pharmacologic principles Flashcards
pharmacokinetics
what the body does to drugs
4 parts of pharmacokinetics
absorption
distribution
metabolism
excretion
pharmacodynamics
study of what drugs do to the body
pharmacodynamics target sites
receptors
ion channels
enzymes
carrier proteins
absorption
method and rate at which drugs leave the site of administration
distribution
occurs when the drug leaves the systemic circulation and enters the intersititium and cells
drugs are redistributed in organs according to their
fat and protein content
psychotropic drugs and fat/protein
most are lipophilic and highly protein bound
only unbound (free) portion is active
so low albumin levels like in malnutrition, aging etc, can experience toxicity due to inc free drug
older adults and psychotropic drugs based on fat/protein
if high fate to lean body mass, like older adults, could have erratic amounts of active drug in system
metabolism
process by which the drug becomes chemically altered in the body
first pass metabolism
process by which the drug is metabolized by CYP450 enzymes in the intestines and liver prior to going to the systemic circulation
elimination
process by which the drug is removed from the body
half life
time needed to clear 50% of the drug from the plasma
also determines the dosing interval and length of time to reach steady state
steady state
point at which the amount of drug eliminated between doses is approximately equal to the dose administered.
drugs usually administered once every half life to achieve steady state
takes about 5 half lives to achieve steady state and 5 to completely eliminate a drug
what can alter pharmacokinetics
p450 can induce or inhibit
10+ whites
20% asians
1st pass in some p450s
enzyme inducers and inhibitors
liver and kidney dz
CYP450 inhibitors
Buproprion
Clomipramine
Cimetidine
Clarithromycin Fluoroquinolones
Grapefruit
Ketoconazole
Nefazodone
SSRIs
CYP450 inducers
Carbamazepine
Hypericum (St. John’s Wort)
Phenytoin
Phenobarbital
Tobacco
types of pharmacodynamic receptor effects
agonist effect
inverse agonist effect
partial agonist effect
antagonist effect
agonist effect
drug bunds to receptors and activates a biological response
inverse agonist effect
drug causes the opposite effect of agonist, binds to same receptor
partial agonist effect
drug does not fully activate the receptors
antagonist effect
drug binds to receptor but does not activate a biological response
NTs and ion channels cause
excitatory or inhibitory response
excitatory response
depolarization
involves the opening of sodium and calcium channels so these ions can go into the cell
inhibitory response
repolarization
involves the opening of the chloride channels so chloride goes into the cell, potassium leaves, or both
drug actions and enzymes
important for metabolism and chemical alteration
ex: MAOI inhibit the action of a specific enzyme to inc availability of the NT
drug action and carrier proteins or reuptake pumps
they transport NTs out of the synapse and back
some drugs like SSRIs inhibit reuptake pumps to inc synaptic availability of the NT
potency
relative dose required to achieve certain effects
therapeutic index
ratio of median toxic dose to the median effective dose
so high index is safer because the therapeutic dose and toxic dose are far apart
tachyphylaxis
an acute dec in the therapeutic response
PMHNP pharma mgmt process
- make dx and identify target sx
- consider the phase (acute, relapse, recurrence)
- Assess pt and fam hx of rsponse to certain rx.
- Assess motivation and misgivings
- Identify poss drug drug interactions
- identify cultural implications
- Discuss risks and benefits
- Document informed consent and pt understanding of target sx, benefits, risks, and alternatives
- Monitor response and side effects.
Rx categories commonly used to tx schizophrenia and other psychotic disorders
typical antipsychotics
2nd gen antipsychotics
Rx categories commonly used to tx mood disorders and bipolar affective disorders
mood stabilizers
Rx categories commonly used to tx mood disorders, unipolar affective disorders and depressive disorders
TCAs
SSRIs
MAOIs
SNRIs and other agents
Rx categories commonly used to tx anxiety disorders
Benzos
anxiolytics
other agents like BBs
Rx categories commonly used to tx ADHD
stimulants
other agents
schedule 1 vs schedule 2 drugs
1 is nonmedicinal
2 is medicinal but still high abuse.
possible risks of taking psychotropic rx during pregnancy
problems with appetite
transient agitation or sedation
premature labor
drug d/c sx
teratogenic of some psychotropics
possible risks of NOT taking psychotropic rx during pregnancy
recurrence of sx
adverse effects on mother infant bonding
poor maternal self care
pregnancy and benzos
floppy baby
cleft palate
pregnancy and carbamazepine (tegretol)
NT defects
pregnancy and lithium
epstein anomaly
pregnancy and depakote
NT defect (spina bifida)
atrial septal defect
cleft palate
poss long term term dev deficits
common rx that can induce depression
BB
steroid
interferon
accutane
some retrovirals
antineoplastics
benzos
progesterone
common rx that can induce mania
steroids
antabuse
isoniazid
antidepressants in persons with bipolar disorder
false pos drug test for amphetamines
stimulants
wellbutrin
prozac
trazodone
ranitidine
nasal decongestants
pseudofed
false pos drug test for alcohol
valium
false pos drug test for benzo
sertraline (zoloft)
false pos drug test for cocaine
amoxicillin
most abx
NSAIDs
false pos drug test for heroin
quinolones
rifampin
codeine
poppy seeds
false pos drug test for methadone or PCP
OTC cough meds like nyquil, dextromethorphan
