Infection and Pharmacology

infection

presence and multiplication of a living organism on or within a host, inducing subsequent injury/disease to the host

host

organism capable of supporting the nutritional and physical growth requirements of another organism

infectious disease

disease state due to an infection that invades the host's body and has potential for harm or lethal consequences to the host

colonization

when a microorganism adheres to epithelial tissue surfaces and can reproduce/multiply in that environment

pathogen

microorganism displaying virulence towards a host, usually causing disease

infectivity

the ability of an organism to colonize a host

virulence

the degree to which an organism is pathogenic and able to infect a host

factors influencing virulence

adhesiveness, evasiveness, and invasiveness

how a symbiotic relationship can become an infection

when the microflora is ingested or contaminates an area it does not belong

chain of infection

pathogen, source/reservoir, transmission/port of entry, susceptible host

factors determining a pathogen's ability to overcome a host's defenses

number of pathogenic organisms transmitted, mode of transmission, stability of pathogen outside of host

prions

infectious proteins

viruses

Pieces of genetic material surrounded by a protein capsule

bacteria

single-celled organisms that lack a nucleus; prokaryotes

fungi

Eukaryotic organisms with chitin cell walls.

parasites

Organisms that grow, feed, and shelter on or in another organism

common symptoms of infection

fever, leukocytosis, lethargy, head/body aches

leukocytosis

higher WBC count

stages of infection

incubation, prodromal, acute, convalescent, resolution

pharmacology

science dealing with the effects of drugs on living organisms

toxicology

adverse effects of drugs on living organisms

pharmacotherapeutics

The treatment of pathologic conditions through the use of drugs

pharmacokinetics

how the body acts on the drug

pharmacodynamics

how the drug acts on the body

agent

any drug, biological product, or medical device

drug

any chemical that affects a biological system

medicine

drug used for the treatment or prevention of disease

pharmacologic tool

drug, biological product, natural substance, or other tool used in research to investigate system/tissue function or effects of drugs

stages of pharmacokinetics

absorption, distribution/storage, metabolism, excretion

factors that influence pharmacokinetics

medication errors, patient compliance, physiological/pathological/genetic variables, drug interactions

enteral absorption

absorption by way of moving through the GI tract

examples of enteral absorption

oral, sublingual, buccal, rectal

pros of enteral absorption

convenient

cons of enteral absorption

less predictable dosage, speed of effect, rish of widespread systemic exposure to drug

parenteral absorption

absorption by direct administration to area, bypassing GI tract

examples of parenteral absorption

injections, topical, transdermal, inhalation

pros of parenteral absorption

more predictable dosage reaching target tissue

cons of parenteral absorption

less convenient

pros of oral absorption

maximum convenience

cons of oral absorption

subject to first-pass metabolism, may cause GI irritation

pros of sublingual absorption

bypasses first-pass metabolism, rapid onset

cons of sublingual, buccal, and rectal absorption

drug biochemistry must fit, limited amount/rate of absorption, local irritation

pros of buccal absorption

bypasses first-pass metabolism

pros of rectal absorption

partial bypass of first-pass metabolism, good for when drugs cannot be given orally

first-pass metabolism

drug metabolism that occurs in the intestines and liver during oral absorption of drugs into the systemic circulation

pros of intravenous injection

instantaneous, maximal absorption

cons of intravenous injection

sterility concerns, crucial to get dose accuracy

pros of intramuscular injection

reservoir

cons of intramuscular injection

sterility concerns, local irritation

pros of subcutaneous injection

reservoir, can be given as a liquid or solid pellet

cons of subcutaneous injection

slowest acting injection, limited amount, sterility concerns, local irritation

pros of topical absorption

close delivery to target site, avoids first-pass

cons of topical and transdermal absorption

rate of absorption varies depending on site of application

pros of transdermal absorption

avoids first-pass metabolism

pros of inhalation absorption

close delivery to target site, avoids first-pass, rapid absorption

cons of inhalation absorption

irritation

bioavailability

percentage of active drug that reaches systemic circulation

factors affecting absorption

blood flow, surface area available, contact time, drug concentration

distribution

process by which a drug reversibly leaves the bloodstream and enters the tissue/cells

factors affecting distribution

size of target, blood flow, drug properties, binding/sequestering of drug, anatomic barriers

tissues that store drugs for the longest

fat and muscle

four types of drug metabolism

active to different active form, active to inactive, inactive to active, remains active until excretion

primary location of drug metabolism

liver

primary location of drug excretion

kidneys

clearance

amount of active drug removed from the blood over a given period of time

factors determining clearance

blood flow and organ's ability to extract the drug from the blood

steady state

point of equilibrium where the dose administered equals the amount eliminated

type I receptor

cell surface receptor

type II receptor

located within the cytoplasm

type III receptor

receptor located on the nucleus

drug selectivity

ability of a drug to interact with a specific receptor of target tissue and not with other receptors

affinity

an attraction to

efficacy

effectiveness

agonist drug action

high affinity for a receptor and high efficacy

antagonist drug action

high affinity for a receptor but no efficacy

quantal response

an all-or-none binary biological response

role of receptor occupancy

concept that the intensity of the drug action is related to the number of receptors occupied and the concentration of occupied receptors

threshold dose

lowest dose that produces a desired effect

ceiling dose

the dose above which no further beneficial drug effect will occur

potency

strength of a drug

therapeutic window

the concentration of a drug that has the desired effects without the toxicity/danger to the body

therapeutic index

the difference between the percentage of people having a toxic response and the percentage of people having a beneficial response to a drug