proportion of the drug reaches the circulation.
What is meant by the “enterohepatic cycle”?
Some substances circulate from the liver to the bile, which is excreted into the small intestine where enterocytes absorb it and take it back to the liver.
What is the basic function of the cytochrome P450 cycle?
It permits the transfer of electrons from electron donor compounds to drugs and other metabolic substrates. The result is usually a more polar and excretable metabolite.
