Pharmacology Flashcards
Natural opioids include?
morphine and codeine
What is the MOA of opioids?
Binding to mu, kappa, delta receptors lowers presynaptic Ca2++ influx and increases postsynaptic K+ transport; which together reduce synaptic action potential transmission of central pain fibers
What are the different roles of the receptors that opioids act on?
Mu1
Mu2
Kappa
Delta
Mu1 = pain reduction (#1 opioid receptor)
Mu2 = respiratory depression, nausea/vomiting
kappa = respiratory depression
delta = pain reduction
What are notable side effects of opioid medications?
- Respiratory depression/death
- hypogonadism/low testosterone (low motivation, diminished personality)
Special indication for codeine in stroke patients?
Aborting intractable tension headaches, especially in neurologic disease (stroke)
Which opioid is also an NMDA antagonist?
Methadone
Which opioid has mixed agonist-antagonist activity?
Buprenorphine
Which opioid is a mu agonist and seratonin-norepinephrine reuptake inhibitor with increased risk of seratonin syndrome?
Tramadol
MOA of acetaminophen?
inhibiting prostaglandin production (COX enzyme) in CNS - inhibits pain and fevers centrally
Why are NSAIDs sometimes contraindicated following procedures/surgery?
To allow for proper healing and pro-inflammatory response
which NSAIDs are COX-2 selective?
Celecoxib, meloxicam
What is the MOA for the analgesic properties of amitriptyline?
modulation of descending inhibitory pathways that arise in the brain stem centers and synapse within the dorsal horn of the spinal cord
Neurons in these tracts are primarily seratonergic and noradrenergic
*can contribute to seratonin syndrome
Side effects of amitriptyline?
QT prolongation
Anticholinergic side effects (dry mouth, urinary retention, constipation)
MOA of Gabapentin/Pregabalin?
Blocks L-type Ca2++ channels in the CNS (inhibits synaptic transmission)
Which indications is pregabalin FDA approved?
diabetic neuropathic pain
postherpetic neuralgia
fibromyalgia
MOA of duloxetine?
SNRI
*can contribute to seratonin syndrome
MOA of carbamazepine?
Inhibits Na+ channels on neurons, preventing signal transmission along nerves
*trigeminal neuralgia
MOA of capsaisin?
depletes substance P
MOA of corticosteroids?
Inhibits PLA2 enzyme (thus inhibiting arachidonic acid production and prostaglandin production)
Which steroids are particulate?
Which steroid is nonparticulate?
particulate: triamcinolone, methylprednisolone
non-particulate: dexamethasone
MOA of baclofen?
Centrally acting Gaba(B) agonist
- GABAb1 binding inhibits presynaptic Ca2++ into neuron
-GABAb2 binding increases postsynaptic K+ conductance
Side effects of baclofen?
sedation
constipation
lowers seizure threshold
signs of baclofen withdrawal?
ITB - Itchy, twitchy, bitchy
Clearance of baclofen?
Renally cleared
MOA of diazepam (spasticity)?
centrally acting GABAa agonist
- GABAa binding increases presynaptic Cl- influx into neuron
Clearance of diazepam?
Hepatically cleared
MOA of tizanidine?
centrally acting alpha-2 agonist (as is clonidine) –> inhibits spinal reflex arc
Signs of tizanidine withdrawal?
HTN, tachycardia, anxiety, worsened spasticity
Clearance of tizanidine?
Hepatically cleared - check LFTs prior to starting and monitor once starting
MOA of Dantrolene?
peripherally acting - binds ryanodine receptors on sarcoplasmic reticulum, inhibits influx of Ca2++ from SR into cell
Clearance of dantrolene?
hepatically cleared, check LFTs prior to starting, monitor while starting med
MOA of botulinum toxin?
Inhibit presynaptic syntaxin, synaptobrevin, and SNAP-25 proteins which store ACh prior to being released into synapse
Black box warning for botulinum toxin?
distant toxin spread may cause dysphagia, respiratory depression
Docusate MOA
“grease the groove” - stool softener that allows water and fat into stool
MOA of senna?
stimulant that irritates the bowel wall to promote peristalsis
MOA of polyethylene glycol (miralax)?
osmotic laxative that pulls fluid into bowel lumen, promoting urgency of BM
Lactulose MOA?
traps NH3 in bowel, allowing it to be excreted, also a powerful osmotic laxative
*consider KUB to r/o bowel obstruction before starting
Bisacodyl MOA?
rectal wall irritant that is used to stimulate rectal propulsion and evacuation of stool
Lubiprostone (Amitiza) MOA for chronic constipation?
increases intestinal fluid secretion and promotes GI motility through activation of type 2 Cl- channels
Methylnaltrexone (relistor) MOA?
Blocks Mu receptors outside CNS to improve GI motility
Indicated for opioid-related constipation
Oxybutynin/Tolterodine MOA?
strong anticholinergic medication that inhibits cholinergic activity upon muscarinic detrusor muscle to spastically contract
indicated for spastic detrusor activity
SE: dry mouth, constipation, sedation
Mirabegron MOA?
beta-3 agonist that acts selectively on bladder wall beta receptors to promote bladder storage
**Acts via sympathetic noradrenergic pathway
Bethanechol MOA?
pro-cholinergic medication that increases detrusor activity - promotes bladder emptying by stimulating muscarinic ACh receptors in bladder wall
*Cholinergic S/E: runny noise, hypersalivation, diarrhea
Tamsulosin MOA for bladder use?
alpha-1 blocker that acts in urinary bladder neck to inhibit sympathetic (noradrenergic) action - relaxes smooth muscle to open bladder neck
Duration of anticoagulation in SCI population?
Incomplete: on AC until IPR discharge
Complete, uncomplicated: 8 weeks
Complete, complicated: 12 weeks
Heparin MOA?
activates antithrombin 3, which then inhibits Factor Xa
*Rapid reversal with protamine sulfate
Monitor platelets, risk of HIT
Enoxaparin MOA?
binds to antithrombin III, a serine protease inhibitor, forming a complex that irreversibly inactivates factor Xa
Also reversed with protamine sulfate
Amantidine MOA?
NMDA receptor antagonist and direct dopamine agonist
Neurostimulation agent used to improve arousal
Can lower seizure threshold
Modafanil MOA?
exact mechanism unknown, thought to be related to dopamine re-uptake inhibition
Methylphenidate MOA?
Norepinephrine-dopamine reuptake inhibitor
Useful for ADHD, neurostimulant in stroke/TBI
*does not lower seizure threshold
Donepezil MOA?
Cholinesterase inhibitor that promotes ACh accumulation in the brain (cholinergic)
May be useful neurostimulant in anoxic brain injury, addresses behavior and cognitive symptoms in Alzheimer patients
Valproate MOA?
Voltage-gated Na+ channel blockade; mechanism not fully understood
Can cause excessive sedation; can check blood level
Carbamazepine MOA?
Inhibits Na+ channels on neurons; thus preventing signal transmission along nerves
*Useful for trigeminal neuralgia
Also used as mood stabilizer in TBI pts
Trazodone MOA?
Serotonin reuptake inhibitor that is used as a combination antidepressant sleep-aid
*Risk of serotonin syndrome
Mirtazapine MOA?
Increases central serotonergic and noradrenergic activity
Useful to increase appetite, improve mood and serve as sleep aid
Pyridostigmine MoA?
Anticholinesterase - prevents breakdown of ACh in synaptic cleft
Riluzole MoA?
Blocks glutamate action in the CNS
Prolongs survival by a few months in ALS patients
Medications for SMA treatment?
Nusinerson - alters splicing activity of SMN2 gene so that it produces more SMN protein
Onasemnogene abeporvovec - replaces mutated SMN1 gene, creates functional SMN1 protein
Risdiplam - modifies splicing pattern of SMN2 RNA so cell makes more SMN2 protein
MoA of local anesthetics? (lidocaine, bupivacaine, ropivacaine)
Na+ channel inhibitors, thus inhibiting action potential transmission
MoA of Dalfampridine (ampyra)?
potassium channel blocker that increases ACh release at the neuromuscular junction and in the central nervous system
Improves walking speed in patients with all forms of MS
Which drug in transplant patients can cause AMS including hallucinations?
Tacrolimus (especially at supratherapeutic levels)
Delirium often improves as tacrolimus level falls into therapeutic range
Spasticity medication that is contraindicated w/ IV ciprofloxacin?
Tizanidine
Cipro inhibits cytochrome P450-1A2 resulting in decreased hepatic metabolism of tizanidine - increasing plasma concentration
Medications that increase PT/INR?
sulfonamides, acetaminophen, amiodarone, aspirin, NSAIDs
Medications that decrease PT/INR
Adrencorticoids, antacids, antihistamines, cabamazepine, haloperidol, vitamin C
Which drug class is cyclobenzaprine similar to?
TCAs (first studied as antidepressant)
Rituximab MOA?
binds B-lympcytes CD20 surface antigens and depletes the B cell population
Etanercept MOA?
TNF alpha antagonist
Abatacept MOA?
blocks co-stimulatory molecules and T-cell activation
Anakinra MOA?
inhibits interleukin-1 type receptors
