Drugs Week 2 + Some Trudy Flashcards
Acetylcholine trade name
acetylcholine
Acetylcholine drug class
cholinergic neurotransmitter
Acetylcholine mechanism of action
cholinergic neurotransmitter, rarely used as a drug because effects too generalized - prototypic cholinergic agonist - in periphery cholinergic transmission occurs both with autonomic and somatic NS
Acetylcholine side effects
- v high doses Ach muscarinic effects on heart can be lethal unless muscarinic antagonist present - prolonged ACh at neuromuscular junction at high doses causes tremors and fasciculations which terminate in depolarizing paralysis bc inactivation Na+ channels
Acetylcholine fx
important for normal functioning of both central and peripheral nervous system Muscarinic effects acetyl choline USE GBH Heart- decrease rate and contraction force GI tract- increase secretions and peristalsis decrease sphincter tone Urinary bladder- contract detrusor and relax sphincter Bronchioles- contract, decrease airways, increase secretions Eye- Contract iris, constrict ciliary muscle, open canals of Schlemn, decrease pressure Exocrine glands- increase salvation, lacrimation, sweating (except horse) Blood Vessels- indirect relaxation via increase NO synthesis in endothelial cells Nicotinic effects at neuromuscular junction -contract skeletal muscle Nicotinic effects at autonomic ganglia: - summation of parasympathetic and sympathetic effects, generally sympathetic responses predominant (tachycardia, increase blood pressure, other sympathetic responses)
atracurium trade name
tracrium
atracurium drug class
muscle nicotinic antagonist
atracurium mechanism of action
Acetylcholine receptor non depolarizing blockers (competitive antagonist that binds to acetylcholine receptor but does not create response)
atracurium side effects
- interacts with phenothiazines, local anesthetics, general anesthetics and antibiotics can potentiate activity of neuromuscular blockers - histamine release -> secondary side effects including: allergic rxn, inadequate or prolonged block, hypotension, vasodilation, bradycardia, tachycardia, dyspnea, broncho-laryngospasm, rash, urticaria, and reaction at injection site
atracurium fx
-commonly used as neuromuscular blocker designed to be shorter acting with less ganglionic blockade and histamine release than D-tubocuraine - used as adjunct to general anesthesia to produce muscle relaxation during sx procedures or mechanical ventilation and also to facilitate endotracheal intubation
bethanechol trade name
Urecholine
bethanechol drug class
muscarinic agonist
bethanechol mechanism of action
-direct acting muscarinic agonist (produce only muscarinic effects so parasympathomimetic) - mostly effects GI and bladder - Choline ester
bethanechol side effects
- V+ - cramping - ptyalism (excessive salivation) - anorexia - increased uretheral resistance
bethanechol fx
- increase GI motility - reduce bladder tone (treat atony in dogs, cats, horses) - management idiopathic megaesophagus - increase detrusor tone post urethreal obstruction cats
dantrolene trade name
dantrium
dantrolene drug class
ryanodine recetpor antagonist
dantrolene mechanism of action
decreases amount of calcium released into cytoplasm from sarcoplasmic reticulum by interacting with ryanodine receptor in muscle (ryanodine is involved in Ca2+ release -> muscle contraction) this blocks ryanodine receptor and therefore Ca2+ release
dantrolene side effects
-hepatoxiicity CNS associated signs: - weakness - sedatino - dizziness - headache - GI effects (nausea, V+, constipation) - increased urinary frequency and possibly hypotension
dantrolene fx
-reduces contraction of skeletal muscle - used in malignant hyperthermia
dexmedetomidine trade name
dexdomitor
dexmedetomidine drug class
sedative, alpha-2 adrenergic agonist
dexmedetomidine mechanism of action
inhibits neuronal firing in brain and spinal cord by diminishing release of norepinephrine from presynaptic neuro terminal
dexmedetomidine side effects
-hypotension, bradycardia, poor peripheral perfusion and sedation
dexmedetomidine fx
sedative and analgesic
gabapentin trade name
neurontin
gabapentin drug class
analgesic
gabapentin mechanism of action
- structural analogue of GABA - binds axillary subunit (a2S-1) of voltage-gated Ca2+ channels inhibiting nerve injury-induced trafficking of Ca2+ channels at pre-syn terminals DRG neurons (inhibit Ca2+ channels -> decrease NT release)
gabapentin side effects
- dizziness - somnolence - ataxia - peripheral edema - confusion
gabapentin fx
-recommended first line treatment for neuropathic pain (along with antidepressants and topical lidocaine) - anticonvulsant
ketamine trade name
ketalar
ketamine drug class
glutamate receptor antagonist
ketamine mechanism of action
NMDA receptor antagonist (activate glutamate synapses more likely to be inhibited by dissociate anesthetics bc NMDA-type glutamate receptors in pain pathways that are stimulated more likely to be blocked
ketamine side effects
- strong dysphoric rxn when drug wears off - respiratory depression following high doses - emesis - vocalization - erratic and prolonged recovery - dyspnea - spastic jerking movements - convusions - muscle tremors - hypertonicity -opsithonos - cardiac arrest -seizures - CNS effects
ketamine fx
-dissociative anesthetic - preanesthetic drug (causes dysphoria so use with noradrenergic alpha 2 agonist or benzodiazepine (ie diazepam) - analgesia - amnesia (of sx procedure) - protect brain from excitotoxic cell death during hypoxic episodes - maintain or increase cardiac output
morphine trade name
Avinza, Duramorph, Astramorph, Kadian, DepoDur
morphine drug class
opiod
morphine mechanism of action
- activate opioid receptor -> -inhibition voltage-sensitive Ca2+ channels in presynaptic neuron -> less NT released - activation inwardly rectifying K+ channels (GIRKs) in post synaptic neuron -> membrane hyperpolarization - modulation cAMP-gated K+ channels These activities attenuate neuronal excitability and reduce neurotransmitter release
morphine side effects
- constipation - sedation -dizziness - nausea - V+ - physical dependence - tolerance - respiratory depression Chronic use ->: - tolerance -addiction - opioid-induced hyperalgesia
morphine fx
analgesia
pancuronium trade name
pavulon
pancuronium drug class
muscle nicotinic antagonist
pancuronium mechanism of action
-non depolarizing acetylcholine receptor blocker - binds to acetylcholine receptor, does not produce a response - ammonio steroid
pancuronium side effects
-NO histamine release - some vagal blockade observed bc interactions muscarinic acetylcholine receptors -> possible tachycardia
pancuronium fx
used as adjunct to general anesthesia to produce muscle relaxation during sx procedures or mechanical ventilation and facilitate endotracheal intubation
Phenobarbital trade name
phenobarbital
phenobarbital drug class
barbiturate
phenobarbital mechanism of action
allosteric agonist that binds GABAa receptor, works at allosteric site called barbiturate site and increases Cl- influx
phenobarbital side effects
-lethargy - anxiety/ agitation - depression - polydipsia - polyuria -polyphagia - sedation - ataxia Rarely: - anemia - thrombocytopenia -neutorpenia - hepatic failure cats - can also see weight gain, facial pruritus - do not have liver enzyme issues unlike dogs - coagulopathies - adrenal insufficiency
phenobarbital fx
-anti-convulsant -sedative
pralidoxime (2-PAM) trade name
protopram
pralidoxime (2-PAM) drug class
OP reversal agent
pyridostigmine trade name
none
pyridostigmine drug class
cholinesterase inhibitor
pyridostigmine mechanism of action
-indirectly acting agonist (cholinesterase inhibitor ie anticholinesterase) - carbamylating ester, reversibly inhibits chE for a few hours via covalent modification (carbamylation)
pyridostigmine side effects
cholinergic in nature - GI motility increase - salivation - lacrimation (increase) - abdominal pain - D+ - bradycardia OD: - cholinergic toxicity
pyridostigmine fx
-treatment myasthenia gravis - reversal of some neuromuscular blockers
succinylcholine trade name
quelicin, anectine
succinylcholine drug class
depolarizing nicotinic blocker
succinylcholine mechanism of action
acetylcholine receptor depolarizing blocker; binds to acetylcholine receptor and produces response but rapidly desensitizes the receptor this temporarily blocks further activation of receptor
succinylcholine side effects
- succinylcholine degraded by pseudocholinesterase in serum and bc pseudocholinesterase is synthesized in liver, hepatic damage can decrease the enzyme level in serum causing complications with use succinylcholine - drug interactions: phenothiazines, local anesthetics, general anestertics, and antibiotics can potentiate the activity of neuromuscular blockers
succinylcholine fx
- induction of anesthesia - wildlife capture - Use of these agents without ventilation= malpractice
thiobarbital trade name
thiobarbital
thiobarbital drug class
barbituate
thiobarbital mechanism of action
allosteric modulator of GABAa receptor - acts at allosteric barbiturate site and directly at neurotransmitter receptor site as direct agonist - decreases responsiveness of membrane
thiobarbital side effects
???
thiobarbital fx
injectable anesthetic (short acting)
tramadol trade name
ultram, ConZip, Ryzolt
tramadol drug class
opiod
tramadol mechanism of action
- synthetic analgesic - functions as agonist for MOP (and probably KOP) - inhibits serotonin and norepinephrine reuptake - mainly works on CNS
tramadol side effects
- dizziness - V+ - Nausea - Somnolence - Constipation
tranamdol fx
second line treatments for neuropathic pain
atropine trade name
atropine
atropine drug class
muscarinic antagonist
atropine mechanism of action
-inhibits acetylcholine and other cholinergic stimulants at postganglionic parasympathetic neuroeffector sites - high dose can block nicotinic receptors at autonomic ganglia and NMJ
atropine side effects
- dry mount - increased viscosity of secretions - dysphagia - constipation - V+ - thirst - urinary retention or hesitancy - CNS effects (stimulation, drowsiness, ataxia, seizures, respiratory depression) - Opthamic effects (blurred vision, pupil dilation, cycloplegia, photophobia) - Cardiovascular effects (sinus tachycardia, increased myocardial work, O2 consumption, bradycardia, hypertension, hypotension, arrhythmias, circulatory failure)
atropine function
- antidote for organophosphate intoxication - preanesthetic prevent or reduce secretions of respiratory tract - treat sinus bradycardia, sinoatrial arrest, incomplete AV block - differentiate vagally-mediated bradycardia for other causes - antidote for OD cholinergic agents
Pralidoxime (2-PAM) trade name
Protopam
Pralidoxime (2-PAM) drug class
OP reversal agent
Pralidoxime (2-PAM) mechanism of action
Removes phosphate from serine to reactivate cholinesterase (In OP poisoning phosphate binds to serine -> permanent inactivation of enzyme unless 2-PAM reverses this because next step is loss of alkyl group and then v hard to reverse)
Pralidoxime (2-PAM) fx
organophosphate poisoning reversal
Pralidoxime (2-PAM) side effects
- rapid IV inject can cause tachycardia, muscle rigidity, transient neuromuscular blockade, and laryngospasm
