GI, CNS Flashcards
antacids
Aluminum Hydroxide - Amphojel
Calcium carbonate - tums - ADR calcium products: hypercalcemia
Calcium carbonate w/ magnesium hydroxide - Rolaids
Magnesium Hydroxide - xind magnesium products: poor renal fxn pts, can lead to diarrhea
Sodium bicarbonate - alka seltzer - can exacerbate HTN/HF - hypernatremia/fluid overload
ADR all - may affect absorption of other medications - alters gastric pH, 1 hr between antacids and other substances
cimetidine
H2 Blockers - 65% decrease in acid secretion
OTC - no longer recommended
liver enzyme inhibitor - many interactions! raises levels of many other drugs phenytoin (szr med), warfarin
crosses BBB - can alter mental status - esp in older adults w/ renal fx
binds to androgen receptors - gynecomastia, reduced libido, and impotence
we now have new, safer H2blockers
famotidine
newer H2 Blocker
Fewer ADRs
Do NOT inhibit liver enzymes
Do not easily cross BBB
No antiandrogenic effects
omeprazole/pantoprazole
PPI - 90% decrease in acid secretion
for ulcer/ulcer pain - should be taken 30 min to 1 hr prior to eating (usually b4 breakfast)
ADRs - long term treatment - pneumonia, osteoporosis(decreases abs Ca), rebound hypersecretion, hypomagnesemia, gastric cancer
Sucralfate
mucosal protectant - forms a gel that coats stomach lining/ulcer - PUD
not helpful in treatment of GERD
nonabsorbable, does not affect acid secretion
misoprostol
analog of prostaglandin (stimulate secretion of mucus and bicarb, promotes vasodilation)
especially approved - prevention of NSAID related ulcer
caution in pregnancy - can cause miscarriage
H. pylori treatment
antibiotics treatment of choice - need more than 1 (2-3) (clarithromycin, amoxicillin, metronidazole, bismuth, tetracycline)
plus an antisecretory agent PPI/H2blkr
associated with gastric cancer - trtmt reduces adenocarcinoma
lifestyle modification - PUD
Avoid foods that exacerbate sx (no longer rec bland diet or caffeine elimination)
Alcohol in moderation
Smoking discouraged
Avoid NSAIDs
ondansetron - serotonin 5HT3 receptor antagonist
MOA: Blocks the serotonin receptor in the CTZ, as well as the intestinal wall and stomach - works in CNS and stomach
most effective drug available for suppressing N/V
admin: under the tongue (sublingual disintegrating), IV, PO
EKG -Risk for prolongation of QT Interval - can lead to ventricular dysrhythmias
other adrs: HA, dizziness, drowsiness, diarrhea - most common with repeated dose
haloperidol
antiemetic - dopamine antagonist- butyrophenone
FGA
ADRs: Extrapyramidal (EPS), Sedation, Hypotension, NMS
Associated with Fatal Dysrhythmia-prolong QT √ ECG - pre and during dosing
droperidol
antiemetic - dopamine antagonist - butyrophenone
stronger sedative than haloperidol
ADR - respiratory depression - BBW - intubation,
metoclopromide
Antiemetic - dopamine antagonist
MOA: blocks dopamine receptor & prokinetic - gastric emptying
ADR: sedation and diarrhea, ask GI hx xindic - GI beed, obstruction, perforation
may cause EPS
promethazine (phenergan)
Antiemetic - type - dopamine antagonist - Phenothiazines -
xind - peds + elderly - respiratory depression
ADR: sedation (leading to srs resp depression)
IV - vessicant - tissue necrosis from infiltration
Cannabinoid - dronabinol
Nabilone
MOA: Activates cannabinoid receptor in CTA
USE: CINV
Also appetite stimulate: CA, HIV/AIDS or adjunctive pain med
Active ingredient found in marijuana
ADR: Can produce the same subjective effects identical to those caused by smoking marijuana
Drowsiness, dizziness, impaired cognition, euphoria…
avoid alcohol other CNS depressants
pts that use a lot of MJ can require more opioids
Aprepitant
Neurokinin antagonist - blocks neurokinin-type receptors in the CTZ
delayed effectiveness - added to ondansetron for additional
ADR - fatigue
lorazepam
benzodiazepine
MOA: Enhance GABA Three benefits of Benzodiazepines in the treatment of N/V:
-Sedation
-Suppression of anticipatory nausea/vomiting
-Produces anterograde amnesia
-loss of ability to create “new” memories
Use: Frequently in combination with other antiemetics for CINV
methylprednisolone/dexamethasone
used off label for CINV
combo treatment - dexamethasone + substance P/N1 antagonist (aprepitant) or 5HT antagonist
dronabinol
MOA: Activates cannabinoid receptor in CTA
USE: Chemotherapy-induced N/V
Also appetite stimulate: CA, HIV/AIDS or adjunctive pain med
Active ingredient found in marijuana
ADR: Can produce the same subjective effects identical to those caused by smoking marijuana
Drowsiness, dizziness, impaired cognition, euphoria…
Should avoid alcohol and other CNS depressants
Schedule III drug
dymenhydrinate/diphenhydramine
antihistamines
anticholinergic s/e, sedation, xind: glaucoma
30min-1hr before activity
scopolamine
best for motion sickness
behind ear - 4 hr b4 activity
anticholinergic side effects - xind: glaucoma
Diphenoxylate with Atropine
opioid - only indic. is diarrhea
schedule V - controlled (added atropine - anticholinergic (dry mouth, urinary retention) - deterrent for abuse)
Loperamide
Analog of meperidine (synthetic opioid)
No narcotic or analgesic effect - does not cross BBB
Not regulated under the controlled substance act
(immodium)
ciprofloxacin
traveler’s diarrhea - most common cause - E coli, loperamide may also be used (may prolong infection/delay progression)
bismuth subsalicylate
pepto bismol
ADR: may cause black stools,
excessive use - ringing in the ears (contains derivative of aspirin - if taken with aspirin could start having sx of aspirin toxicity - ringing in ears)
Polycarbophil/methycellulose/psyllium
bulk forming laxatives
Natural fibrous substance - promote large, soft stools
MOA same as dietary fiber - indigestible/nonabsorbable
first line treatment - reduces risk of colon cancer
ADRs: can solidify in the GI –> obstructions with insuff fluid intake
xindic- people who cannot drink lots of fluid (HF)
Docusate Sodium/Calcium
Surfactant Laxative -
MOA - inc intestinal fluid secretion & inhibits fluid absorption - retain fluid in stool
considered “lubricants” and “stool softeners”
often rx’ed with opioids
prophylaxis - p/s MI, surgery, vaginal delivery
beneficial for elderly who cannot drink adequate fluids for bulk laxatives
Bisacodyl/senna/ castor oil
Stimulant Laxative
MOA: irritating sensory nerve endings in the mucosa to stimulate motility and fluid movement
xind: diarhea
should be rx’ed PRN
onset of action 6-8 hrs - crampy and water discharge
ADRs: Associated with fluid loss and can lead to dependency
Frequently used and abused - Especially Dulcolax and Ex Lax
Magnesium hydroxide
sodium phosphate
saline laxatives - osmototic laxatives - poorly absorbed salts -osmotic draw water into int
milk of mag
ADRs: can cause significant loss of water, pt should inc fluid intake. small amounts of mg or na will be absorbed - if mg - monitor renal function, xindic kidney disease mg accumulates, if na - na can cause fluid retention xindic pts with HF/HTN
pt should be encourange to drink adequate water, kidney fxn should be checked
lactulose
saline osmotic laxative
poorly absorbed - draws water into intestine to form soft stool
enhances secretion of/decreases serum ammonia levels and may be prescribed for this purpose (hepatic encephalopathy)
ADRs: flatulance, cramping
Polyethylene Glycol
Osmotic Laxative
indicated for chronic constipation
ADR: nausea, bloating, cramping, flatulance
eg. miralax
bowel cleansing/prep - this drug + electrolyte solution - isosmotic/nonabsorbable - ok for renal impairment/HF
alosetron
treatment for IBS
selective blockade - 5-HT receptors on neurons that innervate viscera
MOA- change in transit time, inc absorption of fluid/Na, increased firmness of stool
ADR: constipation, impaction, obstruction, ischemic colitis (d/c med)
orlistat
MOA - inhibition of gastric/pacreatic lipases - decreases absorption of fats
approved >12yo
ADR: oily seepage, flatulance w/ leakage, fecal urgency, dec vitamin absorption
dose w/ bulk laxatives to reduce GI effects
classes of parkinsons drugs
Dopaminergic
Converts to Dopamine- medications undergoes conversion to DA
Dopamine Agonists
Mimics the action of Dopamine on the Dopamine Receptors
COMT Inhibitors
Inhibits an enzyme that inactivates Dopamine.
MAO-B Inhibitors
Inhibit MAO-B enzymes that interfere with Dopamine. Prolongs the action of Dopamine.
Anticholinergics
Blocks Cholinergic Receptors
carbidopa/levadopa
also approved for restless leg syndrome
dopamine cannot cross BBB - levodopa converted to dopamine after crossing BBB
c is added to l (no pharm benefit by itself) - enhances l delivery to brain, slows metabolization in intestine(w/o-2%, w/- 10%) - allows lower dosing
ADRs: n/v by most pts, dyskinesia, postural hypotension, dysrhythmias (dopamine conversion in periphery leads to excess activation of beta 1), psychosis (20% of pts) - psychosis
dark sweat/urine, can activate malignant melanoma, on-off phenomenon
high protein meals can reduce therapeutic responses (reduces absorption) - may be cause of “off”
d-d
+ FGA - decreases effectiveness
+ MAOI - hypertensive crisis - elevated dopamine + norepi - a1, b1&b2
pramipexole/ropinirole
dopamine agonists
stimulates dopamine receptors directly
drug of choice - mild symptoms, added to Levodopa/Carbidopa for elderly/advanced
also approved for restless legs
advantages - don’t lead to dyskinesias, not dependent on enzymatic activation, don’t compete with proteins for absorption and transport across BBB, lower incidence of response failure
ADRs: hallucinations, daytime sleepiness, postural hypotension
entacapone
COMT inhibitors - enzyme inactivates dopamine
supports levodopo - not monotherapy
also decreases metabolism of levodopa in periphery (thereby inc t1/2) - allows lower dosing, decreases wearing off of levodopa
ADRs: primarily from inc levodopa levels - may need to decrease dose, do not stop abruptly
on its own - GI - diarrhea, constipation, n/v, discoloration of urine
selegiline
MAO-B inhibitors - enzyme that breaks down several chemicals in brain - inc dopamine
leaves more available dopamine, modest improvement in motor sx
avoid tyramine, sympathomimetics- hypertensive crisis - in large doses MAO-A will be inhibited as well
+ SSRI - serotonin sydnrome
can be used alone or w/ levodopa
first line drug - may delay neurodegeneration - use early
amantidine
first available as antiviral, found to effective parkinsons
unclear MOA
not considered first line - may have + treating levodopa dyskinesias
benzotropine
anticholinergic parkinson’s - blocks receptors in striatum
reduces tremors/rigidity - does not decrease bradykinesia
not as effective as levodopa or dopamine agonist, may be used early, for younger pts, avoided in older pts - intolerant of CNS side effects (sedation, confusion, delusions, hallucinations)
ADRs: anticholinergic
Donepezil hydrochloride
Acetylcholinesterase inhibitor
best tolerated
all stages of AD
ADRs:GI: N/V , diarrhea, dyspepsia- Take with food
Dizziness, HA,
Respiratory: Bronchoconstriction
**CV: bradycardia **
Low cardiac output= fainting , falls , injuries
avoid anticholinergics/ anticholinergic s/e - atropine, antihistamine, TCA, FGA
Rivastigmine
Galantamine
Acetylcholinesterase inhibitor
mild to moderate AD
ADRs:
(same as donepezil)
GI: N/V , diarrhea, dyspepsia- Take with food
CNS: Dizziness, HA,
Respiratory: Bronchoconstriction
CV: bradycardia
Low cardiac output= fainting , falls , injuries
Memantine
NMDA receptor antagonist
NMDA receptor + glutamate -> allows calcium into cell - MOA- slows influx of calcium
indic for moderate to severe disease (only drug rec’ed for severe dx)
ADRs: dizziness, HA, confusion, constipation, hallucination
Aducanumab
monoclonal antibody - removing amyloid plaques
expensive
40% of pts ADRs - cerebral swelling, brain bleeding, HA, falls
classes of AE agents
Suppression of sodium influx -Phenytoin, Carbamazepine
Suppression of calcium influx- Ethosuximide , Valproic Acid
Promotion of Potassium Efflux- Potassium leaves the cell- Ezogabine
Block receptors for Glutamate - primary excitatory neurotransmitter- Topiramate
Potentiate action of Gamma-aminobutyric Acid (GABA) -primary inhibitory neurotransmitter
Benzodiazepines, Gabapentin
**Narrow therapeutic range
Take as directed and on time, each day
Non-adherence accounts for @ 50% of treatment failure
must be withdrawn slowly 6wks - months (abrupt w/d - rebound seizures, status epilepticus
Phenytoin
traditional AED
selective inhibition of sodium channels - selects for hyperactive neurons
all forms of seizures except absence
may be used as antidysrhythmic
narrow therapeutic range - 10-20 mcg/mL - s/s toxicity - nystagmus, cognitive impairment, ataxia, diplopia, sedation, cardiac depression -
no antidote
active against partial seizures/tonic-clonic
ADR: gingival hyperplasia -20% (soft toothbrush, continue to floss), derm - rash that can progress to SJS or TENs, IV - tissue vessicant, hypotension/dysrythmias,hirsutism, **teratogen + inc bleeding for newborns,
Fosphenytoin
prodrug - converted to phenytoin
admin IM/IV only
parenteral mgmt of status epilepticus, treatment/prevention of seizures - neurosurgery
ADRs: same as phenytoin + infusion reaction - itching
cardiac monitoring
Carbamazepine
trad AED
suppression of sodium influx, potentiates GABA
active against partial seizures/tonic clonic
+ bipolar, trigeminal neuralgia, diabetic neuropathy
narrow therapeutic range - nystagmus, ataxia, sedation - less cognitive impairment vs phenytoin and pentobarbital- drug of choice
Tolerance can develop- minimize by giving largest dose at bedtime
ADR: monitor CBC - bone marrow suppression- thromcytopenia, leukopenia, anemia
fetal harm, SJ, CNS - nystagmus, ataxia, sedation (less than phenytoin)
hyponatremia/osm - promotes secretion of ADH -> fluid retention - monitor Na (looks like SIADH)
liver enzyme inducer - decreases effect warfarin, OCP, x grapefruit juice - inc peak and trough
Valproic acid
trad AED
MOA: Suppression of Na influx, Ca influx & Augments GABA
V is for variety - broad spectrum effectiveness - partial/focal seizures, generalized tonic-clonic
monitor for hepatoxicity, pancreatitis
other ADRs: teratogen, hyperamonemia - monitor neuro, GI most common - min w/ enteric coating/taking with food
Ethosuximide
Absence seizures, also works in some partial seizures
initial dose drowsiness, dizziness, lethargy wears off over time
Phenobarbital
older AED - potentiates and mimics effects of GABA
still used, rarely due to adrs
used in low doses for alc w/d
generalized & partial seizures
ADRs: CNS depression, learning impairment, depression
misuse
Levetiracetam (Keppra)
MOA: unknown, binds GABA
widely used in acute care for all ages - not effective absence
offlable for migraines, bipolar, new-onset pediatric epilepsy
least risk of ADRs and least risk of abuse/dependence
newer - used a lot
ADR: mild CNS - drowsiness, weakness, mood chgs, agitation
safe in pregnancy
Lamotrigine (Lamictal)
newer AED
MOA: Blocks Sodium and partially Calcium Channels, and decreases Glutamate
generalized, partial and absence szr
ADR: CNS, derm
monitor for SI
does not induce or inhibit liver enzymes/drug metabolism
Pregabalin (Lyrica)
analog of GABA - similar to gabapentin
unknown MOA- inhibits Ca influx
seizures, neuropathic pain - DM neuropathy, fibromyalgia, neuralgia
ADR: CNS -dizziness, sedation, brief blurred vision
abuse - 4-12% euphoria, similar effect benzos
d/c slowly- avoid insomnia, HA, s/s dependence,
Gabapentin (Neurotin)
partial seizures + broad spectrum antiszr
analog of GABA
80% rx’ed offlable - neuropathic pain, neuralgia, migraine prophylaxis, fibromyalgia, meno hot flashes
ADR - mild CNS, peripheral edema -disapear with continued use
Oxcarbazepine(Trileptal)
Generalized and partial seizures
monotherapy or adjunct
derivative of carbamazepine - shared features, better tolerated, more expensive
ADR: monitor CBC - bone marrow suppression- thromcytopenia, leukopenia, anemia
fetal harm, SJ, CNS - nystagmus, ataxia, sedation (avoid alcohol)
hyponatremia/osm - promotes secretion of ADH -> fluid retention - monitor Na (looks like SIADH
liver enzyme inducer - decreases effect warfarin, OCP, x grapefruit juice - inc peak and trough, increases phenytoin levels
status epilepticus treatment
Immediate IV placement for labs and treatments
Glucose solution infused
Antiepileptic agent infused
Benzodiazepines: Lorazepam (Ativan) or Diazepam (Valium) to terminate seizures - GABA agonists
Effects of Ativan can last for 72 hours, so it is now the drug of choice
Once the seizures have been stopped, Phenytoin (Dilantin) or Fosphenytoin (Cerebyx) may be given for long term suppression
migraine physiological
dilation/inflammation intracranial blood vessels - trigeminal depolarization, increase in CGRP, decrease in serotonin
mds prevent or abort
sumatriptan
first line treatment - abortive therapy
moa: stimulate 5-ht receptors in cranial blood vessels - vasoconstriction
15 min - subQ/intranasal. 30-60 min intranasal
ADR: 50% heavy arms, chest pressure
avoid in pregnancy, xind: angina, CAD - coronary vasospasm, uncontrolled HTN
seperate from ergotamine compound 24 hrs
+ SSRIs, SNRIs, MAOIs - SS
opioids - butorphanol
INH agent
severe migraines
t1/2 shorter than migraines - abuse, medication overuse headache
ergotamine
promotes vasoconstriction
second line therapy r/t risk of dependency
often + caffeine
not safe during pregnant - cat x
overdose - extreme vasoconstriction - “ergotism” - severe tissue ischemia in the periphery
xind: angina, CAD - coronary vasospasm, uncontrolled HTN
ADR: n/v (often + metoclopramide or procholperazine), leg weakness, myalgia, peripheral tingling, tachy, brady, angina
d-d: 24 hours from triptans
rebound headaches may occur - limit use 5/week or 10/week combo drug
ubrogepant
Calcitonin Gene Related Protein - CGRP antagonist
CYP inhibitor - may delay absorption of high fat meal
botox
> 15 attacks/month
31 injections
helpful in some cases
cluster headaches
oxygen, CCBs
seizures
AEDs - suppress discharge of neurons within a seizure focus AND suppress propagation of seizure activity from the focus to other areas of the brain - 60-70% are seizure free
goals for treatment - reduce seizures - normal life / eliminate seizures
monitor plasma levels - phenytoin (dilantin),
nonadherence - 50% of treatment failures
seizure meds should not be stopped abruptly
take meds at same time every day
ADR: CNS depression
all AEDs can cause Steven’s Johnsons - first flu-like, then rash
migraines
prevent/avoid attacks:
bblkrs - stablize vascular tone
TCAs - amitriptylline - blocks reuptake norepi, serotonin ADR: hypotension, anticholinergic
AED - topiramate, divalproex (form of valproic acid)- strongest efficacy, gabapentin
abortive therapy:
nonspecific - ASA, acetaminophen, opioids
specific- serotonin agonists - triptans, ergot alkaloids
aspirin + metoclopromide can be as effective as sumatriptan w/ less adrs (gastric stasis common with migraine meds - good reason to add metoclopramide
