Pharmacology Flashcards
Treatment for methemoglobinemia in G6PD deficient patient?
Ascorbic acid because methylene blue uses the hexose phosphate pathway which is dysfunctional and will cause red blood cell lysis
Drug of choice in WPW?
stable rhythm: procainamide
unstable rhythm: cardioversion
Sugammadex dose for 2 twitches observed with TOF stimulation?
2 mg/kg
Sugammadex dose for 1-2 post titanic counts and NO twitches with TOF stimulation?
4 mg/kg
Sugammadex dose for immediate reversal after 1.2 mg/kg of rocuronium?
16 mg/kg
Side effects of Gabapentin?
nausea, sedation, dizziness, ataxia, nystagmus, peripheral EDEMA, and weight gain.
Mechanism of action of gabapentin
Binds alpha2-delta subunit of L-type voltage gated CALCIUM channels –> decreased NMDA release of excitatory GLUTAMATE from dorsal root ganglia
Triptan drugs are effective in migraine pain relief via agonism of which receptors? Contraindicated in which population?
5-hydroxytryptamine serotonin (5HT 1B/1D) agonism —> vasoconstriction of cerebral vessels > coronary vessels
Contraindicated in cardiac disease
Triptan drugs also target the trigeminal ganglion.
where does aprepitant antagonize substance P neurokinin 1 receptors?
in the brain stem - in the nucleus tractus solitarius that is ventral to the area postrema; works best in combination with 5HT3 antagonist dolasetron or a corticosteroid dexamethasone.
Effects of an acute dose of cannabis in a NAIVE user?
Tachycardia*
Systolic hypertension*
Malignant arrhythmias (afib, vfib, v-tach, brugada pattern)
Coronary spasm if previous CAD
Cerebral vasodilation and increased cerebral blood flow*
Airway hyperreactivity or upper airway obstruction (uvulitis)
Effects of acute dose of cannabis in a CHRONIC user (THC > or = 10 mg)?
Bradycardia –> tachycardia
postural/orthostatic hypotension
sinus arrest
airway hyperreactivity
Altered thermoregulation = intraoperative hypothermia –> postop shivering
coronary vasospasm/MI
cerebral vasospasm –> ischemic stroke (posterior circulation affected in 50%)
Primary pharmacological effect of magnesium on the neuromuscular junction?
Inhibition of CALCIUM-mediated RELEASE of acetylcholine from the PRESYNAPTIC membrane
Other minor effects: reduced muscle membrane excitability and inhibition of postjunctional potentials
Opioids to use in a CYP2D6 poor metabolizer?
hydromorphone, morphine, and oxymorphone are NOT metabolized through CYP2D6
How is PR interval affected by hypocalcemia, hypokalemia or hypomagnesium?
Shortened PR interval
**Hypokalemia and hypomagnesium are risk factors for atrial fibrillation
How is PR interval affected by hypercalcemia, hyperkalemia and hypermagnesium?
Prolonged PR
“HyPeR”
QRS complex change with hypokalemia or hypomagnesiumia?
Narrowed QRS
QRS complex change with hyperkalemia or hypermagnesiumia?
Widened QRS
QT interval changes with DECREASED calcium, potassium, or magnesium?
Long QT
QT interval changes with hypercalcemia?
Short QT
T-wave changes with hypocalcemia?
T-wave inversion
T-wave changes with hypercalcemia or hyperkalemia?
Peaked T-waves
Things that enhance the response to non depolarizing NMBDs versus things that diminish the response?
Enhanced (4 As): Volatile anesthetics, local anesthetics, anti-arrhythmics, and aminoglycosides.
Diminished response: steroids, calcium, and phenytoin
Drugs to avoid in assisted reproductive therapy?
Droperidol and metoclopramide due to increased prolactin levels which impairs follicle maturation and corpus luteum function.
Commercially prepared local anesthetic solutions with epinephrine differ from local anesthetic with freshly added epinephrine in what way?
“Pre-mixed” solutions have a lower pH –> more ionized so does not cross lipid membrane easily –> increased onset time
mode of delivery for calcium chloride versus calcium gluconate?
calcium chloride: give centrally
calcium gluconate: give peripherally
Amount of bicarb required to correct metabolic acidosis
sodium bicarb = 0.2 * kg * base deficit
Which type of toxicity is associated with cyclosporine and tacrolimus?
nephrotoxicity
Which type of toxicity is associated with methotrexate?
myelosuppression; also “LFTs” liver toxicity, pulmonary fibrosis, and thyroid
Which type of toxicity is associated with doxorubicin/daunorubicin?
Cardiac toxicicity
A type I protamine reaction is mediated by?
mast cell degranulation and histamine release caused by the polycationic structure of protamine during rapid administration –> systemic hypotension
A type II protamine reaction is mediated by?
IgE mediated anaphylaxis – prior exposure to protamine or similar protein necessary
A type III protamine reaction is mediated by?
thromboxane A2 released by platelets - pulmonary hypertensive crisis leading to right heart failure
first line treatment for neuropathy? second line?
1st line: TCAs, SNRIs, gabapentin, and pregabalin
2nd line: tramadol, capsaicin patches, and lidocaine patches
Which non-depolarizer to avoid in renal failure?
Vecuronium because of the active metabolite, 3-desaceryl-vecuronium – has 80% of the potency of vecuronium and can significantly prolong DOA in renal failure
Recent study with ketamine vs. saline placebo did not show a difference in the rate of ________?
Delirium
However patients were more likely to experience nightmares and hallucinations than the placebo group, especially with higher doses of ketamine.
Presumed mechanism of myoclonus with etomidate?
DISINHBITION of extrapyramidal motor activity in the SUBCORTEX: likely cortical activity is suppressed faster than subcortical activity. Patient becomes unconscious from loss of cortical activity but then has myoclonus due to LOSS of cortical inhibition of the SUBCORTEX (until that too is suppressed).