Chapter 2: Drugs and the Body Flashcards
Adverse effects
drug effects that are not the desired therapeutic effects; may be unpleasant or even dangerous.
Brand name
The name given to the drug by the pharmaceutical company, also called a trade name.
Chemical name
Name that reflects the chemical structure of a drug
Generic name
the original designation given to a drug when the company that developed it applies for the approval process.
Orphan drugs
drugs that have been discovered but would not be profitable for a drug company to develop; usually drugs that would treat only a small number of people; these orphans can be adopted by other drug companies to be developed.
Over- the- counter (OTC) drugs
drugs that are available without a prescription for self-treatment of a variety of complaints; deemed to be safe when used as directed.
Pharmacotherapeutics
clinical pharmacology- the branch of pharmacology that deals with drugs, chemicals that are used in medicinal treatment, prevention, and treatment of a disease in humans.
Phase I study
A pilot study of a potential drug, done with a small number of selected, healthy human volunteers.
Phase II study
A clinical study of a proposed drug by selected physicians using actual patients who have the disorder the drug is designed to treat; the patients must provide informed consent.
Phase III study
use of a proposed drug on a wide scale in the clinical setting with patients who have the disease the drug is designed to treat.
Phase IV study
continual evaluation of a drug after it is released for marketing.
preclinical trials
Initial trial of a chemical thought to have therapeutic potential; uses laboratory animals, not human subjects.
teratogenic
Having adverse effects on a fetus.
Pharmacokinetic phase
The process of drug movement to achieve drug action.
- Absorbtion
- Distribution (passive/active transport)
- Metabolism
- Excretion/elimination
Factors affecting absorption
- lipid or water soluble (ie. blood brain barrier)
- Blood flow
- Temperature
- Food, hunger, fasting
- Stress (vasoconstriction)
- Pain
- pH
- Route of administration
- First pass effect (hepatic first pass)
- Bioavailability (how much of the drug actually reaches systemic circulation)
Bioavailability
percentage of administered drug that reaches the systemic circulation. The rate at which the drug is absorbed affects the bioavailability.
- Rapid absorption = more bioavailability
- Slow absorption = less bioavailability
- IV administration = 100% bioavailability
Distribution
Process by which the drug becomes available to body fluids and tissues.
Free drugs
Drugs circulating in the bloodstream
Factors affecting distribution
- Protein binding percentage
- Plasma protein and albumin levels
- Liver disease
- Kidney disease (toxins stay in the body longer)
- Malnourished
- Elderly (hypoalbuminemia)
Half life (t1/2)
The time it takes for one-half of the drug concentration to be eliminated. Example: if the half life of a drug is 4 hours, you give the drug every 4 hours.
Creatinine Clearance
lab test to determine kidney function: Normal = 85-135 ml/min.
Pharmacodynamic phase
Study of drug concentration and its effect on the body. Dose-response and maximal efficacy.
- On-set: beginning
- Peak: maximum therapeutic concentration
- Duration: the drug begins to wear off
Agonists
They are drugs that act through receptors by binding to the receptor to produce a response.
Antagonists
They are drugs that act through receptors by binding to the receptor to block or prevent a response. Example: anti-histamine
Categories of drug action
- Stimulant or depressant
- Inhibition or killing of organisms (chemotherapeutics: antibiotics, antivirals, etc.)
- Irritation (example: constipation)
Tachyphylaxis
lots of different drugs; tolerance.
Placebo effect
Mind over matter (unethical)
Therapeutic index
The window of how much of a drug causes a therapeutic effect and how much causes toxicity
Loading dose
An initial higher dose of a medication may be given to overcome a pain threshold, followed by a lower dose for maintenance.
First-pass effect
A phenomenon in which drugs given orally are carried directly to liver after absorption, where they may be largely inactivated by enzymes before they can enter the general circulation. Oral drugs frequently are given in higher doses than drugs given by other routes because of this early breakdown.
Selective toxicity
Property of a chemotherapeutic agent that affects only systems found in foreign cells without affecting healthy human cells. (example: antibiotics)
Competitive vs. non-competitive antagonists
Competitive antagonists occupy the specific receptor site on a cell, blocking it. Non-competitive antagonists prevent the reaction of another chemical with a different receptor site on that cell.
