Preop Medication/Antiemetics 2-3 Flashcards
Test 1
Histamine is endogenous. What does this mean?
It is in our body all the time
What is histamine released from?
Basophils
Mast cells
What does histamine induce?
smooth muscle contraction in airways
-secretion of acid in stomach
-release of neurotransmitters in CNS (Acetylcholine, NE, Serotonin)
What are we worried about with endogenous histamine release?
Bronchospasms
-painful aspiration
Which drugs induce histamine release?
Morphine
Mivacurium (Mivacron)
Atracurium (Tracrium)
Protamine
How do we treat drug induced histamine released?
Both H1 & H2 antagonist
Have to give both
What receptors does histamine receptors H1 & H2 activate?
H1: Muscarinic, cholinergic, 5-HT3, Alpha-adrengic
H2: 5-HT3, B-1
What drug do we give in the OR almost everytime we give heparin?
Protamine
Which generation of drugs typically block the histamine cascade reaction?
1st generation antihistamine drugs such as benadryl
What are the presentations that you’ll see from histamine release from the H1 & H2 receptors?
H1: Hyperalgesia; inflammatory pain
H2: Increases cAMP (B1 stimulation –> inreases HR); increases acid/volume production
Both: Hypotension, capillary permeability, flushing, prostacyclin release
How does histamine release cause hypotension?
H1&H2 activation causes hypotension from release of nitric oxide & capillary permeability
Histamine receptor antagonist are actually _______ agonists
inverse
T/F: Histamine receptor antagonist prevent the release of histamine
F
Responds to the release of histamine
Where are H1 receptors located?
Vestibular system
airway smooth muscle
cardiac endothelial cells
What types of patients should we be cautious with H1 receptor antagonist? Why?
Ambulatory
elderly
Crosses BBB & makes you sleepy –> can fall more easily
Beside histamine induced reactions, what is another H1 receptor antagonist indication?
Motion sickness
H1 receptor antagonist should provide protections against _______ & ________ stability
brochospams
cardiac
H1-R antagonists has _______ tachyphylaxis? What does this mean?
little
should not decline in effectiveness with doses.
What are SE of H1-R antagonists?
Blurred vision
Urinary retention
Dry mouth
Drowsiness (1st gen)
BUDD
What are 2 1st gen H1-R antagonists?
- Diphenhydramine (benadryl)
- Promethazine (phenergen)
What are 2 2nd gen H1-R antagonist?
- Cetirizine (Zyrtec)
- Loratadine (Claratin)
What are general benefits of H1-R antagonists?
Cheap & effective
Benedryl is a ____ receptor ______
H1
antagonist
What is diphenhydramine (benadryl) mostly used for?
-antipruritic (itching)
-pre-treat procedure related allergies (ex. contrast)
-anaphylaxis/allergic reaction
What is the half time for Diphenhydramine (Benadryl)?
7 - 12 hours
Diphenhydramine (Benadryl) may inhibit the ________ arc of oculo-_________ reflex. What does this mean?
afferent
emetic
If push on eyeball –> will not vomit
Diphenhydramine (Benadryl) ___________ ventilation
Stimulates
What is the dose for Diphenhydramine (Benadryl)?
25 - 50 mg IV
can give 1/2 the dose if worried
What is promethazine (phenergan) mostly used for?
Anti-emetic
(even better than Zofran)
What is the half time for promethazine (Phenergan)?
9 - 16 hours
What are the black box warnings for Promethazine (Phenergan)?
-fatal, respiratory arrest/micro spasm in < 2 yo
-if infiltrates in IV –> ischemia and loss of limb
What are 2 considerations that we should have with Promethazine (Phenergan)
- Do not give in children <2yo
- Make sure the IV works very well or use picc/cvc
What is the dose for Promethazine (Phenergan)?
12.5 -25 mg IV
Can also give IM, PO
What is the onset for Promethazine (Phenergan)?
5 minutes (IV)
Promethazine (Phenergan) works well as a “rescue”. What does this mean?
Works well even if they are already vomiting. Can give if Zofran failed.
Promethazine (Phenergan) also reduces __________ pain levels and have __________ affects
Peripheral
Anti-inflammatory
What does H2-R antagonist Tx? How does it do this?
Duodenal Ulcer disease
GERD
By decreasing hyper secretions of gastric fluids –> decreases gastric volume
-increases stomach pH
What SE does H2-R antagonists have?
Diarrhea
-HA
-skeletal muscle pain
-confusion
-bradycardia
-increase serum creatinine 15%
**weakened gastric mucosa dt bacteria (prolonged administration) –> increase pulmonary infections & overgrowth of Candida albicans
What symptom does H2-R antagonist cause with prolonged administration? Why?
Increased pulmonary infections
-of a growth of candida albicans
Increasing the pH in the stomach, weakened the gastric mucosa, allowing increased amounts of bacteria.
H2-R antagonists are metabolized in the _______ and cleared in the _______
Liver
Kidney
Cimetidine (Tagamet) strongly inhibits _________. Which includes which drugs? How does this affect them?
CYP450
Warfarin
-Phenytoin
-lidocaine
-tricyclics
-propanolol
-nifedipine
-meperidine
-diazepam
These drugs are not going to be metabolized as quickly and will build up in your system to possible toxic levels.
What are AE of Cimetidine (Tagamet)?
Bradycardia & Hypotension (cardiac H2-R during rapid infusions)
-increased plasma levels of prolactin (increases milk, production)
-inhibits dihydrotestosterone binding to androgen receptors (causes impotence –> ED)
What is the dose for Cimetidine (Tagamet)?
150 -300 mg IV
Renal impaired: 75 - 150 mg IV
half of normal dose
What is the only difference between Ranitidine (Zantac) & Cimetidine (Tagamet)?
Ranitidine (Zantac) binds weaker to CYP450 enzymes. So if Im on a drug that is metabolized by CYP450, I would choose Ranitidine (Zantac) bc metabolism of those types of drugs wouldnt be as impaired.
What is the dose for Ranitidine (Zantac)?
50 mg diluted to 20 cc
Renal impaired: 25 mg (1/2 normal)
give over 2 minutes
Which H2-R antagonist has no CYP450 interference?
Famotidine (Pepcid)
Famotidine (Pepcid) is the most ______ H2-R antagonist
potent
What is the halftime for Famotidine (Pepcid)?
2.5 - 4 hrs
Famotidine (Pepcid) interferes with _________ absorption and causes _______. What type of patient should we not give this in?
Phosphate
Hypophosphatemia
A patient that has Ca/Phos bone issues
what is the dose for Famotidine (Pepcid)?
20 mg IV
Renal: 10mg (1/2 normal)
How do PPIs work?
Irreversibly bind to acids secretion pumps (only inhibit the pumps that are currently working, we are constantly making new pumps)
-inhibit the movement of protons across the gastric parietal cells
What is the onset for PPIs?
Up to 5 days
PPIs are most effective for?
Control a gastric pH
-decrease gastric volume
What disease process are PPIs more effective for treating than H2-R antagonist?
Esophagitis
-ulcers
-GERD
-Zollinger-Ellison syndrome
What is the best Tx for Zollinger-Ellison syndrome?
PPI
What are side effects of long-term PPI use?
-bone fx
-SLE (lupus)
-acute interstitial nephritis
-Cdiff
-Vit B12/Mag deficiency
PPIs blocked the enzyme that activates ___________
Clopidogrel
PPIs inhibit the metabolism of __________ (list). What effect does this have?
Warfarin
-antibiotics
-antifungals
-anti-seizure
These medications will stay in your system longer
INR will be increased
Why do PPIs only work when you continue to take them?
Acid inhibition increases with repeated doses bc they inhibit new pumps that are being made. PPIs only inhibit the pumps that are currently there.
Omerprazole (Prilosec) is a ______ and is a _______
PPI
Prodrug
What is the dose for Omerprazole (Prilosec)?
40 mg in 100cc NS
give over 30 minutes
or PO > 3hrs prior (last oral intake more than 3 hours ago)
What are SE of Omerprazole (Prilosec)?
-HA
-agitation
-confusion
-abdominal pain
-N/V
-flatulence
-small bowel bacteria overgrowth
What are the 3 signs that something crosses the BBB?
-HA
-agitation
-confusion
How does Pantroprazole (Protonix) compare to Prilosec (Omerprazole)?
-greater bioavailability (less lost in 1st pass effect)
-longer halftime
When can we give Pantroprazole (Protonix)? What effect does it have?
1 hour prior
Decrease gastric volume and pH
What drugs are PPIs?
Omeprazole (Prilosec)
Pantoprazole (Protonix)
Lansoprazole (Prevacid)
Dexlansoprazole (Dexilent)
What is the dose for Pantroprazole (Protonix)?
40 mg in 100cc
give over 2-15 minutes
What is our DOC for aspiration pneumonitis & intermittent heart burn? Why?
H2-R antagonists
They dont take long to work. PPIs take a bit longer to work
What are the 2 types of antacids? What are their bases? Which one do we use an anesthesia? How does it work?
- Particulate: Aluminum/Magnesium based
- Non-particulate: sodium, carbonate, citrate, bicarbonate based –> neutralize acid
non-particulate is used in anesthesia
Why are antacids not a good choice for longterm use?
-Increase pH: inhibit breakdown of food & increase bacteria
- magnesium based: osmotic diarrhea & hypermagnesium –> neuro/neuromuscular impairment
-Calcium based: hypercalcemia –> kidney stones
-sodium based: hypernatremia –> HTN/CHF
What is Sodium Citrate? How does it work? What do we use it for?
Nonparticulate antacid
It is an alkaline (base) & works by combining with stomach acid to neutralize (creates salt, co2, water)
Uses: prevents aspiration pneumona (NOT ASPIRATION!! CAN ASPIRATE)
Sodium Citrate ________ intragastric volume
increases
How fast does Sodium Citrate work? how long does it last?
immediately
loses effectiveness 30-60 minutes
What is the dose for Sodium Citrate?
15 - 30cc PO
How do dopamine blocker work?
Stimulate gastric motility (prokinetic)
-Increases lower esophageal sphincter tone
-relaxes pylorus/duodenum
-stimulates peristalsis
has everything move down
What kinda of pts do we not want to give dopamine blockers to? why?
parkinsons
huntingsons
depletes dopamine even further
What are SE that dopamine blockers have?
Crosses BBB –> extrapyramidal reactions
-orthostatic hypotension`
What drugs are dopamine blockers?
Droperidol (inapsine)
Domperidone
metoclopramide (reglan)
Dopamine blockers have effects on ___________ trigger zone. What does this mean?
Chemoreceptor
great for chemo induced N/V
What is the drug for Diabetic gastroparesis?
Metoclopramide (reglan)
What is your dose for Metoclopramide (reglan)?
10 - 20 mg IV
give over 3-5 minutes (15-30 mins prior to induction)
What are the SE of Metoclopramide (reglan)?
-abdominal cramping (if rapid IV)
-muscle spasms
-hypotension
-sedation (crosses BBB)
-increases prolactin release
-neuroleptic malignant syndrome
-decreases plasma cholinesterase levels –> slow metabolism of succs, mivacurium, ester local anesthetics
neuroleptic malignant syndrome mimics what? What are the S/S?
MH
-increase temperature
-muscle rigidity
-tachycardia
-confusion
What are some facts about domperidone?
Does not cross BBB
-No anticholinergic activity
-increases prolactin levels (greater degree)
-not approved in US: causes dysrhythmia and said death
Droperidol (Inapsine) is related to ______ and was developed for what type of diseases?
Haldol
Schizophrenia and psychosis
Droperidol (Inapsine) has what type of SE?
Extrapyramidal symptoms
-neuroleptic malignant syndrome
What type of drugs do you want to avoid with Droperidol (Inapsine)?
Other CNS depressants: barbiturates
-opioids
-General anesthetic
Droperidol (Inapsine) is more effective than _________ & equally effective as __________
Metoclopramide
Zofran (4mg)
What are the black box warnings for Droperidol (Inapsine)?
-prolonged QT intervals/torsades with higher doses
-serious drug interactions: amiodarone
-diuretics
-Sotalol
-mineralocorticoids
-CCB
Where is serotonin released from?
Chromaffin cells in small intestines
Serotonin stimulates _____ afferents through ______ receptors. What does this cause?
Vagal
5HT3
Vomitting
Where are 5HT3-R?
Ubiquitous!!!
Kidney, colon, liver, lungs, stomach
High concentration: brain & GI tract
CINV =
Chemo induced N/V
5HT3 antagonist were originally used in what?
CINV
T/F: 5HT3 antagonist are good for motion sickness/vestibular stimulation
F
What are the side effects for 5HT3 antagonist?
Virtually none
What drugs are 5HT3 antagonist?
-Ondansetron (Zofran)
-Granisetron (Kytril)
-Dolasetron (anzemet)
What are SE of Ondansetron (Zofran)?
HA
Diarrhea
slight prolong QT
What drugs are Ondansetron (Zofran) equivalent to?
Droperidol
Dexmethasone
metoclopramide
What is the half time of Ondansetron (Zofran)?
4 hours
When should we give Ondansetron (Zofran)?
Right before emergence
What is the dose of Ondansetron (Zofran)? What dose literature say about dosing?
4 - 8 mg IV
literature states that 4mg is the ideal dose
Corticosteroids are used in ________
PONV
CINV
How do corticosteroids work as an antiemetic?
MOA unknown exactly:
-thought to inhibit prostaglandin synthesis & endorphin release
-antiflammatory –> less preop pain –> less opioids –> less N/V from opioids
What drugs are corticosteroids?
Dexamethasone (Decadron)
What is the onset of Dexamethasone (Decadron)? How long does it last?
2 hrs
24 hrs
When do we want to give Dexamethasone (Decadron)?
Usually 2/3 hrs before emergence
if difficult intubating or trauma during Sx –> give medication
What are the SE of Dexamethasone (Decadron)?
Diabetic risk of preoperative hyperglycemia (minimal w/ 1 dose)
-perineal burning/itch
What is the dose for Dexamethasone (Decadron)?
4-8mg or more if trauma
Scopolamine patches are ________. What are they used for?
Muscarinic antagonist of ACH
antiemetic/motion sickness
What is the peak concentration for Scopolamine? When do we apply it?
8 - 24 hrs
4 hrs preop (will start working during Sx)
What SE does Scopolamine cause?
dilated pupils
dries up spit (antisialagogue)
causes sedation
What is the dosing for Scopolamine? How long does it work?
Priming dose: 140 mcg –> 1.5 mg over next 72 hours
Lasts for up to 3 days
Bronchodilators are __________ and are structurally similar to ________
Beta-R agonists
epinephrine
How does Bronchodilators work?
GS –> increase cAMP –> decrease Ca++ entry –> decrease contractile –> relaxes smooth muscle
You take ____ puffs of a Bronchodilator every ____ minutes and it increases your FEV by _____
2
6
15%
Can you give Bronchodilators for severe asthma attacks in preop?
Yes, but dont expect to have Sx immediately after. Need to wait and observe. If it doesnt get better –> reeval or maybe even reschedule Sx
MDI =
metered dose inhaler
How do you take a MDI?
2 puffs
While taking slow/deep breath over 5-6 secs
Hold breath at max inspiration for 5-6 secs
You can give Bronchodilators with a MDI or _______ via ETT or a flowmeter
nebulized
What are SE of Bronchodilators?
Tremor
-tachycardia
-hyperglycemia
-transient decrease in arterial oxygenation
Why does a transient decrease in arterial oxygenation happen in Bronchodilators?
Alveoli has more surface area from Bronchodilator –> for a brief moment, carrying away less O2 bc opened alveoli that weren’t previously being ventilated –> as soon as CO2 out and O2 in arterial O2 improves dramatically
What drugs are Bronchodilators?
Albuterol (Proventil)
-Levo-albuterol (xopenex)
What’s the difference between albuterol and Xopenex?
xopenex has less SE, but works a little bit less than albuterol.
Albuterol works better, but has more SE
T/F: You can use a syringe to give albuterol via a face mask
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