Pharm A Test 1 Flashcards
(275 cards)
1
Q
Which subset of pharmacology deals with absorption, distribution, metabolism, and excretion
A
Pharmacokinetics
2
Q
What subset of pharmacology deals with intrinsic sensitive/responsiveness of the body’s receptors to a drug
A
Pharmacodynamics
3
Q
What type of receptor is a Beta adrenergic receptor
A
Membrane receptor
4
Q
What type of receptor is a GABA receptor
A
Ligand-gated ion channel
5
Q
What type of receptor regulates Na+ channels
A
Voltage-gated ion channels
6
Q
What is an example of a drug that blocks voltage-gated ion channels
A
Local anesthetics (Lidocaine)
7
Q
What is the definition of enantiomers
A
2 molecules with the same chemical composition but different orientations - mirror images
8
Q
What is a racemic mixture
A
When 2 enantiomers are present in equal proportion
9
Q
A drug that combines directly with its receptor to trigger a response is what type of agonist
A
Directly acting receptor agonist
10
Q
A drug that produces its physiologic response by increasing the concentration of endogenous substrate (NT or hormone) at receptor site is what type of agonist
A
Indirectly acting receptor agonist
11
Q
What type of agonist is phenylephrine
A
Direct - binds to alpha receptors and directly activates them
12
Q
What type of agonist is ephedrine
A
Indirect - evokes the release of norepinephrine from post synaptic nerve endings
13
Q
What type of antagonism can be overcome by increasing the agonist concentration at the receptor site
A
Competitive
14
Q
What type of antagonism cannot be overcome by agonists
A
Noncompetitive
15
Q
Is neostigmine a competitive or noncompetitive antagonist
A
Competitive
16
Q
What is a hyperactive response
A
An unusually low dose of drug triggers a pharmacological effect. Occurs in very sensitive patients
17
Q
What is a hypersensitive response
A
An allergic response to a drug
18
Q
What is a hyporeactive response
A
The patient requires larger doses for desired effect, often due to tolerance
19
Q
What is a tachyphylactic response
A
Decrease effectiveness of a drug with multiple doses
20
Q
What is an example of a drug with a tachyphylactic effect
A
Ephedrine
21
Q
What is an additive effect of drugs
A
A second drug administered with an initial drug with produce an effect equal to the sum of the 2 doses if administered independently
22
Q
What is a synergistic effect of drugs
A
2 drugs administered together may produce a greater effect than if they were given alone
23
Q
What is an example of 2 drugs, when given together, that will produce a synergistic effect on respiratory rate
A
Versed and fentanyl
24
Q
What is an antagonist effect of drugs
A
2 drugs administered together will have a lesser effect than either given alone
25
What is a prodrug
Pharmacologically inactive compounds designed to maximize the amount of active species that reaches its site of action. The metabolite has the clinical effect
26
How are drugs administered enterally
Via the alimentary tract
27
What are 3 examples of enteral routes of administration
Oral, rectal, sublingual
28
Which enteral route of administration is subject to first pass hepatic metabolism?
Oral, because drugs from GI enter the portal vein
29
What is an advantage of sublingual administration of drugs
Rapid absorption through buccal mucosa and bypasses the liver, dumps directly into SVC
30
What types of patients might require a drug to be administered rectally
Pediatric/uncooperative patients, patients who are vomiting
31
What are some examples of parenteral routes of administration
IV, IM, SC, pulmonary, intra-arterial, intrathecal, nasal, topical, transdermal
32
What is the difference between topical and transdermal routes of administration
Topical administration is for a local effect at the application site. Transdermal administration is for a systemic effect
33
What are 3 site-specific factors that affect absorption
1) Blood flow from the site
2) Surface area for absorption
3) Solubility of the drug at the site
34
Where does the majority of a drug stay if it has a small volume of distribution
In the plasma
35
How does a high volume of distribution affect the elimination half-life
The greater the Vd, the longer the half-life
36
What does it mean if a drug has a high volume of distribution
It indicates that the drug is extensively taken up by tissues
37
What is the Compartment Models Theory
The body is composed of multiple compartments having calculated volumes and we can examine the pharmacokinetics of drugs in terms of what compartments they travel to
38
Which compartment, central or peripheral, has a rapid uptake of drug
Central
39
What fluids and tissues are included in the central compartment
Intravascular fluids and highly perfused tissues like lungs, heart, brain, liver
40
What percentage of total cardiac output goes to the central compartment
75%
41
The central compartment makes up what percentage of body mass
10%
42
What tissues are included in the peripheral compartment
Less vascular tissues like fat bone, and inactive skeletal muscle
43
From which compartment are drugs eliminated
Central compartment
44
What is the basic concept of volume of distribution
The total approximation of all the compartments to which a drug goes. Relates the amount of drug in the body to the concentration in the blood
45
What is the "distribution phase" of drug metabolism
Immediately after administration, movement from central to peripheral compartments
46
What is the "elimination phase" of drug metabolism
More gradual, as drug is removed from circulation
47
What type of drugs does albumin carry
Acidic
48
Which protein carries basic drugs
Alpha-1-acid glycoproteins
49
How is degree of protein binding and volume of distribution related
They are inversely proportional
50
Do drugs cross membranes when they are bound or unbound
Unbound
51
How does ionization affect drug action?
Whether or not it exists predominately in an ionized vs nonionized state affects how well it permeates membranes
52
What 2 things determine the degree of ionization of a drug?
pKa of substrate, pH of surrounding fluid
53
Which form of drug, ionized or nonionized, is more lipid soluble
Nonionized form
54
When pKa and pH are identical, which form (ionized or nonionized) is the drug in?
It exists in both forms
55
Acidic drugs are highly ionized at ______ pH, while basic drugs are ionized at ____ pH
alkaline (high) pH, acidic (low) pH
56
What is ion trapping
If a membrane separates areas of 2 differing pHs, the nonionized portion of a drug diffuses and equilibrates but the ionized form doesn't
57
What occurs in Phase I of metabolic biotransformation
The drug is converted to a polar metabolite
58
What occurs in phase II of metabolic biotransformation
Conjugate with endogenous substrate to water soluble
59
What are the 4 major types of drug metabolism
Oxidation, reduction, conjugation, hydrolysis
60
What are 2 reactions that aid in the clearance of drugs from plasma
Ester hydrolysis, Hofmann elimination of cisatricurium
61
What are some signs of anxiety
Diaphoresis (sweating), hyperventilation, tachycardia
62
What is the onset time of IV midazolam
30-60 seconds
63
What is the peak time of IV midazolam
3-5minutes
64
What is the duration of IV midazolam
15-80 minutes
65
What is the trade name of Lorazepam
Ativan
66
What is the onset time of IV Lorazepam
1-2 minutes
67
What is the peak time of IV Lorazepam
20-30 minutes
68
What is the duration of IV Lorazepam
6-10 hours
69
What is the trade name of Diazepam
Valium
70
How is diazepam usually administered
Preop po
71
What is the half life of midazolam
1.9 hours
72
What is the half life of diazepam
43 hours
73
What is the half life of lorazepam
14 hours
74
Benzodiazepines are _____ soluble at a pH over 6
Lipid soluble
75
Benzodiazepines are ____ soluble at a pH below 6
Water soluble
76
What receptors are affected by benzodiazepines
GABAa
77
Where are most GABAa receptors located
Cerebral cortex
78
Binding of benzodiazepines to GABAa receptors cause what?
Hyper polarization of cell
79
What percentage of receptors are occupied by benzos to treat anxiolysis
20%
80
What percentage of receptors are occupied by benzos to cause sedation
30-50%
81
What percentage of receptors are occupied by benzos to cause unconsciousness
60%
82
What do benzodiazepines cause?
Sedation, hypnosis, anxiolysis, anticonvulsant, anterograde amnesia
83
What are the main clinical uses of benzos
Relief of anxiety, sedation and amnesia before procedures
84
What is the per kilo dose for preop midazolam in kids
0.5mg/kg
85
What is the max dose of midazolam in kids
15mg
86
Which route of administration causes 50% of the drug to be cleared by first pass metabolism?
PO (orally)
87
What 3 things determine the distribution of benzos
Lipid solubility, rapid redistribution from brain, volume of distribution
88
How does the volume of distribution in elderly and obese patients affect the pharmacokinetics of benzos
They have a larger volume of distribution so there may be a longer duration of action
89
What is the percentage of protein binding in benzo metabolism
90-98%
90
What molecule is a main player in the metabolism of benzos in the liver?
Cyt P450
91
How does alcohol affect the clearance of benzos
It increases clearance
92
How are benzo metabolites excreted
In the urine
93
How do benzos affect cerebral blood flow, cmro2, and MAC requirements
Decrease cmro2 and cbf, decrease MAC by 30%
94
How do benzos affect ventilation
Can have a dose dependent decrease
95
How do benzos affect BP and HR
Minor decrease in BP and increase in HR
96
How do benzos work as anti-convulsants?
Facilitate the actions of inhibitory GABA
97
What is the drug and dose that is effective to treat lidocaine toxicity, DTs, and status epilepticus
Diazepam 0.1mg/kg IV
98
Midazolam is __ times more potent than Valium (diazepam)
2-3x
99
What benzos can be used to treat insomnia
Oxazepam, flurazepam
100
What unwanted side effects can be caused by diazepam (valium) and lorazepam (ativan)
Thrombophlebitis and venous irritation
101
What drug is used as a reversal of benzos and what is the dose/max dose?
Flumazenil, 0.1-0.2 mg IV - up to 3mg
102
What types of patients should you try to avoid or limit giving benzos?
Elderly, obese, liver failure, acutely intoxicated or recovering alcoholics
103
What patients might require more benzos?
Chronic alcoholic
104
What barbiturate induction drug is used in electric convulsive therapy?
Methohexital
105
What is the trade name of methohexital
Brevital
106
What is the pH of thiopental?
10.5
107
Why does thiopental burn so bad upon injection?
Its pH is so much higher than blood
108
What would happen if you put thiopental in the same IV line with another drug such as fentanyl?
They would crystallize
109
How long will thiopental last at room temperature?
~24 hours
110
How does thiopental affect GABA receptors?
It binds to GABAa and enhances the inhibitory action of GABA in the CNS, which decreases neuronal activity
111
How does thiopental affect chloride channels?
Opens chloride channels and increases the time that they are open, prolonging the inhibitory effect of the GABA channel
112
How does thiopental affect the sympathetic nervous system?
Decreases sympathetic nerve signal transmission.
113
How does thiopental's lipid solubility affect the onset time?
It is very lipid soluble so it has a very quick onset
114
What percentage of thiopental is protein bound?
80%
115
How does thiopental's lipid solubility affect its uptake into the brain?
There is very quick uptake into the brain due to the high lipid solubility
116
How do people "wake up" from thiopental?
It is redistributed from the CNS into other tissues such as fat
117
What is the IV induction dose of thiopental?
3-5mg/kg
118
What is the onset time of thiopental?
30-40 seconds
119
What is the peak time of thiopental?
1 minute
120
What is the duration of thiopental?
5-8 minutes
121
How is thiopental metabolized?
Slowly by the liver
122
Does thiopental produce active metabolites?
No
123
How does thiopental affect elderly and patients with liver dysfunction?
It hangs around longer due to decreased blood flow to the liver
124
How is thiopental eliminated?
By the kidneys
125
Besides induction of anesthesia, what is another use for thiopental?
Treatment of increased intracranial pressure
126
What is focal ischemia?
When a blood clot or clamp has reduced flow to a certain area of the brain
127
What is global ischemia?
When blood flow to the entire brain is stopped, commonly caused by cardiac arrest
128
What is a normal cerebral perfusion pressure?
80-100mmHg
129
What is a normal intracranial pressure for a supine patient?
8-12mmHg
130
Approximately what percentage of cardiac output does the brain receive?
15%
131
What is the cerebral blood flow rate under normal circumstances?
50mL/100g/min
132
What percentage of cerebral blood flow goes to the gray matter of the brain?
80%
133
What percentage of cerebral blood flow goes to the white matter of the brain?
20%
134
What percentage of the brain's energy consumption is used to support electrophysiologic function?
60%
135
Suppression of cerebral metabolism causes what effect on cerebral blood flow?
A reduction in cerebral blood flow
136
What is the mean arterial range of cerebral blood flow?
65-150mmHg
137
What is the PaCO2 range of cerebral blood flow?
25-70mmHg
138
When PaO2 reduces to below __mmHg, CBF increases dramatically
60mmHg
139
How does temperature change affect cerebral blood flow?
Primarily by suppressing cerebral metabolism
140
What is one of the best things you can do to the brain if it is going to be ischemic during surgery?
Cool it down to reduce its metabolism and blood flow
141
What percentage of oxygen goes to maintaining neuronal electrical activity?
60%
142
What percentage of oxygen goes to maintaining cellular integrity of brain cells?
40%
143
How does PaCO2 affect cerebral blood flow?
PaCO2 varies DIRECTLY with arterial CO2 tension. High PaCO2 levels (hypercapnia) increases blood flow to the brain, low PaCO2 decreases blood flow to the brain
144
How do you calculate cerebral perfusion pressure (CPP)?
CPP=MAP-ICP (if no ICP, CVP can be used as substitute)
145
How does ICP therapy with thiopental affect the brain?
Decreases metabolic O2 requirements, decreases cerebral blood flow
146
What is the only induction drug that increases cerebral blood flow?
Ketamine
147
What type of ischemia is cerebral protection via thiopental useful for?
Focal ischemia
148
What surgeries benefit from cerebral protection from focal ischemia via thiopental?
Carotid endarterectomy, thoracic aneurysm resection, cerebral aneurysm clipping
149
What are the cardiovascular side effects of thiopental?
Decreased blood pressure, increased heart rate
150
What chemical does thiopental cause a release of?
Histamine
151
How does thiopental affect body temperature?
Decreases body temperature due to vasodilation
152
How does thiopental affect CMRO2?
Decreases CMRO2 (cerebral metabolic rate) by up to 55%
153
What are the 2 reasons not to use thiopental?
1) Causes hangover
| 2) Acute intermittent porphyria
154
What causes Acute Intermittent Porphyria?
A deficiency in the enzyme porphobilogen deaminase
155
What are the symptoms of Acute Intermittent Porphryia?
Chronic diffuse pain
156
Is methohexital more or less lipid soluble than thiopental? How does this affect its distribution?
More lipid soluble so it hangs around in the CNS longer than thiopental before it gets redistributed to peripheral compartments
157
What is the IV induction dose of methohexital?
1-1.5mg/kg
158
What is a common side effect of methohexital?
Hiccups
159
What component of propofol makes it burn upon injection?
Glycerol
160
What component of propofol supports bacterial growth?
Egg phosphatide
161
The shelf life of propofol depends on what component?
The amount/type of bacterial retardant
162
How does propofol work in the CNS?
Decreases the rate of dissociation of GABA from the receptor, thereby increasing the duration of the GABA-activated opening of the Cl- channel with resulting hyperpolarization of cell membranes
163
What is the onset time of propofol?
30 seconds
164
When is the peak effect of propofol?
90-100 seconds
165
What is the duration of propofol?
5-10 minutes
166
What is the distribution half life of propofol?
2-8 minutes
167
What is the half life of prolonged infusions of propofol?
40 minutes
168
How is propofol metabolized?
By the liver and some by the lungs
169
Does propofol cross the placenta?
Yes, but there are no deleterious side effects to the baby because they can distribute propofol as well
170
What percent decrease in propofol dosing should you consider for elderly patients?
25-50%
171
Why do elderly patients require a decrease in propofol dosing?
They have a smaller central distribution volume and decreased clearance
172
How does propofol affect memory?
Causes anterograde amnesia (forget everything from that point forward)
173
How does propofol affect the cardiovascular system?
Decreases blood pressure, increases heart rate
174
How does propofol affect the pulmonary system?
Big increase in propofol can cause a big drop in respiratory rate and tidal volume
175
How does propofol affect the hepatic/renal system?
Decreases blood flow to these systems
176
How does propofol affect hypoxic pulmonary vasoconstriction?
It remains in tact
177
What is a major side effect of propofol injection?
Pain on injection
178
What is the induction dose of propofol?
1-2.5mg/kg
179
What is the dosing rate of propofol for IV sedation?
25-100mcg/kg/min
180
What is the dosing rate of propofol for a general anesthetic TIVA?
100-200mcg/kg/min
181
What is the normal limit on how long you should run someone on a propofol infusion?
72 hrs, after that you worry about hyperlipidemia
182
How much propofol would be useful to treat PONV?
10-15mg
183
What is the dose of propofol for antipruritic (anti-itching) effects?
10mg
184
Other than induction, anti-itching and anti-emetic, what are other uses of propofol?
Anticonvulsant and treatment of bronchoconstriction
185
What is the solubility of etomidate in solution? In plasma?
Water soluble in solution, lipid soluble in plasma
186
What makes etomidate burn so badly?
It is made up of 35% glycerol
187
How does etomidate work in the CNS to induce anesthesia?
Depresses reticular activating systems and mimics the CNS inhibitory effects of GABA
188
What is the onset of etomidate?
30 seconds
189
When is the peak effect of etomidate?
1 minute
190
What is the duration of etomidate?
3-5 minutes
191
How protein bound is etomidate?
76-77%
192
What is the elimination half life of etomidate?
2.6 hours
193
In patients with what comorbidity would you want to decrease the dose of etomidate?
End stage liver failure b/c etomidate could have an exaggerated effect
194
How is etomidate metabolized?
Hydrolysis, hepatic enzymes
195
How is etomidate eliminated?
Water soluble metabolites are eliminated by the kidneys
196
How does etomidate affect cerebral blood flow and metabolism?
Decreases by 35-45%
197
How does etomidate affect an EEG? What patients should you be cautious with using it?
Increases excitatory spikes in an EEG, caution in seizure patients
198
What system of the body is etomidate known for keeping stable?
Cardiovascular
199
How does etomidate affect ventilation?
Patients maintain respiratory rate
200
What muscular side effect is caused by etomidate?
Myoclonus
201
What induction drug causes adrenocortical suppression?
Etomidate
202
Why does etomidate cause adrenocortical suppression?
It inhibits 11-beta hydroxylase enzyme
203
Besides myoclonus, burning, and cortisol depression - what are some other side effects of etomidate?
Nausea and hiccups
204
In what clinical situations would it be beneficial to use etomidate?
Challenging cardiac cases. hypovolemic trauma patients, and burn patients during mask ventilation
205
What is the non-barbiturate induction agent with analgesic effects?
Ketamine
206
What is the main neurologic effect of ketamine?
Emergence delerium
207
How does ketamine affect MAO?
Inhibits norepi uptake which is why blood pressure doesn't decrease
208
How does ketamine affect muscarinic receptors?
Slightly antagonizes
209
How does ketamine affect NMDA receptors?
Non-competitive antagonist to NMDA receptors
210
How does ketamine affect opioid receptors?
Slightly agonizes
211
What is the onset time of IV ketamine?
30 seconds
212
What is the onset time of IM ketamine?
3-4 minutes
213
What is the duration of IV ketamine?
5-10 minutes
214
What is the duration of IM ketamine?
12-25 minutes
215
What is the solubility of ketamine?
Lipid soluble
216
Is ketamine highly protein bound?
No, only 27%. there is a lot of free drug to bind to different receptors
217
What is the elimination time of ketamine?
2.5 hrs
218
How is ketamine metabolized?
By hepatic C450 enzymes
219
What is the active metabolite produced by ketamine metabolism?
Norketamine - builds up if you run an infusion of ketamine
220
How is ketamine eliminated?
Kidneys
221
What is the analgesic infusion dose of ketamine?
0.1-0.5mg/kg/hr
222
Is ketamine better for somatic or visceral pain?
Somatic
223
What receptors does ketamine bind to if used in an epidural/spinal?
Mu receptors
224
What is the IV induction dose of ketamine?
1-2mg/kg
225
What is the IM induction dose of ketamine?
4-8mg/kg
226
How does ketamine affect intracranial pressure?
Increases it by increasing cerebral blood flow and cerebral metabolism
227
How does ketamine affect EEG?
Has an excitatory effect on EEG
228
Should ketamine be used for burst suppression?
No b/c of the excitatory effects on the EEG
229
Should ketamine be used for SSEP?
Yes b/c it helps with the strength of the signal
230
How does ketamine affect ventilation?
No depression, until you get to very high end of IV doses
231
How does ketamine affect the airway?
Increased secretions, bronchodilation
232
How does ketamine affect the cardiovascular system?
Increases BP (mainly systolic), HR, CO
233
What are risk factors of emergence delirium with ketamine?
Patients over 15, females, high doses of ketamine, underlying personality disorder
234
What can prevent emergence delirium caused by ketamine?
Versed
235
What are some patients who would benefit from induction with ketamine?
Burn patients, children, asthmatics
236
What patients/surgeries should you NOT induce with ketamine?
1) Elevated ICP/cranial mass
2) Open eye injury
3) Heart disease
4) Vascular aneurysms
5) Psychotic disease
237
What is the IV induction dose of etomidate?
0.2-0.6mg/kg
238
What class of drug is dexmedetomidine?
Alpha 2 agonist
239
What properties does dexmedetomidine possess?
Anxiolytic, anesthetic, hypnotic, analgesic
240
What is the dosing of dexmedetomidine?
1mcg/kg over 10 minutes
241
What is the dosing of a dexmedetomidine infusion?
0.2-0.7mcg/kg/hr
242
What are the cardiovascular effects of dexmedetomidine?
Bradycardia and hypotension
243
Why should you not use ketamine on patients with a bad heart?
It is a myocardial depressant
244
How is flumazenil metabolized?
By hepatic enzymes. It is metabolized faster than benzos
245
What happens on the monitors after there has been a maximum reduction in cerebral blood flow and metabolism?
The EEG flatlines
246
What are the target channels of local anesthetics?
Voltage gated Na+ ion channels
247
What is the bacterial retardant in propofol?
Disodium edetate
248
What non-barbiturate induction drug causes hiccups?
Etomidate
249
What can you not mix midazolam with to make an oral preparation?
Grape fruit juice
250
What barbiturate induction drug could you use for burst suppression?
Thiopental
251
Which induction drug is metabolized by hydrolysis and hepatic enzymes?
Etomidate
252
What are 2 examples of a prodrug?
ACE inhibitors, insulin
253
What causes the difference in effect of the same drug administered PO vs. IV?
First pass metabolism
254
What does the absorption rate of drugs administered IM and SUBQ depend on?
Blood flow rate
255
What are examples of drugs given transdermally?
Nicotine and fentanyl patches
256
Which benzo is used for seizure suppression?
Diazepam
257
What is the dose of diazepam for seizure suppression?
0.1mg/kg
258
What is an example of a drug that requires an enzyme for drug/receptor interaction
Phosphodiesterase inhibitor - Milrinone
259
What barbiturate induction drug is supplied as an anhydrous powder and must be refrigerated before use?
Thiopental
260
What are normal CMRO2 (cerebral metabolic rate of oxygen) values?
3-3.5mL/100g/min
261
What is normal cerebral venous PO2?
32-44mmHg
262
What is normal cerebral venous SO2?
55-70%
263
Cerebral blood flow is tightly coupled to what?
Cerebral metabolism
264
What patients would you want to use propofol carefully with?
Patients with cardiovascular disease, sepsis, respiratory disease, increased ICP, hypovolemia, hyperlipidemia
265
What neuro surgery would you want to use propofol carefully in?
If they are seizure mapping in a patient with seizure disorder. The propofol's anticonvulsant properties could hinder the procedure
266
What induction drug should you NOT use if your patient is steroid depleted, on chronic steroids, or immunosuppressed?
Etomidate because it decreases circulating levels of cortisol
267
What monitor would become inactive if you tried to use it after administering ketamine?
BIS
268
What induction drug would be useful for patients who are on chronic opioids for pain?
Ketamine
269
Which induction drug does not have GABA effects?
Ketamine
270
What induction drug would you avoid in a patient with schitzophrenia?
Ketamine
271
What induction drug would you avoid in a patient with Addison's Disease?
Etomidate b/c they are immunosuppresed
272
What induction drug would be good for a patient with critical aortic stenosis?
Etomidate
273
What induction drug would be good for a patient with Down's syndrome?
Ketamine IM
274
What induction drug would be useful in a patient having a spinal fusion with MEP monitoring?
Ketamine
275
What induction drug would you avoid in an emergent cerebral aneurysm clipping with burst suppression needed?
Ketamine
