Pharmacokinetics (reduced)

absorption

the process by which a drug moves from the site of administration into the bloodstream

bioavailability

fraction of the original dose the reaches the bloodstream and is available to act on

exercise and absorption

reduces blood flow to the GI tract, slowing absorption of oral drugs

Best practice foe drugs and exercise

take 30 minutes before exercise for optimal effectiveness

active transport

moves against the concentration gradient (low to high)

requires energy

distribution

after absorption the drug is transported through the bloodstream to its site of action

factors influencing distribution

lipid solubility: lipid soluble drugs cross the membrane easily and can accumulate in fat or reach the brain

protein binding: only unbound drug is active

blood flow

metabolism

the chemical alteration of drugs to prepare them to elimination

primary site of metabolism

liver

• other sites include kidney, brain, lungs, and intestines

Primary routes of elimination

kidneys: urine major site of drug excretion

gi tract feces, lungs, sweat glands

lipid soluble

have longer half-lives and may accumulate in fat

Arachidonic acid is converted by

COX-1

COX-2

COX-1

enzyme that produces prostaglandins that protect the stomach lining

COX-2

enzyme that produces prostaglandins that cause pain, swelling, and fever during inflammation

COX-2 selective inhibitors

mainly block block inflammatory COX-2 sparing COX-1

COX-1 inhibitors

ibuprofen, naproxen

why naproxen and not ibuprofen?

naproxen has a longer half life

requires less frequent dosing

Why choose COX-2 selective inhibitor?

reduced risk of stomach ulcers and bleeding

NSAIDS produce result in how many minutes

15-30 minutes

Acetaminophen does not cause risk of

gastrointestinal irritation or Reye syndrome

Acetaminophen dose

325-1000 mg every 4-6 hours

Acetaminophen half life

2 hours

common side effect of opioids/narcotics

constipation

pharmacokinetics

study of how the body interacts with administered substances for the entire duration of exposure

Pharmadynamics

study of the biochemical, physiologic, and molecular effects of drugs on the body and involves receptor binding

route of administration: intrathecal

injected into the FLUID around spinal cord

route of administration: epidural

injected into the SPACE around the spinal cord

route of administration: Opthalmic

drops or ointment in the eyes

route of administration: otic

drops in ear

Parenteral

bypassing the digestive system usually by injection

Parenteral routes

intravenous

intramuscular

subcutaneous

intradermal

intrathecal

epidural

site of action

specific molecular location where the drug binds and causes a biological effect

• receptor/protein

main plasma protein

albumin

Only ___________ drugs can leave blood vessels, reach tissues, and cause effects

unbound

agonist

producing a similar effect to the bodys own chemicals

indication

specific reasons or medical conditions that justify use of drug

contraindication

factors or conditions that make using a drug unsafe or inapropriate

grapefruit juice

contains compounds that inhibit liver enzymes responsible for metabolizing many drugs

• can increase the risk of toxicity

side effects

known therapeutic effects that occur when a drugs action extends beyond intended target

adverse reaction

unexpected harmfule or unwanted response to drug

dose response

relationship between the amount of drug administered and magnitude of the bodys response

ceiling effect

drug reaches maximum possible effect

• increasing dose does not help

first pass

orally administered drugs go the liver first and most of it gets absorbed before it reaches systemic circulation