Advanced Pharmacology Exam 1
What is distribution?
How a drug will be transported to the tissues it needs to go to in order for it to exert its effects
Quickest route of absorption? Slowest?
IV = quickest IM = slowest
Where will a drug absorb if it is a weak base that ionizes at a pH of 4 and lower?
In the small intestine (since the stomach has a pH of 2-4, so the drug will become ionized and move to the small intestine where it will be able to absorb into the bloodstream)
Protein bound means:
Inactive form of the drug; does not have any therapeutic effect when bound to a protein
Why do we monitor albumin?
Indicative of nutritional status and how well protein-bound drugs will be transported to their target locations
How do antivirals work?
Interfere with the virus' replication within the host cell
How does Augmentin work?
Irreversibly binds to bacterial beta lactamases which protects the penicillin drugs from destruction. The clavulanic acid protects the penicillin from being broken down by the bacteria (combats bacterial resistance).
Why is it important to monitor vancomycin levels?
It has a narrow TI. Dose has to be adjusted according to amount of vanco in the blood serum (draw a vanco trough 1 hour before the next dose is due)
What is an enzyme inducer?
It increases clearance of the drug (decreased blood levels of drug--may need dose increase)
What does it mean when a drug is ionized?
It means that the drug is stuck in the compartment it was ionized in and has to be moved to the next compartment (cannot be absorbed into the bloodstream)
What does a substrate for an enzyme mean?
It needs it to undergo metabolism
What is an enzyme inhibitor?
It reduces clearance (increased blood levels of drug--may need dose decrease)
Major side effect of Bactrim:
Kidney stones if patients don't hydrate well
How to determine when drug will be cleared from body:
Multiply half-life of drug by 4 Ex: Half-life of drug A = 8 hours 8 x 4 = 32 hours (how long you'd need to wait before starting the contraindicated new drug B)
What is the purpose of a DEA #?
Needed to prescribed scheduled drugs
Major side effect of aminoglycosides (like Gentamicin):
Oto and nephrotoxicity
What is the 1st pass effect?
PO drug goes through GI tract and absorbs in the stomach or intestines into local circulation that reaches the liver. The liver inactivates portions of the drug before it goes into systemic circulation. Some drugs with a very high 1st pass effect may have to be given IV (goes directly into systemic circulation) or in higher PO doses (watch for side effects)
What is the most common way drugs pass through cell membranes?
Passive diffusion
Major side effect of Tetracyclines:
Photosensitivity and teeth stains in kids
What is the PDMP?
Prescription Drug Monitoring Program Used to effectively track patient's controlled substance uses across different health facilities (in the same state)
What are clinical practice guidelines?
Recommendations that are intended to optimize patient care that are informed by a systematic review of the evidence and an assessment of the benefits/harms of alternative care practices Ex: sepsis, CAP
Major side effect of Vancomycin:
Red-man syndrome (if given too quickly)
Where do weak bases absorb?
Small intestine
What characteristics of a drug allow it to pass most quickly through cell membranes (usually through passive diffusion)?
Small, uncharged (unionized), lipid soluble--pass through membrane without any energy
What happens when a patient is on two drugs that are competing for the same protein binding site on the albumin?
Some drug interactions can occur. Drugs fight for binding position, but both drugs do not get enough as the usually would. Leads to higher free drug levels, decreased overall albumin binding, and potential toxicity for both drugs. **Unpredictable**
What is therapeutic index?
Statement of the relative safety of a drug
Where do weak acids absorb?
Stomach
What are the components of bactrim?
Sulfamethoxazole: Disrupts production of dihydrofolic acid Trimethoprim: Disrupts production of tetrahydrafolic acid Together these drugs target different steps in the folic acid pathway that kills susceptible bacteria better than either drug would alone
How does antibiotic resistance occur?
The bacteria find a way to become resistant to the antibiotic. They multiply leading to an ineffective antibiotic
What happens to the therapeutic effect of a drug when the patient is elderly and has very low levels of albumin?
The drug does not bind to the protein (albumin) as much as expected, so there is a lot of free drug floating in the plasma; high risk for drug toxicity
What is the minimum effective concentration?
The minimum amount of drug required to produce a therapeutic effect
What is a drug's half-life?
The time it takes for the concentration of a drug in the body to be reduced by 50%
What is pharmacokinetics? What are its 4 categories?
What the body does to the drug 1. Absorption 2. Metabolism 3. Distribution 4. Excretion
What is pharmacodynamics?
What the drug does to the body
What is antibiotic synergy?
When 2 antibiotics are combined in one combination drug to improve efficacy Ex: Bactrim, Augmentin, Zosyn
Why is knowing half-life important?
When switching to another drug that cannot be given with the previous drug.
What is important to keep in mind when treating URIs in young infants?
Young infants are not fully vaccinated yet, so antibiotic treatment of URIs may be necessary
What is receptor desensitization?
Decreased responsiveness of the receptor to the drug; decreased overall effects
How can we manipulate the urine pH in cases of overdose?
Drugs that are weak acids (aspirin) can be trapped and excreted through the urine. We raise pH of the urine (with sodium bicarb) to force the drug to ionize and allow it to be excreted, not reabsorbed through the bloodstream.
Once you graduate from an NP program, in order to prescribe you'll need:
-Advanced nurse prescriber license -DEA #
How do superinfections develop?
-Broad spectrum antibiotics -Several antibiotics over a short period of time
What are the key pharmacokinetic changes that occur during pregnancy?
-Decreased absorption -Increased hepatic metabolism -Increased renal excretion **Dose adjustments are common during pregnancy
How to prevent antibiotic resistance:
-Don't prescribe for viral infections -Only prescribe when needed -Use the right dose and duration (use guidelines) -Utilize cultures -Reassess treatment regime after cultures come back (don't just use broad spectrum drugs) -Only use prophylactic antibiotics when completely necessary
Common causes of medication errors:
-Illegible writing -Drug names that sound alike -Medications that look alike -Administering a drug with the wrong route
Drug factors related to distribution:
-Lipid solubility -Molecular size -Degree of ionization -Duration of action -Cellular binding -Therapeutic effects -Toxic effects (lipid soluble, small, and non-ionized drugs will distribute more quickly)
Which antibiotics are not safe for children (age less than 12)?
-Tetracycline (bones and teeth) -Fluoroquinolones (tendon rupture)
Body factors related to distribution:
-Vascularity (poor perfusion, disruption of blood flow due to trauma--difficulty distributing) -Blood barriers (blood-brain-barrier can be problematic if we need to get drugs to the brain--will need very high dosing since only a small amount of the drug will get through) -Transport mechanisms -Plasma binding proteins -Disease states -Volume of distribution -Drug interactions
Rules for prescribing Schedule II drugs:
-Written script needed -1 month supply only -No refills
pH of stomach:
2-4
pH of bladder:
5-8
pH of large intestine:
6-7
pH of small intestine:
6-7
pH of breastmilk:
7.1
pH of bloodstream:
7.35-7.45
You have prescribed an IV aminoglycoside for a patient who has a severe infection in her leg. What would be important to monitor this patient for related to this class of antibiotics? A. Renal dysfunction B. Liver dysfunction C. Serum glucose levels D. Visual disturbances
A - When patients are taking aminoglycosides (i.e. gentamicin), they need to be closely monitored for any signs of renal dysfunction - Usually we follow BUN/creatinine labs and urine output as clinical indicators of worsening kidney function
Who is at risk for drug toxicity?
Elderly, those with decreased renal function -Cannot properly excrete the drug
A patient has a SNP that creates greater than normal amounts of very efficient/ active forms of CYP 3A4. This is the enzyme that deactivates drug G. Which of the following is accurate? A. This patient will need higher doses of drug G in order to have the expected reaction. B. Because this patient is an ultra-metabolizer, they need to be monitored for drug toxicity when give standard doses of drug G. C. For safety reasons, this patient should not be give drug G or any other drugs metabolized by CYP3A4. D. This SNP will not affect the serum levels of the drug so no changes are needed.
A Because the drug is inactivate by the enzyme and the patient is making more of the enzyme than expected, the pt would need to take higher doses than usual to get the expected effect.
A patient presents with fever and malaise and a one day history of an itchy erythematous rash unilaterally along dermatome T12 . The APRN strongly suspects that it is herpes zoster though no pathognomonic vesicular lesions are present. Which of the following is the most appropriate approach to this situation? A. Treat immediately with oral valacyclovir TID for 7 days. B. Treat BID with famiciclovir once the vesicles appear to be sure it is herpes zoster. C. apply zovirax ointment to the rash six times a day until the rash is resolved. D. Slowly Infuse IV cyclovir over an hour twice a day for 5 days.
A Tx of zoster should be systematic not topical & needs to begin ASAP but IV tx is not indicated.
Which side effect of clindamycin causes the provider the most concern and may warrant discontinuation of the drug? A. Diarrhea B. Vomiting C. Nausea D. HA
A - C. Difficile-associated diarrhea (CDAD) is a serious and sometimes life-threatening superinfection associated with clindamycin use - Typically the drug is discontinued immediately, cultures are drawn, and the C. Diff is treated if confirmed
You have recently graduated from an NP program and are exploring licensure in a variety of states. Prescribing authority is ... A. determined by state law B. the same for PAs and APRNs C. the same in all states D. regulated by the federal government
A - Individual states determine prescribing authority regulations, so you'll need to check these in the state you want to practice in - The federal government isn't involved in this and there are definitely differences between PA and APRN prescriptive authority laws
You are caring for a patient who is being treated with gentamicin and fluconazole. If these 2 drugs are competing with each other for protein-binding sites, what would be the result? A. Altered efficacy of both drugs B. Counteract any positive benefit the drugs would have C. There will be no problems giving these drugs together D. Puts the patient at risk for an allergic reaction
A When 2 drugs compete with each other for protein-binding sites on albumin, this alters the effectiveness of both drugs (and can also cause toxicity of both drugs) due to inconsistent binding and free drug concentrations in the plasma
Which is safer: a wide TI or a narrow TI?
A wide TI is safer (more dosing options before reaching toxic effects)
You determine that a patient requires a prescription for a narrow-spectrum antibiotic to treat a gram positive cocci-related infection. What treatment options would you consider? (Select all that apply) A. Erythromycin B. Penicillin G C. Tetracycline D. Vancomycin E. Amoxicillin
A, B, D - Erythromycin, penicillin G & vancomycin are all considered narrow-spectrum drugs and are great for treating gram positive cocci infections - Tetracycline & amoxicillin are considered broad-spectrum drugs
While rational drug selection is based on the individual patient the aspect of rational drug selection addressing disease-specific information by a national medical or nursing organization is A. a guideline B. cost C. availability D. patient hepatic and renal function
A. A guideline
Mr. G, PA is recent graduate of a master's degree PA program. His program has prepared him in prescribing using rational drug selection. He feels confident that he can promote positive outcomes when prescribing. He is exploring licensure in a variety of states. (Ch. 1) Several factors influence PA or APRN prescribing authority. Prescribing authority is: A. determined by state law B. the same for PAs and APRNs C. is the same in all states D. regulated by the federal government
A. Determined by state law
Which scheduled drugs can be called into a pharmacy? A. Schedule 5 B. Schedule 1 C. Schedule 3 D. Schedule 2
A. Schedule 5 C. Schedule 3 - schedule I is not prescribed for use in Wisconsin - schedule II needs to be written prescription
Free drug means:
Active form of the drug (available for therapeutic effect)
What is the key plasma protein involved with protein binding for medications?
Albumin
Major side effect of Penicillins/Cephalosporins:
Allergies
How many half-lives does it take to remove most of the drug from the body?
Appx 4
You have ordered intramuscular (IM) injections of morphine, a narcotic, every 4 hours PRN to treat pain in a patient who was in a motor vehicle accident. Under what category would morphine be classified? A. Schedule I B. Schedule II C. Schedule III D. Schedule IV
B Narcotics have a high potential for abuse and are classified as Schedule 2 drugs We never prescribe Schedule 1 drugs Schedules 3 and 4 have a lower abuse potential
Drug A is an inhibitor of CYP1A2. Drug B, a prodrug, is a substrate of this enzyme. What is the result on Drug B of the introduction of Drug A? A. Drug B will be more toxic because it is not metabolized as well. B. Drug B will have a weakened effect. C. Drug B will not become water-soluble D. This question cannot be answered based on the information provided
B Prodrugs need to be metabolized or they have no effect. So, if the enzyme is decreased, there is less active drug.
Referring to the same drug above (weak base that ionizes at <4). What will happen to its absorbability if the person takes omeprazole which raises the gastric pH to 5? A. The drug will only be absorbed in the small intestine because it is a weak base. B. The drug will be absorbed in the stomach and the small intestines. C. The drug will ionize in both stomach and small intestine thus increasing its total absorption. D. The drug will become a weak acid.
B The only that changes is that it is not ionized in the stomach so it can also be absorbed there as well as any other area with a pH of 4.
T/F: Schedule 1 drugs need a prescription to be called into a pharmacy.
False: schedule 1 can't be prescribed
The patient needs an antibiotic for his mycoplasma pneumonia. He is 84 yrs old and is frail and has had a past MI with a resultant right bundle branch block and atrial fbrillation. He is on warfarin to prevent stroke. Which medication below is your best choice for treatment of his pneumonia. A. clarithromycin B. trimethoprim /sulfamethoxazole C. third generation cephalosporin D. Amoxicillin
B You can't use any drug that will prolong the QT interval in a pt who already has a prolongation. Biaxin is not a good choice bc it will further prolong QT interval w/ warfarin. Since there is no cell wall in a mycoplasma, you cannot use any abx that's action is to destroy a cell wall. Other mechanism will work.
What term describes the drug level required for a medication to have a therapeutic effect in a patient? A. Dynamic equilibrium B. Critical concentration C. Selective toxicity D. Active transport
B - A critical concentration of a drug must be present before a reaction occurs within the cells to bring about the desired therapeutic effect - Also known as "minimal effective concentration"
A patient presents to the ER with a serum drug level of 50 g/mL. The half-life of this drug is 1 hour. With this drug, concentrations above 25 g/mL are considered toxic. How long will it take for the blood level to reach the non-toxic range? A. 30 minutes B. 1 hour C. 2 hours D. 3 hours
B - Half-life is the time required for the serum concentration of a drug to reduce by 50% - After 1 hour, the serum concentration would be 25 g/mL (which is no longer toxic)
You are reviewing an older patient's chart during a routine clinic visit. Which patient information is of most concern to you if they are on multiple protein-bound medications? A. Chronic constipation B. ow serum albumin C. Increased body fat D. Low serum creatinine
B - Low serum albumin reduces protein binding of drugs & can cause levels of free drug to rise, increasing risk of toxicity - The other options are not related to drug protein-binding
Your patient is taking drug A, a pro-drug that is a substrate for the CYPA12 enzyme. You start them on drug B, which is a strong inhibitor of CYPA12. What do you anticipate will happen? A. There will be no impact on levels of either drug B. The therapeutic efficacy of drug A will be significantly reduced C. The patient will be at risk for drug B toxicity D. The patient will be at risk for drug A toxicity
B - Remember that pro-drugs need to undergo metabolism in order to become "active" - So strong inhibition of CYPA12 for a prodrug means that drug A will have decreased activation, and therefore reduced therapeutic effects - It would be the opposite if it were a normal drug (not a prodrug) ... strong inhibition of CYPA12 would place patient at risk for drug A toxicity (because less of it would be broken down and excreted, so serum levels would be high)
A patient is taking 2 PO drugs, A and B. Drug A absorbs well in the small intestine, but is poorly absorbed in the stomach. Drug B absorbs well in the stomach, but is poorly absorbed in the intestines. What is likely true? A. Drug A is probably a weak acid and drug B is probably a weak base B. Drug A is probably a weak base and drug B is probably a weak acid C. Drug A is a weak base, but becomes an acid when in the stomach D. Drug B is a weak acid, but becomes a base when in the intestines
B Always remember that weak acids absorb well in the stomach & weak bases absorb well in the intestines (because they are not ionized in those body compartments)
A patient presents to your clinic complaining of vaginal itching after taking an antibiotic for the past 10 days. What is she likely experiencing? A. An adverse reaction from the antibiotic B. A superinfection caused by the antibiotic, which has destroyed normal flora C. An overdose of the drug that is damaging to more than one body system D. A drug toxicity effect of the antibiotic
B Superinfections often occur with antibiotic use (particularly with broad-spectrum antibiotics) because the drug kills off the normal bacterial flora in the body (i.e. in the gut, skin, vagina)
One aspect of promotion of positive outcomes is medication education. Identify the incorrect statement. (Ch. 3) A. Teach the patient purpose of the drug. B. Teach the patient where to purchase the drug. C. Teach the patient the dosing schedule. D. Teach the patient about adverse reactions.
B. Teach the pt where to purchase the drug
A blood pressure drug is small, lipid soluble with no charge at all times and is 99% protein bound. The patient's dose has been titrated and is at the appropriate dose maintain good control of his HTN. Recently, the patient begins to take daily high doses of an additional OTC drug that is also small, lipid soluble, carries no charge and is highly protein bound. Which of the following is likely to happen with the introduction of the second drug? A. The absorption of the blood pressure drug will increase because it is small, lipid soluble and has no charge B. The blood pressure drug will have decreased effectiveness. C. The patient will need to be monitored as he may become hypotensive. D. Since both drugs are small, lipid soluble and have no charge, the will compete with eachother at the same receptor sites on body tissues.
C If 1 protein-bound drug's dose is titrated for a specific effect, when you add another highly protein bound drug, both of them will compete for receptor sites on the albumin and more free (think active) drug will be in the plasma - this puts the person at risk for toxicity/OD from both drugs. These drugs have different actions and are not competing for the same receptor
The patient is being started on a medication which has an onset of 15 minutes, peaks at 2 hrs, half-life of 6 hours and a duration of 12 hrs. They are being given a loading dose which will get them into consistent therapeutic range in 2 hrs. When will steady state be acquired? A. 60 min B. 8 hrs C. 24 hrs D. 48 hrs
C Steady state is always 4 half-lives (4x6=24) - it cannot be changed by a loading dose, it is the time it takes for excretion to match the amount administered
A person with diabetes has a candida infection beneath her breasts and in her abdominal skin folds. Which of the antimicrobials is most appropriate treatment? A. oral metronidazole B. oral griseofulvin C. topical Nystatin- Mycostatin D. oral acyclovir
C This is a fungal infection so you can't use abx or antivirals. Topical antifungals are fine but oral griseofulvin does not treat yeast & it is wise to avoid systemic drugs if they can be avoided.
What kind of drug is vancomycin?
Glycopeptide antibiotic
GI/GU infections are usually caused by gram positive or gram negative organisms?
Gram negative (E. coli, Klebsiella, Proteus)
Skin infections are usually caused by gram positive or gram negative organisms?
Gram positive (staph, strep, candida)
Hepatic enzymes metabolize drug H making it water-soluble (this means it makes it a permanently charged form of the drug - it will no longer be re-absorbed). The drug is then carried in the plasma to the kidney where it passes through the glomerulus into Bowman's Capsule. What is the most likely result of these processes? A. The acidity of the urine will make it non-ionized and the drug will be re-absorbed back into the blood stream through tubular reabsorption. B. the drug will be picked up by active transport receptors in the blood vessels and secreted into the kidney tubules. C. the drug will pass into the kidney pelvis, ureters and into the bladder. D. the drug will return to the glomerulus and be carried into the efferent arteriole.
C This is not about a weak acid or weak base that changes forms. One of the actions of metabolism by the liver is to produce a charged (H2O soluble) form of the drug. Once the ionized drug exits the bloodstream through the glomerulus, it cannot go back through any tissues bc it has a charge. The only choice is excretion.
Which type of medication prescribed to a pregnant patient is more likely to have effects on the fetus? A. Drugs that are highly polar B. Ionized drugs C. Lipid-soluble drugs D. Protein-bound drugs
C - Lipid-soluble drugs cross the placenta more easily - Drugs that are highly polar, ionized, or are protein-bound will have more difficulty crossing
You are caring for a patient who overdosed on a barbiturate, which is a weak acid that ionizes at pH of 8 and higher. This drug will absorb in the ____________ and we can expedite elimination with use of _____________ to raise the urine pH. A. small intestine; bicarbonate B. blood; aspirin C. stomach; bicarbonate D. urine; aspirin
C - Weak acids absorb easily in the stomach where they are non-ionized - Bicarbonate is used to raise the urine pH & "trap" the drug, which forces excretion
A cancer patient is receiving morphine to treat their cancer-related pain. Approximately every 7 days, the medication is no longer effective in controlling her pain and a larger dose is needed to achieve the same effect. What is happening? A. Cumulation effect B. Drug interactions C. Drug tolerance D. Addiction
C The body may develop a tolerance to some drugs (like narcotics) when used chronically - When tolerance occurs, the same amount of the drug no longer causes the same reaction so higher doses are required to achieve a therapeutic effect
What is the safest drug category for pregnant women?
Category A
What is the contraindicated drug category for pregnant women?
Category X
A medication is a weak base that ionizes at a pH of 4 and lower. The medication is administered orally. Which of the following statements is accurate? A. It will be absorbed primarily in the stomach and become ionized once it reaches the small intestine. B. it will be absorbed primarily in the small intestine and become ionized once it reaches the blood stream. C. Whenever it becomes ionized, the drug will attach to an active transport receptor and be carried into the blood stream. D. It will be absorbed in the small intestine and be non-ionized in the blood stream and will be able to enter into a lactating woman's breast milk and also return to the bloodstream from the breast milk.
D It is a weak base so, in this case it is a non-ionized in any pH greater than 4 - so it will be absorbed in small intestines, stay ionized in blood (7.45-7.45) and also be able to enter breast milk; since breast milk is 7.1, it will not ionize there either; there are not transport receptors for just any drug and they would not be active transport bc it is not an up gradient situation.
An otherwise healthy 13 yr old presents with a minor bacterial skin infection. Think about what is the most likely bacterial cause an infection of the skin and what is known about the resistance of these organisms. You note that the appearance of the infection suggests it may be MRSA. You have done a culture that will be back in 3 days but feel that the infection should be treated with an antibiotic now. Which of the drugs below has the greatest chance of treating the organism without adverse side effects? A. a fluoroquinolone B. amoxicillin/ clavanulate C. dicloxacillin D. tetracycline E. vancomycin
D The most likely organism is staph aureus & 80% of staph makes beta-lactamase - so don't use anything w/ a beta-lactam ring that is easily detached or w/o a beta-lactamase inhibitor. If not for the MRSA, you could use Augmentin or the dicloxacillin but bc it appears to be MRSA, you cannot. The PBP receptor has changed & a beta-lactam ring will not fit. The fluoroquinolone should not be used in kids (a new FDA report in May 2016 recommends against use in anyone unless there is no other choice). You certainly do not want an IV med - that is inappropriate so do a med that does not work by breaking down the cell well. A tetracycline like doxycycline works well.
A patient has a localized skin infection, which is most likely caused by a gram positive cocci. Until the culture & sensitivity results are available, you plan to order a _________ -spectrum _________ drug. A. broad; systemic B. broad; topical C. narrow; systemic D. narrow; topical
D - Because this is a localized infection, a topical agent is recommended - And unless the infection is very serious, a narrow-spectrum antibiotic would be best (choose one with good gram positive coverage because that is what tends to grow on skin)
A 5-year old child presents to your primary care clinic and has gray teeth. When taking a medication history, you will ask about previous use of which group of antibiotics? A. PCN B. Cephalosporins C. Sulfonamids D. Tetracyclines
D - Tetracyclines cause discoloration of developing teeth in children, which is an adverse effect unique to this class of antibiotics - The other drugs listed here don't cause this effect
You are treating a patient who has been receiving an IM drug, but will transition to the PO route upon discharge. What is responsible for the increased dosage prescribed for the PO dose of this drug? A. Passive diffusion B. Glomerular filtration C. Active transport D. 1st pass effect
D - The 1st pass effect involves drugs that are absorbed from the GI tract directly into the portal venous system, which delivers the drug to the liver for biotransformation - A large percentage of the PO dose is usually destroyed & never reaches the systemic circulation or the tissues - This is why higher doses are needed for PO forms of a drug vs. IV or IM
Drugs do not metabolize the same way in all people. For what patient would you expect to see an alteration in drug metabolism for drugs you prescribe? A. A 35 year-old woman with cervical cancer B.A 41 year-old man with kidney stones C. A 62 year-old woman in acute renal failure D. A 50 year-old man with cirrhosis of the liver
D - The liver is the most important site for drug metabolism - If it isn't functioning effectively, drugs won't metabolize normally & toxic drug levels will develop without dose reductions
