QUIZ 1 Flashcards
Why should OT students study pharmacology – 4 main reasons
- Understand patient’s responses to different drugs
- Determine ideal therapy schedule
- Learn to recognize drug therapy interactions
- Recognize adverse drug reactions and report them
What is Pharmacology?
-Study of how chemical substances affect living tissues
-How chemical agents bind to receptors to enhance or inhibit normal function
What is Pharmacotherapeutics
use of agents to prevent, dx, and cure disease
2 areas of Pharmacotherapeutics:
- Pharmacodynamics: What the DRUG does to the BODY (mechanism of action)
- Pharmacokinetics: What the BODY does to the DRUG (ADME) (how fast)
What is Toxicology?
study of neg. effects of chemicals on living things
What does ADME stand for?
A: Absorption (phase 1)
D: Distribution (phase 2)
M: Metabolism (phase 3)
E: Excretion (phase 4)
List the Enteral routes of administration
- Oral
- Rectal
- Sublingual (under tongue, ie nitroglycerin)
- Buccal (in cheek)
List the 2 primary routes of administration
- Enteric
- Parenteral (injection)
List the parenteral routes of administration
- IV
directly into vein - Subcutaneous
under skin to fat
faster than oral but slower then IM
rate is variable depending on the site
ex: insulin
heat, exercise, massage of the area will facilitate absorption
limb mobility or vasoconstriction from cooling will slow absorption. - Intramuscular
into skeletal muscle ie. flu shot - Epidural
into spinal column outside of dura - Intrathecal
delivered to cerebrospinal fluid (CSF) to get to CNS
Potential Problems with IV
- IV has most potential for harm
- Clot or infection of IV site
- Goes directly into the blood
- Potential for most harm if incorrect drug or dose administered
- Must be performed slowly as IV push
Most convenient administration route
ORAL
- Tablet, capsule, or liquid
- Absorbed across cell membranes or carrier mediated transporters
- Tablets or capsules must disintegrate to release the drug before absorption can take place
o Immediate release
o Extended release
o Enteric–coated ( prevents drug from being absorbed in the stomach until it reaches the intestines)
Breakdown of drugs in GI tract may occur due to:
- Enzymes
- Bacteria present in GI tract
- Acidic environment
- Efflux pumps – pump medication back out into GI tract for elimination
Examples of Inhalation
- Inhaled anesthetics – induce sleep quickly
- Bronchodilators
Examples of Topical
- Cream, lotion, ointment, eye and ear drops
- Not as much systemic absorption unless skin is broken
- Bypasses first pass metabolism by the liver
What is Bioavailability?
- The fraction of a given drug that is actually absorbed into the body’s blood stream from the site of administration
- Example: Fosamax (1-10% oral bioavailability) used for osteoporosis: given on empty stomach 30 min before meal
What is Absorption?
How the drug gets absorbed into the body.
What is Distribution?
- VD = volume of distribution
- Once a drug enters circulation it is then distributed throughout the body
- Total of drug concentration in body / plasma concentration
- If volume of drug is bound to plasma the VD will be small
- If the volume of drug is bound to tissue VD is large
- If a drug is highly bound to plasma proteins, not a lot of drug is available for response
- Only free drug is able to produce an effect
Potential problems of Distribution:
- Blood brain barrier
- Fat loving drugs
- Hard for water soluble drugs to cross blood brain barrier
What is Metabolism?
- How a drug is inactivated and prepared for elimination
- Primarily a function of the liver to decrease drugs lipid solubility and inactivate drug
- 2 phases:
- Phase 1 = metabolism
Inhibitor = grapefruit juice
Inducer = cig smoke - Phase 2 = inactivation of the compound to make it less lipid soluble
What is Excretion?
- Through urine, saliva, breast milk, tears, sweat, lungs, GI, urine and feces are most common
- Renal excretion- glomerular filtration in kidneys through which drugs can be excreted
- Fecal – uptake of drug into liver