Final review from discussion questions Flashcards
How does alcohol affect the CYP450 system?
alcohol is an inducer, meaning it increases the speed of metabolism
How does grapefruit juice affect the CYP450 system?
Grapefruit juice acts as an inhibitor, slowing metabolism, leading to drug accumulation.
How are drugs excreted from the kidney
-glomerular filtration (for unbound drugs), tubular reabsorption (lipid soluble drugs reenter the blood),
active tubular secretion into the urine).
List all the ways you can think of that one drug might interact with another (hint: pharmacokinetically and pharmacodynamically).
Y-port (both added into the same IV could cause precipitate).
Altered metabolism: induction/inhibition of CYP450
agonist/antagonist
Prior use causing downregulation or upregulation
Altered absorption: antacids, laxatives,
Combined toxicity (both bad for liver, now v bad)
Altered distribution (protein binding inhibitors, pH alterers)
Altered excretion
List some comorbidities of a patient that may result in varied drug responses
Kidney disease, liver disease, intellectual disabilities (ability to remember to take drug), variations in absorption with diarrhea/constipation, nutritional abnormalities leading to lower albumin (higher free drug for protein-bound drugs)
How are drug responses different in neonates?
- Absorption: slower and irregular gastric emptying, lower gastric pH (increased absorption esp of low pK drugs)
- Lower protein binding – higher concentration of free drugs
- immature cyp450, increased drug accumulation (until age 1)
- Lower renal blood flow, GFR and active tubular secretion, accumulation due to less excretion
- More body water, increased Vd
- Less developed BBB, more can reach the brain.
- Cant report early signs of toxicity
How are drug responses different in older adults? (physiologic)
*decreased renal function can lead to accumulation
- Rate of absorption slowed bc of decreased splanchnic circulation (so even though motility is slowed, there isn’t more blood flow to absorb the med so only the rate of absorption is slowed)
- Increased body fat, larger Vd, greater variance in the amount of drug that reaches the site of action
- Decreased albumin, more free drug (@ site of action)
- Prolonged drug effect: Decreased hepatic blood flow (slowed metabolism) and CYP450 activity, decreased 1st pass metabolism (increased effect of PO drugs)
- Changes to receptor # and affinity for receptors
What are two body compartments where ion trapping can be significant (one we can use to our advantage and another can be dangerous).
One place where this is significant is in the fetus, since it has a slightly lower pH (7.3), meaning that substances (basic) which would normally not ionize in the plasma (pH of 7.4) become ionized in the fetus and can lead to a fetal overdose/drug accumulation.
This could be advantageous in the urine where basic drugs (because the urine is acidic) are excreted more easily since they cannot be reabsorbed. Additionally, we could give a drug to make the urine more basic, so more drug would get excreted.
How do we overcome the BBB when giving drugs that we need to reach the CNS?
Inorder to reach the CNS a drug must be able to go thru the cells of the capillary walls, by being lipid soluble or having a transport system
What is the difference between a toxic effect and a side effect?
Toxic effects: negative effects due to excessive drug dose. Side effect: nearly unavoidable effect at therapeutic dosage
Which populations are particularly sensitive to drugs? (select all that apply)
- older adults
- neonates
-teens
- pregnant women
older adults and neonates
While pregnancy does have many considerations for drugs (like increased GFR, increased hepatic metabolism (more drug clearance, may need lower doses), increased GI transit time (increased absorption, may need lower doses), they are not considered sensitive because normal drug doses don’t necessarily (although they can) have an increased effect (or adverse effects)
Can we give epinephrine PO? Why or why not?
No, since it has a short half life, and since it is a catecholamine, it is degraded in the liver, meaning most of it would never enter the bloodstream if given PO
Where are MAO and COMT located?
MAO: Mostly presynaptic terminal
COMT: Mostly liver, some free
What is the difference between Catecholamines and noncatecholamines?
The half life of catecholamines is much shorter due to COMT and MAOs, so they cannot be given PO. Non-catecholamines can be given PO and can cross the BBB while catecholamines cannot. Catecholamines are reuptaken into the presynaptic cleft (MAO here, some COMT), while non-catecholamines are broken down in the liver
Which receptors does Dobutamine interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects?
B1, A1 at high doses
Inotrope - increases cardiac contractility w/o increasing HR or BP much- used in CHF
dilates coronary arteries
Synthetic catecholamine
Agonist
Which receptors does Isoproterenol interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects? What are cautions for this medication?
“Chemical pacemaker”
Synthetic catecholamine
Agonist of beta 1 and 2 equally
effects of increased HR and contractility, when combined with CAD can lead to an MI
Which receptors does Dopamine interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects? Main indication
dopaminergic, also B1 in high concentrations and B2 in even higher concentrations, in highest concentrations a1 agonist
Dose dependent actions:
low renal dose: dilation of renal, splanchnic and cerebral arteries
slightly higher dose: increased contractility without increased HR, vasodilation (and renal dose effects)
high dose: vasoconstriction (main indication is hypotension)
Which receptors does Ephedrine interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects? How is this one different?
blocks NE reuptake, A1, A2, B1,
indirect acting agonist, can cross the BBB
Which receptors do Labetalol and Carvedilol interact with? Do they agonize or antagonize these receptors? What are the major pharmacologic effects?
“Adrenergic antagonist”
B1=B2, also hits alpha receptors in large doses
Antagonist
Vasodilation, decreased HR, decreased BP, CO uneffected
Which receptors does Phentolamine interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects?
A1=A2
Antagonist
HTN emergencies – causes vasodilation, decrease BP and increased HR
Extravasation – help reverse extreme constriction if norepinephrine extravates
Which receptors does Prazosin interact with? Does it agonize or antagonize these receptors? What are the major pharmacologic effects/side effects?
A1 antagonist selective
Effects: vasodilation, prostate relaxation
Orthostatic hypotension, reflex tachycardia d/t lower BP
Also treats BPH!
What are the pharmacologic effects of drugs that:
antagonize M
ACh inhibitors
antagonize and agonize Nm
M antagonists and Ach inhibitors block PSNS activity
Muscarinic antagonists to control overactive bladder
Drugs that both antagonize and agonize Nm don’t have a lot of clinical application
Drugs that antagonize Nm and their effects
rocuronium, vecuronium; prevent muscle contraction, flaccid paralysis
What receptors does Scopolamine act on? Agonize or antagonize?
Major pharmacologic effects
difference from other drugs in class
muscarinic antagonist
sedation???, mydriasis, sea sickness prevention
What receptors does Glycopyrrolate act on? Agonize or antagonize?
Major pharmacologic effects
difference from other drugs in class
muscarinic antagonist, does not cross BBB, so only peripheral effects (quaternary ammonium)
What receptors does Ipratropium act on? Agonize or antagonize?
difference from other drugs in class/indications
muscarinic antagonist,
used in the treatment of asthma/COPD
What is the difference between Neostigmine and Pyridostigmine?
While both are Ach inhibitors, used for myasthenia gravis, and NMB reversal, Neostigmine can also be used to increase gut motility and Pyridostigmine can be used for glaucoma.
How do a transdermal birth control patch and the vaginal contraceptive ring work?
It works the same as oral birth control by inhibiting ovulation and thickening cervical mucus. Vaginal contraceptive ring can also cause some local irritation
How does the subdermal etonogestrel implant work?
It lasts for 3-5 years and has only progesterone, can cause some irregular vaginal bleeding
What is Depot medroxyprogesterone acetate? How does it work? Warnings?
Birth control given by IM or sub q injection, works by inhibiting FSH/LH secretion. It can cause bone loss, so it is not recommended for more than 2 yrs
Copper IUD vs levonorgestrel IUD
Both IUDs work by creating local inflammation. The copper IUD can be used as emergency contraception up to 5 days after fertilization), and can last for up to 10 yrs. levonorgestrel is a hormonal IUD that thickens cervical mucus, inhibits ovulation and alters the endometrium
emergency contraceptives
progestin only: decreases pregnancy btwn 84-89%, will not terminate existing pregnancies or harm fetus, adverse effects of heavy bleeding, or GI upset
Progestin agonist/antagonist or copper IUD can be used up to 5 days after fertilization
Blood is hypotonic: meaning, what is given
meaning: low solutes in blood, fluid going into cells,
give: hypertonic fluids (3% or 5% NaCl, 10% dextrose water (D10W)
Blood is isotonic: meaning, what is given
meaning: blood = same as cells about 280-300
give: isotonic (NS (0.9%), D5W)
Blood is hypertonic: meaning, what is given
Meaning: blood has high solutes (>300), risk for cellular dehydration
give: hypotonic (1/2 NS 0.45% NaCl)
Can we give desmopressin (DDAVP) for hemophilia A? Why or why not? Describe the mechanism of action of the drug.
This drug releases factor 8 clotting factors from the vasculature into the blood, it can be given for hemophilia A because the issue is producing/releasing these factors, so it increases the amount of factor 8 in the blood. It is preferred for mild forms
Understand the general ACC/AHA guidelines for the management of blood cholesterol. (In general, I don’t need you to memorize little details).What is the purpose of these guidelines?
The purpose of the guidelines is how to decide who to treat and to what intensity they need to be treated. It separates patients into two categories (high and very high risk), and subdivides high risk by age to determine who should receive the most aggressive statins
Who should be screened
Who is at risk (ASCVD 10 yr risk assessment)
Treatment: lifestyle modifications + low/med/high drug therapy
How should your patient’s HMG-CoA reductase inhibitor dosing be adjusted with acute renal failure?
Their CK should be checked, if it is elevated (which it will be) the drug should be discontinued
Discuss HMG-CoA reductase inhibitors and myopathy. What are the s/s? What are the risks? What can happen in severe cases? How do you educate your patients to monitor for this?
s/s: aches, tenderness, weakness, can progress to myositis, with increased CK and K+
Risks: female, old age, low BMI, chronic liver or kidney disease, higher statin dose, CYP34A inhibitors, OATP1B1 inhibitors, specific genetics
Watch for s/s: measure CK upon start of therapy and again if symptomatic
What is the difference in mechanism of action between warfarin & heparin? Why do you think a patient would be prescribed one over the other?
Heparin works by binding anti-thrombin → suppresses fibrin mesh formation. Heparin works relatively quickly, and can only be given via IV or sub Q injection, so it is typically only given inpatient.
Warfarin inhibits activation of vitamin K so clotting factors 2, 7, 9, and 10 are decreased, leading to lessened clots (decreased fibrin formation). Warfarin can take a while to work, and is oral so it is a medication patients are sent home on to prevent future clots.
Name the 4 classes of antidysrhytmics and describe how they work
1 - na+ blockers
A = increase AP, ERF, QT interval
B = decrease AP, ERF
C= increase ERF only in AV node
2 - beta blockers
3 - k+ blockers, delayed repolarization, increased AP duration, increased ERP, prolongs QT,
4 - decrease HR, contractility, conduction thru AV node
Other
Adenosine - hyperpolarizes by opening K+ channel,
Digoxin - na+/k+ inhibitors, increasing ca2+, thus increased contractility,
Name the 4 classes of antidysrhythmics and what they are used for
1 - na+ blockers
A = Atrial and ventricular arrhythmias,
B = Post MI and other ventricular arrhythmias
C= SVT and afib
2 - beta blockers - SVT, VT, post MI
3 - Ventricular tachy
4 - SVT
Other
Adenosine - tachycardias where pt is unstable
Digoxin - heart failure and supraventricular dysrhythmias
What is the difference in mechanism of action between the nondihydropyridines and dihydropyridines? How does this difference alter their clinical effects?
dihydropyridines only affect the vasculature, can cause reflex tachycardia, contractility increase, while nondihydropyridines affect both the vasculature and the heart rate, decreased contractility and AV node conductivity
-grel
P2Y12 ADP agonists
-teplase
thrombolytics
-stim
leukopoetic growth factors
-dipine
dihydropyridines
-xaban
factor 10 inhibitors
-parin
anticoagulants that activate antithrombin (like heparin)
-sartan
ARB
-pril
ACE inhibitor
-fibr-
fibric acid derivatives
What is the half life of thrombolytics
5 mins
-gline
MAO-B inhibitors
-Phylline
methylxanthines
-dronanate
bisphosphonates
does sodium nitroprusside cause reflex tachycardia
no
Hypo/hyper kalemia with digoxin
hypo: toxic
hyper: subtheraputic
Q
nursing considerations for Calcitonin gene related peptide receptor antagonist
high fat meal can delay aborption by as much as 2 hours
How do inhalation anesthetics reach their site of action? Where is their therapeutic site of action
They reach their site of action through the lungs (concentration, solubility, blood flow and ventilation all play a role in their absorption)
Their therapeutic site of action is the CNS
Go through each body system and describe the effects that opioid agonists have. How are these adverse effects managed? (i.e. cough suppression can be managed by teaching your patient to deep breath & cough at intermittent intervals to clear secretions & prevent PNA)
Constipation - fiber, fluid, activity, stool softener, laxative
Miosis – usually not a problem
Respiratory depression – monitor, if needed stop opiods and give narcan. Elderly, young and those with respiratory disease are especially at risk
Decreased heart rate – stand up slowly to help avoid and limit orthostatic hypotension
Urinary retention – monitor I/Os
Orthostatic hypotension – educate pts
Cough suppression – educate pts to breath deep and cough, auscultate for crackles
Euphoria, emesis, birth defects, tolerance, neurotoxicity
Why do we avoid ergot alkaloids & triptans together?
We avoid ergot alkaloids and triptans together because they can cause excessive vasospasm
What phramacologic measures can be used to treat heart failure
REDUCE PRELOAD (Diuretics ACEi, ARBs, aldosterone antagonists, Venodilation)
REDUCE AFTERLOAD (ACEi, ARBs, BB (controversial, use w/ caution), Arteriole vasodilators)
INCREASE INOTROPY (CONTRACTILITY) (Cardiac glycosides (digoxin), Dopamine/dobutamine (sympathomimetics)
What are the differences between cardiac beta1 blocker action and cardiac calcium channel blocker action?
Calcium channel blockers cause arteriole vasodilation, while beta blockers cause decreased renin release. Both BB and nondihydropyridines decrease HR, AV node conductivity and decreased contractility
List absolute contraindications for nondihydropyridines
Drug interactions: beta blockers, digoxin
Don’t want to use with anything that would cause low contractility
Why does digoxin cause increased urine output?
Increased cardiac output = improved tissue perfusion = improved renal blood flow = more glomerular filtration = increased UOP!
When giving any medications that suppress immune responses, what are points of patient education? (hint: re: illness, infection, vaccines)
Before starting treatment, patients should become up to date on vaccines, since once the immune system is suppressed, it will be hard for the immune system to create new antibodies, and person will need increased immunity because they have less of an ability to fight infections
Once treatments are started the person is considered immunocompromised, so they should avoid sick people and encourage loved ones to get vaccinated to prevent giving them illnesses
Avoid concurrent administration of multiple immunosuppressants
These meds can also be very expensive, and are sometimes not covered by insurance