Other Common Drugs Used In Anesthesia Flashcards
What is the mechanism of action of aprepitant?
Neurokinin 1 antagonist (receptors in CTZ- area postrema and nucleus solitarius)
How long does aprepitant last?
48 hours
What is the mechanism of action of milrinone?
Phosphodiesterase iii inhibitor
How do anticholinergics work?
By competitively blocking the binding of Ach
What is the molecular makeup of anticholinergics?
Ester linkage of an aromatic acid with an organic base
What are the CV effects of anticholinergics?
Decreased heart block Atrial arrhythmias Nodal arrhythmias Moderate norepinephrine release (due to blocking presynaptic muscarinic adrenergic receptors) Dilation of cutaneous vessels
What are the respiratory effects of anticholinergics
Decreased secretions
Relaxation of bronchial smooth muscle
What is the effect of anticholinergics of thermoregulation
Inhibits sweat glands so may cause fever
What is the duration of action of aTropine?
30-45 minutes
What is the duration of action of glycopyrrolate
2-4 hours
Which anticholinergic produces more CNS effects?
Scopolamine
Which patients should not be given scopolamine
Closed angle glaucoma
What mechanisms does promethazine act on?
Blocking D2 in CTZ, histaminergic (vestibular afferents) , and cholinergic (muscarinic in nucleus solitarius)
Can cause akathisia and dyskinesia
What is this MOA of alvimopan
Peripherally acting mu opioid antagonist that can decrease opioid associated N/V
What is dronabinol?
Agonist of cannabinoid receptors CB1 and 2
Not effective for PONV!
What is the mechanism of action of metoclopramide?
D2 antagonist
Anti muscarinic
Anti serotonergic
What does metoclopramide due to the GI system?
Increases LES tone
Increases gastric motility
What can hyperbaric oxygen therapy be used for?
Air embolism Decompression sickness Carbon monoxide poisoning Cyanide Carbon tetrachloride Hydrogen sulfide Brown recluse bites Necrotizing infection Chronic osteomyelitis Intracranial abscess Ischemia
What does glycopyrrolate do to the GI system?
Decreases motility
Decreases LES tone
Decreases salivary and gastric secretions
What does glycopyrrolate do to bronchial muscles?
Relaxes bronchial smooth muscle
Why do patients taking SSRIs need more hydrocodone?
Fluoxetine and paroxetine significantly inhibit CYP2D6 and slow conversion of hydrocodone to hydromorphone within the liver
How does mannitol cause pulmonary edema?
By increasing the circulating volume (from increased osmolality) in someone with ventricular dysfunction
How does mannitol decrease ICP.
- Increase extra cellular osmolality so increases volume expansion –» increased cardiac output and therefore CBF which causes a compensatory vasoconstriction of cerebral vessels
- Decreases viscosity of the blood thereby increasing flow in the vessels
Second phase: osmotic gradient and Diuresis across bbb
How long does the mannitol effect on ICP last?
6 hours
How long does it take for mannitol to work on ICP?
30 minutes
What are th side effects of mannitol?
Transient increase in ICP in normal patient Hypotension (fast administration) Pulmonary edema Volume overload Hyperglycemia Renal failure
What is the MOA of gabapentin?
Binds voltage gated calcium channels in CNS which modulates glutamate synthesis, reduced release of monoamine NTs
What is the dosage of sugammadex used for routine reversal neuromuscular blockade?
2 mg/kg
What is the MOA of sugammadex?
It is a cyclodextrin with a lipophilic core and hydrophilic side chains that encapsulate and noncovalently bonds steroidal NMBs
Is sugammadex dosing based of actual body weight or ideal body weight ?
Actual
What is the dose of sugammadex used in people with no twitches?
4 mg/kg
What are the patient populations in which sugammadex is not approved?
Pediatrics
Severe renal failure
Hypersensitivity to cyclodextrin
What medications is sugammadex incompatible with?
Ondansetron
Ranitidine
Verapamil
How is nitric oxide metabolized?
It is inactivated by hemoglobin in the pulmonary vasculature
It is oxidized by hemoglobin to nitrite which in turn binds oxyhemoglobin to make nitrate and methemoglobinemia
Why doesn’t nitric oxide cause hypotension?
Because it is inactivated in the lungs
Which site does gabapentin have most effect on in chronic neuropathic pain?
Calcium channel a2-delta
Which P450 does St. John wort increase?
3A4
What does St. John’s wort increase the metabolism of?
Alfentanil Midazolam Lidocaine Oral contraceptives Antiretrovirals NSAIDS (2C19) Clopidogrel (2C19)
Which antibiotics prolong NMB?
Amino glycosides
Tetracyclines
Polymixin
Lincomycins (clindamycin)
Why do we give clindamycin slowly?
It has been known to cause cardiac arrest if given rapidly
What other classes of drugs can potentiate NMB?
Anticonvulsants (carbamazepine)
Antiarrythmics (verapamil)
Diuretics (furosemide)
What pain drugs that we give shouldn’t be used with methotrexate?
NSAIDs
What does cyclophosphamide do to our NMBs?
Prolongs the action of succinylcholine because it is a pseudocholinesterase inhibitor
How long do the pseudocholinesterase inhibitor effects of cyclophosphamide last after stopping it?
3-4 weeks
Which chemotherapeutic drugs cause neuropathy and autonomic nervous system problems?
Vincristine and cisplatin
What should be avoided in people taking vincristine and cisplatin?
Regional anesthesia since they cause neuropathies
What drugs are contraindicated in the managing malignant hyperthermia?
CCBs due to dantrolene causing more release of Ca from SR with these agents.
What is the initial dose of dantrolene?
2.5 mg/kg
What is the infusion dosing of dantrolene?
0.25 mg/kg/hr
What is the bolus dosing of dantrolene for maintenance?
1 mg/kg every 4-6 hours
Which drug should not be used in ECT and why?
Lidocaine because it decreases seizure duration and you need the seizures to be 25-30 seconds
What is the MOA of tirofiban, eptifibatide, abciximab?
G2b3a receptor inhibitor (prevent platelet aggregation)
How is tirofiban metabolized?
Renally
How long do you have to stop tirofiban and eptifibatide before surgery?
24 hours
How long do you need to stop abciximab before surgery?
72 hours
What happens to hemodynamics after a bolus of dexmedetomidine?
HTN because of peripheral alpha 2 receptors stimulation , then reflex Brady and decreased CO from central alpha 2 stimulation that increases parasympathetic outflow
What is the MOA of cyclopentolate
Anticholinergic
Used to dilate the eyes
Causes systemic anticholinergic symptoms
