Pharmacotherapeutics - Exam 1 Flashcards
_______ is altered by individual’s diseases, environment, and other medications
Pharmacokinetics
What are the 4 keys to pharmacokinetics?
Metabolism
Elimination
Absorption
Distribution
Name some factors that influence medication absorption. Are they affected by age or diseases/medication?
Absorptive surface
gastric pH
splanchnic blood flow
GI tract motility
mostly NOT affected by age and GREATLY affected by certain diseases and medications
Reduction in normal ______ leads to decreased absorption of some meds. Name 3 in particular
active transport mechanisms
B12, calcium and iron
What are 3 age related changes that effect medication distribution.
reduced lean muscle mass
decreased total-body water content
decreased serum albumin
How does having a reduced lean muscle mass change how medication is distributed?
Results in increased adipose tissue
Increased volume of distribution for lipophilic drugs (ex. BZDs).
Results in lower serum levels and prolonged clearance rates
How does having decreased total- body water content change how medication is distributed?
Decreased volume of distribution for hydrophilic medications (Digoxin, lithium)
Results in higher serum levels
How does having decreased serum albumin content change how medication is distributed?
Results in increased “free” drug levels which leads to increase risk of SE’s when high protein binding drugs are used
Decreased serum albumin can be seen the elderly, name 2 other conditions in which you may also see decreased serum albumin
Can be seen in patients with poor nutritional states, impaired renal function, and many other chronic conditions
How does ages effect the CYP450 metabolism? Why?
reduces CYP450 metabolism
Due to age related decrease in hepatic blood flow and overall liver size
What happens when CYP450 enzyme is inhibited? Induced?
toxic accumulation of other drugs that require P450 for metabolism
rapid metabolism of P450 drugs leading to decreased efficacy
_____ is most common cause of altered pharmacokinetics in elderly patients
_____ and ____ decrease with age. Serum creatinine may be _____ in geriatric patients despite renal impairment due to loss in ______
Renal impairment
Tubular function
GFR
normal
muscle mass
When prescribe certain medications to the elderly, need to check ________.
T/F: You can have normal creatinine and abnormal CrCl.
creatinine clearance
True!!
**What is the Cockcroft-Gault formula for estimating creatinine clearance?
Define pharmacodynamics. How does it change with aging?
Defined as how a drug affects the body
Altered receptor affinity or numbers, postreceptor alterations, and/or impairment of homeostatic mechanisms
**Specifically, geriatric patients are more sensitive to _______. What can it result in?
CNS depressants
delirium, confusion, agitiation
(example in class was Benadryl)
Define polypharmacy
Defined as simultaneous use of multiple medications by a single patient (more than 5 meds)
What re the risks/complications of polypharmacy
Increased adverse drug reactions, drug-drug interactions, drug-disease interaction
Increase cost burden
Increase risk of hospitalizations
Decreased quality of life
Adherence
**What is an adverse drug reaction? Adverse drug event?
Unwanted effects of drugs at NORMAL DOSAGE AND USE!!
An injury/harm resulting from the use of a pharmacologic agent (adverse drug reactions fall into adverse drug events)
- unintentional overdose, withdrawal reaction
Hospitalization rates due to adverse drug events are approximately ____ higher in geriatric patients
4x
Adverse drug reactions are most often related to ______ and ________. _____and _____ are two common meds responsible for >60% of all medication-related hospitalizations
multiple medications
number of chronic illnesses present
Anticoagulants
hyperglycemics (insulin)
(inhibiting/inducing) the P450 system is MC. Give one example. Why?
Inhibition of the P450 system
verapamil (CCB) and atorvastatin
Inhibition of P450 slows metabolism of atorvastatin leading to toxic levels of statin → liver dysfunction, myalgias, rhabdomyolysi
What does induction of the P450 result in? What are 4 common medications?
Results in rapid clearance and decreased effectiveness of drugs that are metabolized by P450
rifampin, barbiturates, carbamazepine, phenytoin