Pharmacodynamics Flashcards
Where do drugs come from?
Plants, animals, minerals and they can be made synthetically
Is a synthetic drug worse than a naturally derived drug?
No, a naturally derived drug may not be safer than synthetic drugs.
What can happen if you drink too much Vitamin Water?
High concentrations of Vitamin A can cause liver damage and cause birth defects in pregnant women.
What is the chemical name for a drug?
Identifies the chemical elements and compounds.
What is the generic name for a drug?
Most important name and is usually generally universally accepted. Usually generic names follow a similar pattern based on the class of drugs.
What is the trade name of a drug?
Brand name (Advil)
What is the street name of a drug?
Slang names
Why are brand name drugs more expensive?
They require clinical studies and development to take place. They also have to market and advertise which is costly. When the drug is approved, it is provided a patent for 20 years. This means that no one else can sell or re-create that specific drug during this time frame.
Even after the patent has ended, why are companies able to sell their products at a higher price, than a generic alternative?
They have brand loyalty, and previously had no competition.
Why are generic drugs cheaper?
They do not have to do the clinical research, and there is more competition.
What are the similarities between generic and brand name drugs?
- Must be approved by Health Canada
- Same active ingredient, at the same amount
- Safety
- Efficacy is the same and the time of onset is also the same
How do generic and brand names differ?
- Shape/ Size and Colour (non - medicinal)
- cost
Why do people chose brand name over generic?
People falsely interpret that brand name drugs work better. The increased cost is due to advertising.
What are receptors?
Most drug receptors are proteins that have a primary amino acid sequence that allows it to fold in a specific shape that allows the drug to bind.
The location of the receptor ______________.
The location of the receptor determines where the response will take place.
Do drugs and receptors bind covalently?
No because the binding is not permanent.
What are the four types of receptors?
- Ligand Gated Ion Channels
- G-coupled protein receptors
- Enzyme linked receptors
- Intracellular receptors
What are Ligand Gated Ion Channels? (nicotinic)
Transmembrane receptors. Drugs bind to the outside of the cell. This causes a conformational change that allows ions to pass the gradient, hence triggering the effect.
What are G-coupled proteins? (alpha and beta)
Transmembrane receptors. These cause the release and signal the biological response aka the “2nd Messenger Cascade.”
What are enzyme linked receptors? (insulin receptor)
(outside the cell) Drugs bind to the enzyme and intracellularly actives the enzymatic function
What are intracellular receptors? (steroid)
Receptors inside the cell. These receptors need some sort of fat solubility and have the ability to diffuse and pass the bilayer. The altered transcription causes the effect.
What is an example of an intracellular receptor?
Steroid Receptor
What are the drugs that do not need receptors?
Tums, Osmotic Diuretics, and antibiotics/anticancer.
Why don’t tums need a receptor?
It is purely a chemical process, where acids are neutralized.
Why don’t Osmotic Diuretics need receptors?
Helps to increase urine flow by altering water flow from the kidney.
Why don’t antibiotics/anti-cancers not need receptors?
They directly disrupt the cell membrane.
How does fentanyl and naloxone work in an agonist/antagonistic relationship?
In the body, fentanyl binds to opioid receptors and causes euphoria, pain relief, and at high doses respiratory depression. If an over dose occurs, Naloxone is administered. Naloxone binds to the same receptors as fentanyl but it has a higher affinity for the receptor. It blocks the opioid from binding and sometimes even kicks it off.
Benadryl and Nytol
Benadryl is an allergy medication (therapeutic effect) that has the side effect of drowsiness. Nytol uses the same active ingredient as Benadryl but is reformulated as a sleep aid.
Proscar and Finesterade
Proscar is a drug formulated to help treat enlarged prostates. When prostrates enlarge too much it constricts outflow of urine. When individuals took this medication, it was discovered that it helped to treat male pattern baldness. In certain tissues including the prostrate and hair follicles, an enzyme converts testosterone to dihydrotestosterone. This enzymes causes proliferation in the prostate. In the hair, pushes the follicle outwards and causes hair loss. Proscar, when taken for enlarged prostate inhibits (antagonist) the enzyme from forming DHT, hence reducing enlargement of prostate and preserving hair.
What is the quantal-dose curve?
it used to plot statistics to find the median effective that 50% have met the therapeutic objective.
What is TD 50?
When you increase the dose until it becomes toxic for 50% of the population.
The therapeutic index is calculated by…?
Toxic Effect/Therapeutic Effect
The higher the therapeutic index…..
The higher the therapeutic effect, the safer the drug. This is because there is more wiggle room to increase the dosage.
When deciding the route of administration for patients what should be considered?
Drug characteristics, status of patient and therapeutic objectives.
What are the drug characteristics?
charge, size, pH stability and lipid/water solubility
Status of patient?
age, other drug interactions, ability to flow instructions, and consciousness
What are therapeutic objectives?
- urgency of situation
- long term vs acute treatment
- local vs systemic effects
What are the types of administration?
- Enteral
- Inhalation
- Parenteral
- Topical
What are examples of enteral administration?
oral, sublingual, rectal, and through the GI tract
What are examples of parenteral administration?
subcutaneous, intravenous, and intramuscular
What are the examples of inhalation administration?
Inhalators and nasal decongestant
What are the examples of topical administration?
Systemic transdermal patch, drops, ointments and creams.
