Test 1 - modules 1 and 2 Flashcards
(219 cards)
1
Q
what is another term for peak concentration
A
Cmax
2
Q
What is another term for trough
A
Cmin
3
Q
Maintenance dose formula
A
dose needed to maintain a steady state concentration
MD = Css x CL MD = Css x Vd x Kel
vd = volume of distribution Css = steady state concentration kel = elimination rate constant
4
Q
What would be the equation for the steady state concentration if I administered a particular dose at this dosing interval
A
Css = 1.5(t1/2) x dose
All divided by
Vd x dose interval
volume of distribution
Css = steady state concentration
5
Q
loading dose equation
A
Ld= Co x Vd
Co = desired plasma concentration of drug Vd = volume of distribution
6
Q
is the EC50 =/not= to the ED50?
A
same thing -
Effective concentration where 50% of max effect
Effective dose where 50% of the max effect
7
Q
what is the difference between first-order kinetics and zero-order kinetics
A
in first order - constant fraction of drug is eliminated
This is where you have half-life calculated
in zero order kinetics. There is a constant amount of drug is eliminated. It does not matter how much you give (independent of concentration of drug)
8
Q
in first order kinetics on a non-log scale, what kind of line?
A
curved
9
Q
in first order kinetics on a log scale, what kind of line?
A
straight
10
Q
Is ASA a first order kinetic drug or a zero order kinetic drug
A
zero order
11
Q
Is Dilantin a first order kinetic drug or a zero order kinetic drug
A
zero order
12
Q
on a non-log scale, what kind of line for zero order kinetic drug
A
straight
13
Q
on a log scale, what kind of line for zero order kinetic drug
A
straight
14
Q
in first order kinetic drugs the rate of drug elimination per hour is _______ on drug concentration.
A
dependent
The more drug in the body, the more eliminated per hour
15
Q
in zero order kinetic drugs, the rate of drug elimination per hour is ______ of drug concentration.
A
independent
the same amount is eliminated per hour regardless of how much drug is in the body
16
Q
in zero order kinetic drugs Cp decreases ______ with time
A
linearly
17
Q
In first order kinetic drugs Cp decreases ______ with time
A
exponentially
18
Q
gentamycin
zero order or first order
A
first order
19
Q
Vancomycin
zero order or first order
A
first order
20
Q
Ethanol
zero order or first order
A
zero order
21
Q
phenytoin
zero order or first order
A
zero order
22
Q
what is pharmacodynamics
A
once the drug has arrived to its site of action what is the effect on the body
23
Q
formula for therapeutic index
A
IT = LD50/ED50
LD50 = lethal dose in 50 percent
ED - effective dose in 50%
24
Q
the higher the Therapeutic index, the _____ the drug
A
safer
25
2 drugs have the same active ingredients and are identical in strength or concentration, dosage form, route of administration and F (fraction making it - how much of the drug actually makes it to the body)
they have ______
Bioequivalence
26
Fraction of the drug that makes it to the body
bioavailability (F)
27
Dosage formulation influences rate of _____
dissolution
28
where are drugs metbolized
liver
intestines
kidneys
29
What is the purpose of drug metabolism
to make active (or) inactive metabolites
and to make drug molecules more water soluble for easier elimination
30
what class of meds are known to significantly inhibit the metabolism of simvastatin because of inhibition of CYP3A4
Protease inhibitors
31
what meds will increase the levels of Warfarin via (S-warfarin due to CYP2C9)?
Amiodarone
Metronidazole
TMP/SMX
Fluconazole
increases risk of bleeding
32
Phenytoin brand names
Dilantin
| Phenytek
33
Phenytoin are used for what type of seizures
primary generalized and partial seizures
34
what type of seizures does Phenytoin known to worsen
Absence
35
Dosage forms of Phenytoin
PO or IV (NO IM)
36
side effects for Phenytoin
Increase drugs associated with CYP3A4
Sedation and CNS depression
gingival hyperplasia (also Calcium channel blockers and Cyclosporine)
Hirsutism
coarsening of facial features
hyperglycemia
Hematologic effects
osteoporosis - due to reduction in Vit D
Rash (including DRESS) - drug reaction when eosinophils are high
Megaloblastic anemia - due to reduction in folate (macrocytosis)
Teratogenicity
37
labs to monitor for Phenytoin
```
albumin
uremia (BUN)
TSH
Total Phenytoin level
Free Phenytoin level
```
38
How does Phenytoin work
blocks Na+ channels associated with depolarization, repolarization and membrane stability.
so if you have rapid firing this is to help stop the seizure
39
cardiac problems in TCA overdose or when you combine TCA with phenytoin
widen QRS
ventricular tachydysrhythmias
cause seizures
40
if someone has overdosed on TCA, now seizing....what should you avoid
(any tox case with seizures...NEVER give...)
Phenytoin -
blocks NA channels
worsen the seizures and cardiac conduction
41
what is the prodrug of phenytoin
Fosphenytoin (Cerebyx)
42
Prodrug of phenytoin is different from phenytoin and can be given by what route
This can be given IM
does not contain propylene glycol
43
Caution for phenytoin and kinetics
phenytoin will go from first order kinetics to a zero order kinetics at higher doses. overall phenytoin is considered to follow non-linear kinetics
44
what is the max rate for phenytoin on the IV load and why?
15-20mg/kg rate at no more than 50mg/min due to the presence of propylene glycol causes hypotension and cardiac arrhythmias
45
Phenytoin dose adjustments are based on ____
levels
Cp < 7mg/L - increase dose by 100mg/d
Cp 7-12 mg/L: increase by 50mg/d
Cp >12 mg/L increase by 30mg/d or less
0.74 mg/kg will increase level by 1 ug/ml assuming you haven't reached the saturation point
46
Free fraction is what is pharmacologically ____
active
47
when you give fosphenytoin IM when can you check a phenytoin level?
IV?
4 hours
2 hours
48
Phenytoin toxic effects
| levels and effect
Total >20mg/L = nystagmus
>30mg/L = ataxia, increased seizures
>40mg/L = Lethargy, altered consciousness and coma
49
drug of choice for trigeminal neuralgia
Carbamazepine
50
what type of seizures will Carbamazepine treat?
Partial and secondarily generalized tonic-clonic seizures
51
what type of seizures will Carbamazepine make worse
absence or myoclonic
52
what type of mental health disorder will Carbamazepine also treat
Mood stabilizer for bipolar disorder (esp mixed or rapid cycling)
53
other names for Carbamazepine
Tegretol, Tegretol XR
Carbatrol
Epitol
Equetro
54
Mechanism of Action Carbamazepine
Blocks Na channels
partial agonist at the adenosine A2A and A2B receptors
55
Therapeutic range for Carbamazepine
4-12 mg/L
56
Phenytoin (Dilantin) level reference range (total)
10-20mg/L
57
Can pregnant women take Carbamazepine
no
58
what genetic problem Carbamazepine
HLA-B 1502 allele - > severe rash (Stevens-Johnson Syndrome or Toxic epidermal necrolysis (TEN) - they need to be sent to the burn ICU - seen mainly in patients of Asian descent (Specifically Han Chinese)
59
Side effects of Carbamazepine
Leukopenia - caution in pt with Bone marrow suppression
Aplastic anemia and agranulocytosis (BBW)
Hyponatremia - stimulates release of ADH (SIADH)
Drowsiness
Fatigue
Nystagmus
60
Oxcarbazepine is also called
Oxtellar XR
Trileptal
61
what drug interaction is important to note for oxcarbazepine
contains ethanol
| cannot take with flagyl or antibuse
62
what drugs mentioned cannot be taken with flagyl or antibuse
Oxcarbazepine (antiepileptic)
| ritonavir (HIV)
63
what is the indication for Oxcarbazepine?
Initial and/or adjunct therapy for partial seizures
64
MOA Oxcarbazepine
Structurally similar to carbamazepine
NOT a metabolite
Inhibit voltage sensitive Na+ channels and modulates activity of voltage activated calcium channels
65
pharmacokinetic difference between Oxcarbazepine and Carbamazepine
Oxcarbazepine is not metabolized by CYP450
but it does still induce CYP3A4
66
Oxcarbazepine and food
IR can be taken without regard to food
XR should be taken on an empty stomach (1 hr before or 2 hrs after food)
67
Pregnancy risk
Lactation risk
Oxcarbazepine
C
| L3
68
Oxcarbazepine side effects
```
Headache
dizziness
nystagmus
blurred vision
n/v
rash
hyponatremia
```
overall lower risk
69
Eslicarbazepine indications
partial -onset seizures adjunct therapy
70
MOA Eslicarbazepine
thought to be sodium channel blocker but unknown
71
Eslicarbazepine pharmacokinetic
Induces CYP3A4
| Inhibits CYP2C19 - problem if on plavix
72
Valproic Acid indications
Complex partial (mono or adjunct therapy)
Status epilepticus
Absence Seizures (alternative option for, not first line)
Bipolar Disorder
Migraine prophylaxis
Migraine abortive therapy
73
Valproic Acid Brand
Depakene and Stavzor - Caps/syrup
Depakote (enteric coated) - preferred due to the GI side effects
74
How does Valproic Acid work
Partially blocks Na currents
may increase GABA levels and its effects by inhibiting the degradation of GABA by inhibiting GABA-T enzyme on the brain
75
Reference range and Tox range for Valproic acid
Ref - 50-125 mg/L or mcg/mL
Toxicity starts between 150-200
76
Drug interactions with Valproic acid
Lamotrigine (lamictal) - inhibits metabolism - associated with a dose or concentration effect of skin reactions (Steven johnsons)
Phenytoin
phenobarbital
CBZ
Ethosuximide
AZT (zidovudine)
77
Valproic acid pregnancy and lactation
D - neural tube defects
L2
78
Side effects of Valproic Acid
GI is the most common - enteric coated will help
weight gain
hepatotoxicity
pancreatitis
tremors
thrombocytopenia
Teratogenicity - due to folate deficiency
Hyperammonemia (NH3) - consider L carnitine therapy (Carnitor) if this happens
- causes encephalopathy
79
how do you treat hyperammonemia from valproic acid
L carnitine therapy (Carnitor)
80
drug of choice for absence seizures
Ethosuximide (Zarontin)
81
mechanism of action for Ethosuximide (Zarontin)
blocks thalamic (T-type) Ca++ channels
82
reference range for Ethosuximide (Zarontin)
60-100mcg/ml (some go up to 125 mcg/ML
83
side effects for Ethosuximide (Zarontin)
Gastritis (primary)
fatigue
headache
neurologic (psychotic behavior)
Rash (SJS)
Leukopenia (check CBC periodically)
Lupus like syndrome
84
phenobarbital (luminal) indications
alternative for partial and generalized tonic clonic seizures
typically used as second line but may be preferred in pregnant women (cat B/D depending on manufacturer)
Avoid in absence seizures - can worsen like phenytoin
85
MOA phenobarbital (luminal)
enhances GABA via increase in cl channel opening and makes GABA work better
also decreases glutamate mediated excitation on AMPA
at higher concentrations may block Ca channels
86
herbal medicinals that work on GABA providing anti anxiety
GABA
Valerian root
Kava
87
phenobarbital (luminal) clinical issues
Inducer of CYP450 and UGT enzymes
main side effect is sedation
develop tolerance
88
Reference range phenobarbital (luminal)
desired
toxic
desired 15-40mg/L
| toxic >50mg/L
89
Primidone (Mysoline) metabolized to
PEMA (phenylethylmalonamide) by oxidation and phenobarbital
90
what supplement do pt need if on phenobarbital (luminal)
folic acid
91
what levels do you monitor for Primidone (Mysoline)
```
Primidone (8-12 ug/ml)
phenobarbital levels (15-30ug/ml)
```
92
dose adjustments for Primidone (Mysoline)
renal dose adjustment after CrCl <50ml/min - metabolites can accumulate
93
metabolism warning for Primidone (Mysoline)
CYP450 inducer
94
Primidone (Mysoline) side effects
```
CNS depression
Sedation
Confusion
Suicidal ideations
megaloblastic anemia due to lowering of RBC and CSF folate levels
```
Avoid in pregnancy - crosses placenta and lowers folic acid
95
Lamotrigine (Lamictal) approved for ....
adjunctive therapy in adults and children > 2 years with
Partial epilepsy refractory to other agents
Lamictal XR approved for once a day add on for primary generalized tonic clonic seizures
Lennox Gastaut (in children) seizures
Bipolar disorder
96
MOA Lamotrigine (Lamictal)
block voltage sensitive Na+ channels -> inhibition of glutamate and aspartate
97
what antiepileptic is available in ODT
Lamotrigine (Lamictal)
98
drug drug interactions Lamotrigine (Lamictal)
Valproate - inhibits Lamotrigine (Lamictal) metabolism. start dose at 25mg qod when added
Carbamazepine: induces Lamotrigine (Lamictal) metabolism
99
Side effects Lamotrigine (Lamictal)
nausea
diplopia
ataxia
Skin rash - typically occurs in first 8 weeks and can lead to SJS, peds seem to be risk - other risk are doses higher than recommended, rapid dose escalation, giving with valproic acid
100
Gabapentin (Neurontin) indications
Partial seizures
postherpetic neuralgia
off label diabetic neuropathy
post op pain
restless leg syndrome
hot flashes
101
MOA GAbapentin
water soluble anticonvulsant that is still able to penetrate BBB. Binds to amino acid carrier protein and elevates GABA levels (does this but not as much)
Binds to subunits of voltage-gated Ca++ channels (primary)
102
metabolism consideration for gabapentin
renal dosing (CrCl <60)
103
Pregabalin (Lyrica) indications
partial onset seizures (adjunct)
Pain associated with diabetic neruopathy, post SCI, post herpetic neuralgia, fibromyalgia
104
MOA Pregabalin (Lyrica)
same as gabapentin but 3 xs more potent (I give less to have same pharm effect)
105
max dose of Gabapentin vs Pregabalin
3600mg/day
vs
600mg/day
106
metabolism consideration for Pregabalin (Lyrica)
renal dosing (CrCl <60)
107
side effects Pregabalin (Lyrica)
```
edema
sedation
dizziness
blurred vision
weight gain
```
108
Felbamate (Felbatol) used for
not first line agent
| used in Lennox-Gastaut
109
side effects Felbamate (Felbatol)
```
Aplastic anemia (within first 6 mos)
n/v
```
110
Tiagabine (Gabitril) indication
Partial seizures (adjunct)
111
Mechanism Tiagabine (Gabitril)
enhance activity of GABA by inhibition of neuronal uptake
112
metabolism considerations Tiagabine (Gabitril)
no renal or hepatic dosing
major substrate of CYP3A4
- clearance increased if used with carbamazepine and phenytoin
113
side effects Tiagabine (Gabitril)
Dizziness
drowsiness
difficulty concentrating
weakness
114
Topiramate (Topamax) indications
epilepsy (adjunct and monotherapy)
migraine prophylaxis
essential tremor and cluster headache prophylaxis
115
MOA Topiramate (Topamax)
inhibit Na channels, enhance GABA and antagonize glutamate receptors
116
dose difference in Topiramate (Topamax)
renal dose reductions occur for CrCl <70 ml/min instead of 60
117
drug interactions Topiramate (Topamax)
weak inhibitor of CYP2C19
118
side effect of Topiramate (Topamax)
weight loss
ataxia
impaired concentration
Acute angle closure glaucoma
Metabolic acidosis due to reduction in bicarbonate
Nephrolithiasis
Hyperammonemia
Pregnancy Cat D
119
Lacosamide (Vimpat) indications
adjunct partial onset seizures with epilepsy age>17 years (available IV and PO)
120
dosing considerations Lacosamide (Vimpat)
hepatic disease or CrCl <=30 then max daily dose is 300mg instead of 400
121
side effects Lacosamide (Vimpat)
increased SI
dizziness
ataxia
DRESS ( drug reaction with eosinophilia and systemic symptoms)
PR interval prolongation
122
Drug interactions Lacosamide (Vimpat)
Substrate CYP2C19
123
pregnancy risk Lacosamide (Vimpat)
C
124
Levetiracetam (Keppra) indications
partial seizures
tonic clonic
myoclonic
status epilepticus (off label)
125
MOA Levetiracetam (Keppra)
inihibit voltage dependent N type Ca++ channels
Facilitate GABA ergic inhibitory transmission by displacing negative modulators
binding to synaptic vesicle proteins 2A ligand (SV2A) that affect neurotransmitter release
126
dosing Levetiracetam (Keppra)
reduce dose once CrCl <80mL/min
127
Side effects of Levetiracetam (Keppra)
behavior problems (shows up in preexisting neuropsychiatric conditions)
weakness
n/v
headache
128
Brivaracetam (Briviact) works on
partial seizures
129
Vigabatrin (Sabril) indications
monotherapy for infantile spasms
add on to adults with partial complex seizures refractory to other anticonvulsants
130
why does Vigabatrin (Sabril) have strict access
toxicity to retina
(irreversible concentric peripheral visual field deficits) associated with retinal dysfunction
SHARE program
requires vision testing baseline and testing every 3 months
131
MOA Vigabatrin (Sabril)
thought to be related to being an irreversible inhibitor of GABA -T which is responsible for the metabolism of GABA
132
Vigabatrin (Sabril) drug interactions
Inducer of CYP2C9
can lower levels of phenytoin (Dilantin)
increase clonazepam through unknown mechanism
preg risk C
133
Zonisamide (Zonegran)indication
adjunct therapy in adults with partial seizures
134
Mechanism of Zonisamide (Zonegran)
blockade of Na and CA
135
Side effects Zonisamide (Zonegran)
dizziness and drowsiness
Hyperthermia (heat stroke in children)
Nephrolithiasis (encourage hydration)
136
drug interaction Zonisamide (Zonegran)
dont take with Sulfonamide allergy
Substrate CYP2C19 and 3A4
137
Perampanel (Fycompa) indication
Partial seizure and generalized tonic clonic
138
Perampanel (Fycompa) metabolism
Avoid if CrCl <30ml/min
major substrate of CYP3A4
139
Black box warning Perampanel (Fycompa)
dose related serious and life threatening psychiatric events - aggression, anger, HI, hostility in the first 6 wks of use
140
Rufinamide (Banzel) indication
Lennox-Gastaut syndrome
141
notes on Rufinamide (Banzel)
weak inhibitor of CYP2E1 and weak inducer of CYP3A4
known to cause dose related shortening the QT interval
142
what drugs inhibit Na channels
| anticonvulsant
```
Carbamazepine
Eslicarbazepine
Lamotrigine
Lacosamide
OxCBZ
Phenytoin
Rufinamide
```
143
what drugs increase GABA activity (anticonvulsant)
```
Benzodiazepine
Phenobarbital
Primidone
Tiagabine
Vigabatrin
```
144
What anticonvulsant drugs work on synaptic vesicle protein 2A ligand
Brivaracetam
| Levetiracetam
145
what anticonvulsant drugs work on inhibit Na and Ca channels
Zonisamide
146
what anticonvulsants inhibit Na channels and increase GABA levels
Topiramate
| Valproic acid
147
What anticonvulsants decrease glutamate
Felbamate
| Perampanel
148
non-opioid cox 3 inhibitor
Acetaminophen
149
max daily dose for tylenol
4,000mg/d however some limit to 3,000mg/d
150
Iv formulation of tylenol is approved for what age
2 yrs and older
151
antidote for acetaminophen tox
N-acetylcysteine (mucomyst; acetadote) best if given within 8-10 hrs of APAP ingestion/overdose
152
what organ does acetaminophen overdose effect
liver
153
opioid analgesics are all prototypes of
heroin
154
the net effect of opioid analgesics
a reduction in the ascending pathways for pain stimuli
155
opioid poisoning symptoms
```
coma
pinpoint pupils
respiratory depression (apnea)
```
156
Oxygenation vs ventilation
Oxygenating is inhaling (oxygenating)
ventilation is exhaling (blowing off Co2)
157
symptoms for opioid sedation
confusion with lack of rest from inadequate pain control
change dose
Can consider stimulant in certain patients
158
Resp depression from opioid overdose - antidote
Narcan
159
Rapid Sequence intubation
Pre-oxygenation (3-5 min at 100% O2)
cricoid pressure
sedative
paralytic
intubate
post intubation sedation
160
what drug class for Dexmedetomidine (precedex)
Sedative/hypnotic
selective CNS A-2 agonist
161
what sedative is used in ICU for weaning off ventilator since it doesn't depress resp drive
Dexmedetomidine (precedex)
162
Autoimmune destruction of the beta-cell thereby leading to absolute insulin deficiency
type I DM
163
A metabolic disorder resulting from the body's inability to make enough or properly use insulin
Type II DM
164
when would a hypothyroid pregnant woman need a dose increase
1st trimester
165
thyroid gland primarily secretes what?
T4
166
the most potent form of the thyroid hormone on metabolic influence is ____ is primarily derived by ____ being converted to ___ at the tissue level
T3
| T4->T3
167
It takes about _____ weeks for the TSH to reach steady state after changes in the T4/T3
6-7 weeks
168
TSH low
| T4 WNL
subclinical hyperthyroidism
| usually asymptomatic
169
Low TSH
| High T4
Overt hyperthyroidism
| symptomatic
170
Very low TSH
| Very high T4
thyroid storm
| hyperadrenergic state
171
high TSH
| High T4
secondary hyperthyroidism
| usually tumor from pituitary
172
excess thyroid hormone with thyroid storm being the more extreme presentation of hyperthyroidism
thyrotoxicosis
173
what herb can cause increase TSH secretions via thyroiditis
St. Johns Wort
174
what drugs can increase TSH secretion/release via thyroiditis
Amiodarone
Amphetamine
metoclopromide
175
what drugs increase T4/T3 synthesis
Amiodarone
| Iodine ingestion
176
What drugs increase T4/T3 free fraction (inhibit protein binding)
```
ASA
carbamazepine
heparin
lasix
NSAID
phenytoin
```
177
if a pt with hyperthyroidism develops fever what would you NOT give because it can make it worse
ASA
NSAID
they increase T4/T3 free fraction (inhibits protein binding)
making them more hyperthyroid
178
```
Anxiety
nervousness
dyspnea
weight loss
heat intolerance
N/V
menstrual irregularities
weakness (proximal muscles and pelvic girdle)
```
```
Agitation
Tachycardia +- a-fib
tremor
fever
diffuse goiter
ophthalmopathy
lid retraction or lag
```
Hyperthyroidism
179
if someone presents with A-fib, what should you check for
Hyperthyroidism
180
Hyperthyroidism management
Assumes no thyroitoxicosis or thyroid storm
Thioamides (meds)
Thyroidectomy
Thyroid replacement therapy
181
Meds for Hyperthyroidism
Methimazole (MMI) (Tapazole) - basically stop synthesis of T4/T3 in the thyroid gland - dosing initially high (30-60mg daily divided into 3 doses for an adult then taper to 5-15mg daily single dose...half life is 6 hours) - not protein bound - so always working bc not protein bound with long half life. Not good for a breastfeeding mom due to no protein binding. liver tox
Agranulocytosis - side effects. No in pregnancy
Propylthiouracil (PTU) -> Half life 1-2 hours
adults give 300-400mg/day in 3 divided doses then taper to 100-150mg/day in divided doses. 60-80% protein bound so technically better for breastfeeding. However, still not good bc it will still get into milk and your newborn needs those thyroid hormones. liver tox, Agranulocytosis - side effects. no in pregnancy
meds are only used in the interim until definitive treatment for hyperthyroid state
182
Thyrotoxicosis not yet decompensated symptoms
Weakness
weight loss
palpitations
still functioning
183
Decompensated thyrotoxicosis symptoms
fever
tachycardia
tremors
184
CV effects of thyrotoxicosis
Sinus tachycardia (most common)
A-fib (2nd most common)
Reduced filling times ->high output heart failure
185
what do you use to diagnose thyroid storm
and what tool?
clinical diagnosis
Burch & Wartofsky tool
- Thermoregulatory dysfunction
- CNS effects
- GI-hepatic dysfunction
- CV system
score -
<25 unlikely
25-44 - suggestive of impending storm
>45 - highly suggestive
186
Thyroid workup
Labs - TSH, T4, T3
T3 resin uptake
-assess thyroxine binding globulin levels ->if high means, TBG levels are low
+/- thyroid-stimulating antibodies
CXR
ECG
Differentials:
-Infection, heat exhaustion/stroke, delirium tremens (alcohol withdrawal), malignant hyperthermia, neuroleptic malignant syndrome, pheochromocytoma, cocaine, amphetamine ingestion
187
Steps in managing thyroid storm
Supportive care - oxygenation (metabolic demand is increased - may need oxygen), fluid resuscitation - if glucose is low use D5NS due to glycogen depletion, temp control (no NSAID or ASA) - ONLY Tylenol
Inhibit new hormone synthesis - usually PTU (this is because it also inhibits T4-T3), can also use Methimazole.
inhibit thyroid secretion - be careful - give the methimazole and PTU first so it can get into the gland. Then you give SSKI (super saturated potassium iodide) - possible to increase but when you give this large of a dose it should inhibit. if pt has iodine allergy- lithium carbonate
Dopamine, Octreotide and steroids
inhibit T4-T3 peripheral conversion (T3 is more potent and biologically active) - PTU, propranolol will also do this
Dexamethasone, Hydrocortisone
inhibit Beta receptors - causing tachycardia and hypertension - propranolol most commonly studied but overall a Beta blocker. Propranolol used frequently bc it also inhibits T4->T3 conversion (also decrease pulse, increase ventricular filling, decreases high output HF)
Thyroid hormone removal - cholestyramine binds enterohepatic reabsorption of thyroxine (can also use plasmapheresis, charcoal hemoperfusion, plasma exchange)
definitive treatment
- Radioactive iodide
- Surgery
188
what drugs used in thyroid storm treatment block TSH release
Octreotide
Steroids
Dopamine
189
What drugs used in thyroid storm work on thyroid hormone production
Methimazole
| Propylthiouracil
190
what drugs use in thyroid storm work on thyroid gland activity
Iodine or SSKI
| Propylthiouracil
Propranolol
Steroids
these 3 also help with preventing T4-T3
191
what thyroid lab can you not rely on and why
TSH, takes 6-7 weeks for T3/T4 to effect this number
192
when you are looking at thyroid storm, what should you consider
differential diagnoses
especially sepsis
193
In hyperthyroid, caution with giving ____ in failing to recognize high output heart failure
diuretics
194
Wait at least _____ after thioamide before giving high dose iodine
1 hour
195
dispo for thyroid storm
Admit to ICU
| may take 1-2 weeks to completely recover
196
TSH high
subclinical Hypothroidism
197
TSH high
| T4 low
overt hypothyroidism
| symptomatic
198
TSH VERY HIGH
| T4 VERY low
Myxedema coma
199
Myxedema coma is more common in who?
women >60yrs old
200
TSH low
| T4 low
secondary hypothyroidism
may be hypothalamus-pituitary axis problem or
sick euthyroid syndrome
201
autoimmune hypothyroidism
Hashimoto's Thyroiditis
202
drugs that decrease TSH secretion
Dopamine
Glucocorticoids
Octreotide
Opiates
203
Drugs that decrease T4/T3 synthesis
Amiodarone
Lithium
Methimazole (MMI)
Propylthiouracil (PTU)
204
Drugs that decrease T4/T3 secretion
Amiodarone
Lithium
SSKI
205
```
Fatigue
weight gain
depression
constipation
shortness of breath
cold intolerance
infertility
```
```
Macroglossia
periorbital puffiness
hoarseness
decreased bowel sounds
dry skin
delayed relaxation of ankle jerks
```
Hypothyroidism
206
Myxedema coma symptoms
```
AMS
bradycardia
hypotension
hypoventilation
hypothermia
```
metabolic and multi organ dysfunction
207
what can precipitate myxedema coma
uncorrected hypothyroidism or noncompliance
Infection
trauma
MI
HF
CVA
metabolic problems
208
Myxedema Coma diagnosis
hypothyroid based on labs (TSH may not be accurate)
Myxedema coma/crisis is a clinical diagnosis
209
labs for Myxedema
TSH
T4/T3
cortisol level (can be +/-)
BMP - risk of hyponatremia due to increase ADH and risk of hypoglycemia due to decreased gluconeogenesis, decreased insulin clearance and +/- adrenal insufficiency
VBG/ABG - metabolic & resp acidosis - d/t hypotension, hypoventilation, tissue hypoxia
210
managing hypothyroidism
```
synthetic T4 (levothyroxine) - gets converted to T3 by the body
-99% protein bound
-half life depends on thyroid status (euthyroid = 6-7 days, hypothyroid=9-10 days, Hyperthyroid =3-4 days)
(pregnant patients have dose increase in 1st trimester)
```
211
what factor needs to be taken into consideration when giving levothyroxine for hypothyroidism (pt history)
Cardiovascular disease
If <50 and with or without CVD = 1.6mcg/kg
If > 50 +/- CVD = 12.5-25mcg daily (more conservative approach - too much thyroid hormone can cause sinus tachycardia which can be bad on a diseased heart. This can cause A-fib - could cause a stroke)
212
Bioavailability of levothyroxine is higher on a empty or full stomach?
empty (however the most important is that they are consistent)
213
drug interactions with levothyroxine
Decrease Absorption -
-Di- and Tri- valent cations will reduce absorption (Al, Ca, Fe, Mg)
- Cholestyramine (Questran) - can bind to it.
- Sucralfate (carafate) - can chelate with charges
- Fiber supplements - increases peristalsis so transit time changes
Increase Clearance (enzyme inducers)
- Rifampin
- Carbamazepine
- Phenobarbital
- Phenytoin
214
If you have to change manufacturer for Levothyroxine what do you need to do
re-check TSH, T3, T4 in 6-7 weeks to see if they need dose adjustments
215
If not able to make T3 in the periphery, what med
Desiccated thyroid (Armour thyroid, Westhroid) (animal brain)
-seen in Congenital hypothyroidism
these are fixed doses of T4 and T3
216
Liotrix (Thyrolar)
another T4/T3 replacement
Congenital hypothyroidism
not animal sourced
217
Liothyronine indications
T3 therapy
```
Hypothyroidism (congenital)
Myxedema
Myxedema coma
cadaveric organ recovery
antidepressant augmentation
```
218
myxedema coma management
ABC support
Dextrose for hypoglycemia
Free water restriction for hyponatremia
Vasopressors (treat hypotension first with fluids)
Passive warming for hypothermia
Glucocorticoid replacement for stress
IV synthetic T4 (levothyroxine) (onset is 6-8 hours) - don't wait for labs - high morbidity rate
if initial dose T4 fails, give T3
219
what happens in pregnancy that a hypothyroid pt needs a dose adjustment
the increase in estrogen increases the thyroid binding globulin secondary to a reduction in its catabolism -> leads to an increase in T4 (bound and free) and T3. Since there is an increase in both, the free fraction and TSH is normal in a euthyroid patient. -> not the case in someone who gets pregnant - need large dose increase in thyroid replacement to avoid problems
