Exam Two Flashcards

Pharmacology

scientific study of drug actions and their effects on living organisms

Pharmacokinetics

movement of drugs through the body

the study of what the body does to drugs

how drugs are handled by the body

Pharmacodynamics

study of what the drug does to the body

Factors that Influence Pharmacokinetics

route of administration

absorption

distribution

metabolism

excretion/elimiation

Distribution

passage of drug from bloodstream into organs

Individual Differences that Affect Pharmacokinetics

gender

race/ethnicity/genetics

age

body weight/size/fat content/health/prior experience

Absorption

movement of a drug from the site of administration (external world) into the blood stream

Passive Diffusion

molecules passing through a semipermeable membrane from high concentration to low concentration

Oral Administration

drug is absorbed through the gastrointestinal system

Per Os (P.O.)

Latin for by mouth

seen on doctor’s prescription for oral administration

Small Intestines

where most drugs are absorbed into the blood stream in the G.I. system

lots of surface area and lots of places for drugs to be absorbed

drugs stay in here for a long time

pH in neutral and drugs become unionized

Absorption Rate of Orally Administered Drugs

20-30 minutes to reach brain

75%of lipid soluble psychoactive drugs absorbed in 1-3 hours

total absorption in 6-8 hours

Reasons to Take Drugs With or Without Food

food slows absorption and gastric emptying

buffers G.I. system from drugs that irritate it

some foods deactivate some drugs

some foods influence rate by changing G.I. activity

Advantages of Oral Administration

relatively safe

relatively slow absorption

easy

self-administered

painless

ecominical

Disadvantages of Oral Administration

relatively slow

not soluble and stable in stomach

cannot pass from G.I. track into circulatory system

bad taste, vomiting, stomach distress

highly variable and unpredictable absorption

cannot use in certain situations

First Pass Metabolism

orally administered drugs are metabolized by G.I. and liver enzymes before they reach their target

other routes of administration bypass this

reduces bioavailability

Buspirone

antianxiety drug that has few drug interactions and side effects but only about 5% gets to the brain because an enzyme breaks it down

taking it with grapefruit juice can inhibit the enzyme and allow more to get to the brain

evidence suggests higher effectiveness but also more side effects

Rectal Administration

form of mucous membrane administration

suppository form

used when a person is vomiting, unconscious, unable to swallow, or is an infant

absorption is irregular, unpredictable, and incomplete

relatively slow absorption 

Eye and Ear Administration

a form of mucous membrane administration

typically used for local effects

Administration by Inhalation

absorbed through mucous membranes in lungs

quickest onset and fastest to get drug out (10 sec faster than IV)

Reasons Absorption by Inhalation is so Fast

lungs have large surface area, lots of blood flow, and are specialized for exchange of gas

drug also has less physical space to cover

Forms of Inhalation

gaseous vapor/huffing

smoking

powder inhalation

Advantages of Inhalation

rapid onset and offset

good control of how much is in the body and when

Disadvantages of Inhalation

rapid onset and offset can make it trickier to control

damage to lungs, particularly when smoking

general problems associated with smoking

gas vapors may not be mixed with enough oxygen

smoking generally not a prescribed method

Electronic Cigarettes

battery operated devices designed to deliver nicotine with flavorings and other chemicals to users in vapor instead of smoke

other ingredients not well regulated

usually does not work as a smoking cessation therapy

Sublingual Adminitration

a way of administering through the mucus membranes of the mouth

administered under the tongue

Buccal Administration

a way of administering through the mucus membranes of mouth

administered in the cheek

Intranasal Administration/Snorting

administering drugs through mucus lining of nose

avoids G.I. track and may bypass blood brain barrier

Transdermal/Topical Administration

across the skin in the form of creams or patches

especially for lipid soluble drugs

controlled, sustained delivery at a programmed rate

avoids first pass metabolism

potential for skin irritation

Sites for Injection of Drugs

veins

muscles

under skin

brain (rare)