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NURS 6521N Midterm Exam Study Guide Advanced Pharmacology
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NURS 6521N MIDTERM SUMMARY AND EXAM STUDYGUIDE
NURS 6521N MIDTERM EXAM
o 100-question Exam which will assess your knowledge on the Learning Resources from Weeks 1-6.
o Time limit of 2 hours.
o Multiple choice or multiple selection.
o Due on October 14, 2019 1:59:00 AM EDT.
Pharmacokinetics:
• Understand the implications of changing renal function on creatinine and drug dosing-
o Some drugs have special decreased doses or different dosing schedules for those with
renal impairment (renal dosing)
o For drugs that are toxic to the kidneys, a routine urinalysis and serum creatinine
or creatinine clearance should be done
o Renal excretion is significantly reduced at birth, so drugs primarily excreted by
the kidneys should be given in lower dosages or longer dosing intervals
o Kidney disease can reduce drug excretion, causing drugs to accumulate in the body
o In older adults, renal function is assessed by creatinine clearance, not serum creatinine
▪ Creatinine levels do not adequately reflect kidney function in older adults
because the source of serum creatinine—lean muscle mass—declines in
parallel with the decline in kidney function.
o Drug accumulation secondary to reduced renal excretion is the most important cause
of adverse drug reactions in older adults.
o Renal function should be assessed regularly when using drugs that are
eliminated primarily by the kidneys
• What is the impact of the following on drug levels and dosing:
▪ Cirrhosis- Liver disease can cause drugs to accumulate because the liver is
the major site for drug metabolism
▪ In patients with hepatic impairment, drug dosages need to be reduced
or discontinued to prevent drug toxicity
▪ Some drugs have special decreased doses or different dosing schedules for
those with hepatic impairment (hepatic dosing)
▪ Liver enzymes may need to be checked periodically for drugs that can cause
liver damage
o Protein binding-
▪ plasma albumin is the main protein that drugs can bind with
▪ drug binding to albumin is reversible making drugs bound and unbound( free)
▪ free means circulating in blood
▪ the percentage of drug molecules that are bound determines the strength of
the attraction between albumin and drug
,NURS 6521N MIDTERM SUMMARY AND EXAM STUDY
GUIDE
• Example- coumadin creates a strong bond causing 99% of the drug to
be bound and 1% to be free( unbound)
• Gentamycin and albumin creates a weak bond leaving 90% open
10% bound
• Consequences of bound drugs that they restrict the ability reach their
site of actions or are metabolized because albumin is to large leave the
bloodstream; once bind are broken the drug leaves the circulation.
• Albumin has minimal site that drugs can bind; drugs will compete for
the receptors to bind with may causing an increased intensity of
medication and depending on the medication cause toxicity
o Drug interactions-
Drugs produce effects by interacting with other chemicals( receptors) they produce the
effects of the drugs- it is usually reversible
The binding to the receptor either blocks or mimics or increase/decrease the physiological
activity of that receptor
Selectivity is the ability to elicit only the response for which a drug is given
The drug only reacts with one receptor type regulated a few processes and effects are
limited.
Receptors are like a lock and key only certain drugs bind to specific receptors
Simple occupancy theory
The intensity of the drug is proportional to the number of receptors occupied by that
drug
The maximal response will occur when all receptors have been
occupied Modified occupancy theory
Affinity refers to the strength of the attraction between drug and receptor
High affinity are strongly attracted to their receptors
low affinity is weakly attracted
Potency – causes a strong attraction to receptors drugs with high affinity can
bind with receptors when present in low concentration
Intrinsic activity refers the ability of the drug to activate the receptor after binding
Medications with high intrinsic activity have maximal efficacy
An intense receptor activation causes intense responses
▪
o Half-life- The actual amount of drug that is lost during one half-life depends on the
amount of the drug present in the body. Half-life refers to a percentage (50%), not an
amount.
,NURS 6521N MIDTERM SUMMARY AND EXAM STUDY
GUIDE
Example: Morphine has a half-life of 3 hours. This means that the drug level of morphine
will decrease by 50% every 3 hours, regardless of the amount in the body. If there are 50
mg of Morphine in the body, 25mg will be lost in 3 hours.
*The half-life of a drug determines the dosing interval. For drugs with a short half-life,
the dosing interval must be correspondingly short. If a long dosing interval is used for a
drug with a short half-life, drug levels will fall below the minimum effective
concentration (MEC) between doses, and therapeutic effects will be lost.
(MEC) =defined as the plasma drug level below which therapeutic effects will not occur.
o
Routes of Administration and Dosage Forms:
• Understand the different routes of administration and dosage forms and some of the
challenges and benefits associated with these routes and forms.-
IV- Barriers to absorption: none, absorption is instantaneous
Advantages: rapid onset, precise control over drug levels, permits use of large fluid
volumes/irritant drugs
Disadvantages: irreversible, expensive, inconvenient, not suited for self-administration, risk for fluid
overload, infection, and embolism, drug must be water soluble
IM- Barriers to absorption: Capillary wall, absorption is rapid with water soluble drugs and slow with
poorly soluble drugs
Advantages: permits use of poorly soluble drugs and depot preparations
Disadvantages: possible discomfort, inconvenient, potential for injury
subQ- Barriers to absorption: Capillary wall, absorption is rapid with water soluble drugs and slow
with poorly soluble drugs
Advantages: permits use of poorly soluble drugs and depot preparations
Disadvantages: possible discomfort, inconvenient, potential for injury
PO- Barriers to absorption: Epithelial lining of GI tract; capillary wall, absorption is slow and
variable
Advantages: easy, convenient, inexpensive, self-medication, potentially reversible, safer than
parenteral routes
Disadvantages: variability, gastric acid and digestive enzymes may inactivate some drugs, N/V from
local irritation, patient must be conscious and cooperative
Transdermal- Barriers to absorption: epidermis, dermis
Advantages: provide the highest medication absorption, prolonged duration of action, useful for
potent drugs, reduction of adverse effects
Disadvantages: possibility of irritation at the site of application, limitation on drugs that can be
delivered in this manner, creates increased risk for toxicity in infants
, NURS 6521N MIDTERM SUMMARY AND EXAM STUDY
GUIDE
Inhaled: Barriers to absorption: lung surfactant, surface lining fluid, epithelium, interstitium and
basement membrane and the endothelium.
Advantages: therapeutic effects are enhanced by delivering drugs directly to their site of action,
systemic effects are minimized, relief of acute attacks is rapid
Disadvantages: many variables can affect the dose of the drug delivered to the airways, determination
of the true dose is difficult, patients need professional guidance on the proper use of inhalation
devices, practitioners can be confused by the number of device types and the variability of use.
• Understand when it is OK to crush (or not crush) certain dosage forms and why.
There are multiple reasons for crushing tablets or capsule contents before administering medications,
but there are numerous medications that should not be crushed. These medications should not be
chewed, either, usually due to their specific formulations and their pharmacokinetic properties. Most
of the no-crush medications are sustained-release, oral-dosage formulas. The majority of
extended-release products should not be crushed or chewed, although there are some newer
slow-release tablet formulations available that are scored and can be divided or halved (e.g.,
Toprol XL).
A common reason for crushing a tablet or capsule is for use by a hospitalized patient with an enteral
feeding tube. A recent review in the American Journal of Health-System Pharmacy provides more
details about administering medications in patients with enteral feeding tubes. Oral solutions can be
used when commercially available and medically appropriate. If an oral solution or suspension
is not available, the hospital pharmacy should be consulted to determine if a liquid formulation
of the product can be extemporaneously prepared. In some cases, after careful consideration of
compatibility, stability, and drug absorption changes, an injectable formulation of a product may be
used.
Generally, meds that should not be crushed fall into one of these categories:
Sustained-release tablets, which can be composed of multiple layers for different drug release
times, as can beads within capsules. Some of the more common prefixes or suffixes for sustained-
release, controlled-release, or controlled-delivery products include: 12-hour, 24-hour, CC, CD, CR,
ER, LA, Retard, SA, Slo-, SR, XL, XR, or XT.
Enteric-coated tablets, which are formulated because certain drugs can be irritating to the
stomach or are degraded by stomach acid. By enteric-coating tablets or capsule beads, the drug’s
release can be delayed until it reaches the small intestine. Prefixes include EN- and EC-.
Other medications have objectionable tastes and are sugar-coated to improve tolerability. If this type
of medication is crushed, the patient would be subject to its unpleasant taste, which could
significantly impair medication adherence. Additionally, both sublingual and effervescent
medications should not be crushed because it will decrease the medication’s effectiveness.
• Which routes of administration have the fastest and slowest rates of absorption?
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