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
What OTC medication used for stomach problems causes black stools?
Bismuth subsalicylate
Triple therapy for H. pylori PUD is no longer first line because of diminished efficacy due to bacterial resistance to what medication?
Clarithromycin
Triple therapy included:
– clarithromycin
– amoxicillin or metronidazole if allergic
– PPI
What drugs are used in Quadruple Therapy for H. pylori?
- PPI (usually omeprazole)
- Tetracycline
- metronidazole
- bismuth subsalicylate
What medication increases lower esophageal sphincter tone by antagonizing D2 dopamine receptors?
Metoclopramide
Metoclopramide has an FDA black box warning for what?
Tardive dyskinesia
What is first line choice for the treatment of chronic constipation includes agents of what drug class?
Bult forming laxatives
Loperamide (Imodium) targets what receptors to produce anti-diarrheal outcomes?
opioid
Ondansetron targets receptors in which part of the emesis pathway to treat nausea and vomiting?
- Stomach
- solitary tract
- Chemoreceptor trigger zone
What neurotransmitter would be found in a synapse of a post-ganglionic parasympathetic neuron?
Acetylcholine
– parasympathetic neurons use acetylcholine at pre and post ganglionic synapses
What neurotransmitter does Alpha1 use and what function does it produce?
norepinephrine and epinephrine
vasoconstriction
What neurotransmitter does Beta1 use and what function does it produce?
norepinephrine and epinephrine
increases heart rate
What neurotransmitter does Beta2 use and what function does it produce?
epinephrine only
bronchodilation
What is the main function of Alpha2 receptors?
Feedback inhibition
Which process would result in lowering heart rate or bradycardia?
Ach release and activation of muscarinic (M2) cholinoceptors
–Ach is released by the parasympathetic pathway (rest and digest) slowing heart rate.
–NE & Epi are released by the sympathetic (fight/flight)
– Parasympathetic act on muscarinic receptors
– Sympathetic act on alpha and beta (nicotinic) receptors
The receptor on which post-ganglionic parasympathetic neurotransmitter acts in the heart is what?
Muscarinic (M2) cholinoceptor
what mechanism is most responsible for the termination of action of norepinephrine at the post-ganglionic neuronal synapse?
reuptake into the synaptic nerve terminal
other mech: diffusion out of the cleft
Compared to ACE-I, ARBs do what? (4)
- cause less cough
- are equally cardioprotective
- are equally renalprotective
- are better tolerated
What patients can safely receive a beta-blocker?
heart failure patients and ischemic heart disease patients.
–avoid in patients with severe asthma or COPD as they would prevent Beta2 from causing bronchodilation. Giving a beta-blocker to a patient who already has trouble breathing would be problematic.
What antihypertensive medications are less effective in treating the black patient population?
ACEs (pril) and ARBs (sartan) and beta-blockers
but mainly the first 2
A 3 month pregnant patient has been diagnosed with hypertension. What medication class is absolutely contraindicated for use?
ACE(pril)/ARBs(sartan)
What hypertension medication would be most likely to cause orthostatic HYPOtension?
Alpha-1 blockers would be the most likely like prazosin
others that could cause orthostatic hypotension –Dihydropyridines - CCBs
– ex amlodipine
Which beta blockers also have vasodilating effects? (3)
Carvedilol
labetalol
nebivolol
When reviewing routine labs for a patient with newly diagnosed HTN, you discover the patient has abnormally high serum calcium. What medication is most likely responsible?
Thiazide diuretics
– they also cause
—–hypokalemia
hypomagnesemia
hyperuricemia
hyperglycemia
dyslipidemia
This medication decreases blood pressure by reducing cardiac output, inhibiting the release of renin from the juxtaglomerular complex in the kidneys
Beta-blockers
- propranolol for example
A male patient with HTN and heart failure started a new drug that will help with both disease states. The patient returns 3 months later complaining of breast enlargement. What medication may be the cause?
Spironolactone
–H2RAs can also cause gynecomastia
A 57 y/o Caucasian male with a history of gout has just been diagnosed with hypertension. The patient has no other health issues. What is the most appropriate first line treatment for this patient’s HTN?
ACE/ARB
– thalazides, loop diuretics can cause hyperuricemia (gout)
What drug targets Alpha2 receptors for treatment of hypertension?
sympatholytics
–Clonidine has biggest effect out of the class
others–Methylodopa, Guanfacine, Guanabenz
What medication can result in renal failure in a patient with renal artery stenosis?
ACEs/ARBs
How do ACEI cause hyperkalemia (increased potassium)?
They decrease the aldosterone driven secretion of potassium in the collecting tubules
What medications are NOT associated with hyperkalemia?
CCBs (pine)
Thalazides - they can cause hypokalemia
loop diuretics - can cause hypokalemia
ACE (pril)/ARB (sartan), potassium sparing diuretics,
Hypokalemia can result from treating hypertension with what meds?
Thalazides - hydrochlorothalazide
Loop diuretics
LDL stays in the plasma for a long time because?
It does not have high affinity for the LDL receptor which slows its uptake.
–It also has apoB100 as its only transporter
HMG-CoA reductase is an enzyme involved in the process of what?
Synthesizing cholesterol from acetyl-CoA
The exogenous and endogenous lipoprotein metabolism pathways consists of what organs respectively?
Small intestine and liver
LDL can be differentiated from other lipids because?
Because it only has apoB100 apoprotein attached
Oxidized LDL in the sub-endothelial spaces causes what? (4)
1.Injury to the endothelia cells
2. promotes monocyte chemotaxis
3. foam cell necrosis
4. release of enzymes that damage the intima of the blood vessel
HDL is responsible for the transport of what back to the liver?
cholesterol and lipids
HDL performs what actions to reduce adverse coronary events? (4)
- improves endothelia function
- reduces oxidation of LDL
- reduces damage from oxidized LDL
- Has anti-inflammatory effects
Of the drug classes, which one contains the most effective medications for lowering serum LDL levels?
Statins (HMG-CoA reductase inhibitors)
–fibrates are best for reducing triglycerides. Fish oil may also help reduce triglycerides
What are the pleiotropic effects of statins? (3)
Plaque stabilization
inhibition of LDL oxidation
inhibit platele aggregation
Which statin has a half-life longer than 8 hours?
Atorvastatin, pitavastatin, and rosuvastatin
- the rest have less than 4 hours for a half-life
Pravastatin (and statins in general) can cause what adverse effects? (4)
muscle pain
increased aminotransferase activity
increased creatine kinase
altered lipid metabolism in breast feeding infants
The use of statins in patients with risk factors but no previous coronary heart disease has been shown to do what?
decrease the risk of cardiovascular events
Fibrates are primarily used to treat what?
Hypertriglyceridemia
What are the overall effects of Niacin on the lipid profile?
Decreases LDL
decreases triglycerides
increases HDL
What can be done to reduce the adverse effects of flushing when taking Niacin?
Take aspirin 30 minutes prior to taking niacin
The result of the mechanism of action of cholestyramine is what?
It causes an increase in LDL receptor expression by the liver.
– it prevents bile from being reabsorbed.
What agent lowers blood cholesterol by decreasing intestinal absorption of dietary cholesterol?
Ezetimibe - only drug in the class of cholesterol absorption inhibitors
The use of omega-3 fatty acids in fish oil is expected to do what to plasma lipids?
Decrease triglycerides
A patient has just be discharged from the hospital following an MI. What medication should be started in the absence of contraindications?
Statins
Which statin drugs undergo CYP3A4 metabolism?
All except pravastatin, pitavastatin, and rosuvastatin
