Unit 1 Pharmacology final Flashcards
A drug that is a strong inducer of CYP450 enzymes can have what impact on other medications concentrations?
decrease the serum levels of other CYP450 substrates.
— If CYP450 is induced, it will metabolize faster thus clearing the drug quicker from the blood.
What features are taken into account when drugs are classified into groups? (3)
- therapeutic use
- MOA
- Chemical properties
A patient arrives at the ER and is unresponsive. The family found the patient unconscious with an empty bottle of oxycodone 5mg tablets lying beside them. You decide to administer Naloxone to reverse the effects of oxycodone. The EMS started an IV line. What would be the best route of administration to provide the quickest onset of action for Naloxone?
IV
What route of administration that does NOT bypass first pass effect?
- oral
Movement of drug from the site of administration into the bloodstream is the definition of what?
Absorption
What is the most common process of drug absorption and is when the rate of absorption is proportional to the difference in concentration on 2 sides of a barrier?
Passive diffusion
How does lipid solubility affect drug absorption from the GI tract?
Increases absorption
Choose the pH that a weak acid (pKa of 3) would be best absorbed into the blood from the GI tract?
1. 2
2. 3
3. 4
4. 6
2 - the lowest pH would be the best answer
Weak bases would be best absorbed in higher pH levels.
What factors affect distribution of drugs in the body? (5)
- blood flow
- protein binding
- lipid solubility
- drug molecule size
special barriers
A drug that is administered in an inactive form and then metabolized to an active form is known as a ______?
Pro-drug
Which CYP450 isoform is responsible for the metabolism of approximately 50% prescription drugs that undergo oxidation?
CYP3A4
The percentage of a dose of a drug that reaches systemic circulation is defined as:
Bioavailability
Choose the likely volume of distribution for a drug that is 99% bound to plasma proteins:
1. 7L
2. 15L
3. 36L
4. 48L
- 7L
— a drug that is 99% bound only has 1% that can be distributed. Therefore it will be present in the lowest volume option.
Which of the following factors would lead to a high volume of distribution for a drug?
1. protein binding
2. larger drug molecules
3. ion trapping
- Ion trapping
—- 1-2 would lead to low volume of distribution. However, ion trapping keeps more of the drug in the tissues instead of letting it diffuse out of the cells thus causing a higher volume of distribution.
What organ is the driving force behind the elimination of a drug from the body?
Liver and Kidney
You administer an IV antibiotic to a patient every 12 hours and you need to monitor serum concentrations to make sure you reach a therapeutic level without causing toxicity. The drug’s half-life is 12 hours. How many hours will it take for this drug to reach a steady state concentration?
5x the half-life of a drug = steady state
so –> 12x5 = 60 hours.
Doubling the dose of a drug will have what effect on the steady state?
It will double steady state concentration
What is the fastest receptor signaling mechanism?
Ligand-gated ion channels
Patients that have been receiving opiods for long periods of time often require higher doses of these medications to achieve acute and chronic pain control. This higher dose requirement is a result of what mechanism?
Tolerance
A drug that has affinity for a receptor, binds to the agonist binding site on the receptor but does not elicit a response through the receptor is defined as?
Competitive antagonist
This paracrine hormone is released from gastric D cells and inhibits the release of gastric acid when it binds to receptors of gastric parietal cells
Somatostatin
Which neurotransmitter is released after vagal nerve stimulation and interacts with parietal cells and ECL cells to increase gastric acid secretion?
Acetylcholine
This protective factor of gastric mucosa does so via direct stimulation of mucus secretion, decreasing acid secretion and stimulating bicarbonate secretion
Prostaglandins
What damaging factor of gastric mucosa is secreted by gastric chief cells to break down ingested proteins?
pepsinogen (pepsin)
How does the presence of H. pylori in the gut lead to the formation of peptic ulcers? (2)
- tissue damage via cytokine mediated immune response
- decreased somatostatin release via inflammatory mediators
this class of medications used to treat PUD requires active acid proton pumps to exert their action
Proton pump inhibitors (PPIs)
A patient is taking clopidogrel for secondary prophylaxis after suffering from an MI. What medication below would be the LEAST appropriate choice for the treatment of PUD in this patient?
Omeprazole as it prevents the conversion of clopidogrel to its active form.
The chemical property of PPIs allows them to achieve high intracellular concentrations via ion trappi9ng
Weak bases
A patient with a history of seizures has been taking phenytoin for several years. The patient presents today with complaints that are consistent with phenytoin toxicity. Upon questioning you find that the patient has been experiencing heartburn and started taking an OTC medication for relief. What is the most likely culprit of toxicity?
Cimetidine
— cimetidine (H2RA) inhibits CYP3A4 and others that break down phenytoin. So my taking the H2RA, phenytoin has been building up in the patient’s system
A patient (81 y/o male) was admitted for an acute GI bleed (peptic ulcer) and is now experiencing hallucinations and confusion. Patient has a history of chronic kidney disease secondary to DM2. What is the most probable cause of the mental changes?
An H2RA (end in tidine) like famotidine
antiacids allow stomach ulcers to heal by: (2)
- increasing pH (making it more basic)
- by reducing pepsin
This medication forms a protective layer in the stomach by adhering to ulcer craters and gastric epithelial cells
Sucralfate
What are true statements regarding misoprostol? (2)
- it is a prostaglandin analogue
- it has a black box warning use for during pregnancy