Intro To Pharm Flashcards
What is the responsibility of a PT in regards to patients on medication?
- Be able to recognize adverse effects
- Act accordingly
- Know side effects in order to ensure patient safety.
What is pharmacology?
The study of drugs
What is the definition of a drug?
Any substance that, when taken into a living organism, may modify one or more of its functions.
-They can alter physiology, be harmful or beneficial, and can be synthesized or a naturally occurring compound.
What is pharmacotherapueitcs?
The study of the therapeutic use and effects of drugs in the treatment or prevention of disease.
What does toxicology mean?
Harmful effects of chemicals “side effects” or adverse effects.
Define pharmacokinetics
What the body does to the drug. It is the movement of a drug into, though, and out of the body.
Define pharmacodynamics
How a drug affects the body
What is the Drug Approval process?
- Identify a new drug need.
- develop molecule
- Includes animal studies - FDA IND approval
- Investigational new drug - Clinical Trails
What is the first stage of a clinical trial?
Safety; small numbers; It is mostly done on healthy subjects unless is it toxic.
What is the second stage of a clinical trial?
Efficacy; small number that is in the hundreds; usually trialed on people with the disease; compare to placebo or current drug
What is the third stage of a clinical trial?
Larger and Longer; large group of participants; randomized and double blind
What is the fourth stage of a clinical trial?
After FDA approval, post marketing
What does it mean if a drug is “off patent”?
Last 20 years, and after that other companies can make the drug.
What does off label mean?
Used for an unapproved indication or in an unapproved age group, dosage, or route of administration.
What is the orphan drug act?
Provides grants for drugs less likely to be studied
What is treatment investigational new drugs?
Streamline approval process if drug is for life-threatening condition.
What does ADME stand for? What process is is apart of?
Absorption, distribution, metabolism, and excretion.
It is apart of pharmacokinetics.
What is absoprtion?
The process by which a drug is transferred from site of administration to the systemic circulation.
What are the two types of routes a drug takes for absorption into the body?
- Enteral - via the GI Track
2. Parental - via not the GI track
What are the different enteral routes?
- Oral = tablets, capsule, syrup, solution, gum, sublingual, buccal
- Rectal = suppository, suspension
What are the different parental routes?
- Injection = IV, IM, subcutaneous, intra-arterial, intrathecal, epidural, interosseous, intraperitoneal
- Inhalation
- Topical
- Transdermal = patch, electrical, ultrasound
- Implant
What are the 3 main pathways that a drug takes to get to its target?
- passive diffusion through lipid membrane
- passive diffusion through aqueous channel
- carrier mediation (binds to a protein
What are factors that impact drug movement?
- Lipophilicity
- Size of a drug molecule
- Membrane thickness
- Acidic vs. Basic Molecules
- Concentration gradient
- The blood brain barrier
What is the BBB and how does it effect absoprtion?
It is cells that serve as a boundary between blood and CNS fluid.
- It is semipermeable
- More permeable in some infections or diseases like MS
- Smaller, more lipid soluble meds can more easily cross the BBB.
- When drugs cross the BBB, there might be more CNS related ADRs (dizziness, drowsiness)
What are some barriers to delivery that are associated with absoprtion?
- User Error
- Lipid solubility, degree of ionization
- Fast/slow gastric emptying
- Food or drug interactions
- Bioavailabilty
- First pass metabolism/effect/elimination
What factors that determine the rate of distribution?
- Lipid solubility and degree of drug ionization
- Organ blood flow
- molecular weight
- local metabolism in any tissue other than the target organ
- binding to plasma proteins
How is distribution measured?
Vd = total concentration of drug in the body/ plasma concentration
What determines a higher volume of distribution?
It means there is less drugs binding to a protein so there is more active drug in the tissue.
What determines a lower volume of distribution?
More drug binding to protein means there is less active drug in the tissue.
What 3 factors effect protein binding?
- disease state
- nutrition
- drug interactions
What is metabolism?
How a drug is inactivated and prepared for elimination
What is the 1st phase of metabolism?
It is a catabolic process that it catalyzed by CYP450 enzymes. It takes a drug from a large molecule to a small molecule.
What are the derivatives of the 1st phase of metabolism?
- Usually inactive molecule
2. Sometimes active molecule
What is the 2nd phase of metabolism?
It is a conjunction reaction.
Add hydrophilic group = less lipid soluble = more likely to excrete via the kidneys.
What are CYP enzymes?
Enzymes that catalyze reactions in order to break down drugs into active or inactive products. The mainly occur in the liver.
Why do CYP450 enzymes matter?
They break down drugs into active or inactive products.
Some drugs induce or inhibit CYP - bind to the enzyme to change its activity or change gene expression so that more or less enzyme is produced. It is key in drug-drug interactions.
What is the common routes of elimination?
- Urine via kidneys
- Fecal via liver - bile fluid - intestine
* Can also be excreted by exhalation, tears, breast milk, saliva, sweat
What are the properties of first order elimination?
- It is the most common.
- The elimination (units per hour) is proportional to drug concentration
- Has a constant half-life
What are the properties of the zero order elimination?
- It is less common
- elimination rate is constant and independent of concentration.
- saturate elimination mechanisms
- inconsistant half-life
What is a half-life of a drug?
It is how long it takes to eliminate 50% of a drug.
When is a half life considered cleared? Why is it important?
At 5 half-lives.
Because you can calculate when the drug will be out of a person.
What is the steady state?
When the amount of drug excreted in a specific period is equal to the amount of drug administered; often time to reach therapeutic effect.
How many half lives does it take to reach the steady state?
4-5
