Term
| Indications for use of pre-anesthetic medications: |
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Definition
1. to relax, calm, or sedate an apprehensive animal
2. to chemically restrain an aggressive animal
3. to provide analgesia
4. to provide muscle relaxation
5. to decrease dose req of agents with a narrow safety margin
6. to decrease incidence of adverse effects assoc with certain agents or procedures
7. to help provide for smooth recovery
8. not every animal needs |
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Term
| Classes of drugs used as pre-anesthetic agents: |
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Definition
-anticholinergics
-tranquilizers
-alpha 2 adrenergic agonists
-opioids
-neuroleptanalgesics
-dissociatives |
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Term
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Definition
-increase SA node rate before increasing AV node rate, can lead to a transient second degree AV block, most often seen after IV administration
-not routinely used in ruminants or equine as may be decreased intestinal motility and ileus potentially leading to colic
-in ruminants, the anticholinergics decrease thin secretions leaving thick viscous secretions that may obstruct airways |
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Term
| Mechanism of action of anticholinergics. |
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Definition
| competitive inhibition of acetylcholine in PS cholinergic, muscarinic, receptors |
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Term
| Indications for use of anticholinergics: |
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Definition
-prevention of vagally-induced bradycardia, which may occur secondary to: actions of other agents such as opiods, surgical procedures involving traction on eye, neck, or abdominal viscera
-pre-existing bradycardia
-decrease excessive salivation as may be seen with dissociative agents or in nervous dogs or cats |
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Term
| Effects of anticholinergics: |
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Definition
-tachycardia
-decreased secretions
-bronchodilation
-decreased GI motility |
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Term
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Definition
-tertiary amine, crosses BBB and placenta
-can cause tachyarrhthmias
-rapidly hydrolyzed by atropine esterase enzymes (rabbits, rats, goats)
-blockade of papillary constrictor m and ciliary m produces long-lasting mydriasis and cycloplegia (caution with glaucoma) |
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Term
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Definition
-quarternary ammonium
-d/n readily cross BB or placenta
-may cause less tachycard |
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Term
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Definition
-calming
-d/n produce reliable sedation or chemical restraint
-DO NOT provide analgesia |
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Term
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Definition
-major tranq
-most commonly used tranq in vet med |
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Term
| TQ: Mechanism of action of Ace |
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Definition
-antagonism of dopamine and serotonin neurotransmission in limbic system and basal ganglia
-may also block central NE and Epi transmission
-peripheral action in blockage of alpha 1 vascular receptors leading to vasodilation |
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Term
| TQ: Indications for use of Ace |
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Definition
-as a pre-anesth to calm and reduce anxiety
-used before anesthesia to smooth induction and recovery
-to potentiate effects of other agents when used in combination |
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Term
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Definition
-contraindicated in animals with hypovolemia, hypotension, or shock
-peripheral vasodilation caused by ace exacerbates hypotension
-have been many reports of severe bradycardia and collapse in dogs after admin
-Boxers more prone to bradycardia after ace
-can be acute collapse when ace given, especially IV, to extremely excited or stressed animals |
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Term
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Definition
| -good tranq for use in healthy patients for calming before anesthetic induction and for quiet recovery |
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Term
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Definition
-can cause paraphymosis (permanent penile prolapse) in stallions (reverse with benztropine)
-minimal resp depressive effects |
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Term
| TQ: Onset of action, Duration of action of Ace |
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Definition
-onset: slow 30-45 min IM, 5-15 min IV
-duration: 3-8 hours (may be longer in young, old, hypothermic, or debilitated animal)
-provide warmth for recovery |
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Term
| TQ: Ace-reversal other info. |
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Definition
-no reversal agent
-highly protein-bound (more unbound drug in hypoproteinemic animals)
-metabolized by liver and excreted via kidney
-some antiemetic, antihistaminergic, and antiarryhthmic properties |
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Term
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Definition
-minor tranq
-often used in combination with other agents, may cause dysphoria if used alone
-may potentially cause aggressive behavior if used alone in young, healthy animals |
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Term
| Benzodiazepines mechanism of action |
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Definition
-via potentiation of inhibitory NT GABA
-used as part of premed with other agents to potentiate their effects
-can be used alone to provide mild restraint in moribund animal or in neonatal foals, calves, and pigs |
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Term
| Effects of Benzodiazepines |
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Definition
-anti-anxiety, euphoria, dysphoria, anti-convulsant activity, m. relaxation, ataxia
-wide safety margin
-can be used in most spp but has wide individual variations of effect
-commonly used as part of IV induction technique
-may cause mild resp depression
-schedule IV
-can be reversed |
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Term
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Definition
-trade name: Versed
-Water soluble base makes excellent absorption IM or SC
-useful agent to use in comb with ketamine as premed for cats
-useful in combinations with opiod in neonates or debilitated geriatric patients as neuroleptanalgesic
-duration: 1-2 hours |
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Term
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Definition
-Valium
-propylene glycol makes IM injection painful and absorption unpredictable
-best injected IV
-propylene glycol is implicated in causing hypotension following rapid IV bolus injection
-give slowly IV and flush with fluids to decrease risk of phlebitis
-rate of metabolism is variable depending on age and the spp |
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Term
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Definition
-trade name: Romazicon
-a benzodiazepine antagonist
-not a controlled drug (expensive) |
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Term
| Alpha 2 adrenergic agonists |
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Definition
-mechanism of action: central pre-synaptic inhibition of NE release
-vagomimetic actions, peripheral activation of post-synaptic alpha receptors in vasculature, pancreas GI tract, and other areas |
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Term
| A2AA: Indications for use |
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Definition
-pre-anesthetic sedative/analgesic/muscle relaxation in healthy animals
-to provide sedation for minor dx or sx procedures in healthy animals
-used in combination with dissociatives for short duration injectable procedures in healthy animals |
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Term
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Definition
| -sedation, analgesia, m. relaxation, bradycardia, widespread peripheral vasoconstriction, pancreatic insulin inhibition, resp depression, hypertension followed by hypotention, decreased CO, diuresis due to ADH inhibtion, and vomiting |
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Term
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Definition
-use cautiously in all animals with CV compromise
-can cause profound bradycardia and 1st and 2nd AV block
-monitor HR and rhythm closely
-avoid using in animals with pre-existing bradyarrhth or AV block
-reflex bradycardia in response to vasoconstriction leads to hypertension
-use of anticholinergics is controversial as hypertension caused by A2AA is compounded by tachycardic effects of anticholinergics
-can cause a biphasic effect on blood pressure as initial vasoconstriction leads to hypertension and then hypotension can develop secondarily to centrally mediated reductions in CO |
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Term
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Definition
-can produce an immune-mediated pulmonary edema and hypoxemia in sheep
-highly stressed animals may not become sedate and may in fact become more excited after drug administration
-avoid their use in debilitated, very young, or very old animals
-ruminants very sensitive to these agents, use lower doses
-swine d/n respond reliably to A2A, use them in combination with other agents
-can cause resp depression and hypoxemia
-can cause aerophagia in some dogs |
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Term
| Other effects A2AA (cont) |
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Definition
-causes insulin inhibition and hyperglycemia so not use in diabetics
-not controlled and are reversible
-receptor-binding or selectivity ratios A2 to A1 for commonly used agents: xylazine (160:1), Detomidine (260:1), Romifidine (340:1), Medetomidine (1620:1), Dexmedetomidine (1620:1) |
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Term
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Definition
-Rompum
-One of three most commonly used restrain-sedative drugs for horses and cattle
-can be given IM, SC, IV, or lingual (most common IV horses)
-rapid onset, short duration
-horses can be sedate (can still kick)
-can use alone or with butorphanol in horses
-can be used in healthy small animal patients
-best to avoid the use of xylazine, thiopental, and halothane in small animals due to potential for cardiac arr and cardiac arrest
-freq used in comb with ketamine for injectable anesthesia or induction in small and large animals
-due to increased myometrial tone and intrauterine pressure not recommended for use in animals in last trimester of preg
-can be used epidurally to produce regional analgesia |
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Term
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Definition
-Dormosedan
-more potent/selective than xylazine
-can use in horses
-common used for standing restraint in horses-produces more reliable sedation than xylazine
-can be used as pre-med but monitor heart rate closely
-longer duration than xylazine (40-60 min) |
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Term
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Definition
-Sedivet
-horses for sedation and standing restraint
-potency is greater than xylazine, less than detomidine
-appears to cause less ataxia than other A2A
-duration of action (30-60 min) |
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Term
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Definition
-Domitor
-mixture of dextro and levo-enantiomer
-very potent (50-100X > xylazine)
-approved for use in healthy dogs, can be used in cats and zoo animals |
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Term
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Definition
-profound effects, long-lasting sedative, analgesic, and adverse effects
-duration is > 2 to 3 hours
-used as chemical restraint-sedative for minor dx/sx procedures
-can be combined with opioids to decrease dosages of both drugs and provide profound neuroleptanalgesia
-when used as pre-med will greatly reduce requirement for other agents, be cautious when administering other agents
-can be used with ketamine for injectable anesthesia |
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Term
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Definition
-Dexdomitor
-MOST SPECIFIC AND SELECTIVE A2A
-compared to medetomidine, dex has only dextro-enantiomer
-approved IM and IV in dogs, IM in cats
-longer lasting analgesia as compared to medetomidine
-more potent so can use a lower dose than medetomidine |
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Term
| A2ANTAGONISTS: Yohimbine, Tolazoline, Atipamezole |
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Definition
-antagonize effects of of alpha 2 agonists
-Yohimbine less eff
-side-effects: tachycardia, systemic and pulmonary hypertension, anxiety
-reversal may take minutes (may need repeat)
-atipamezole is most selective and most effective (marketed to use wtih medetomidine)
-Caution with tolazoline (can cause collapse and sudden death in llamas)
-Tolazoline works well in cattle to reverse effects of xylazine |
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Term
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Definition
-MOA: binding to specific opiate receptors in brain, spinal cord, and peripheral sites to prevent transmission of nociceptive info
-used as pre-meds to provide preemptive analgesia, sedation |
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Term
| Opiods effects, indications |
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Definition
-effects: analgesia, resp depression, hypoventilation, bradycardia, nausea, v, cough suppression, occasional dysphoria, and narcosis
-very good agents in very young, old, and debilitated and most ill animals
-used for pre-meds, intra-op analgesia, and post-op analgesia, can be used in a variety of ways
-use as pre-med or intra-op can decrease amount of other agents and inhalants needed
-vomitting=common when given IM
-can cause release of ADH
-controlled
-can be reversed |
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Term
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Definition
-excellent analgesia with minimal CV compromise
-can cause bradycardia
-may need an anticholinergic to tx the bradycardia
-can cause mild positional hypotension, avoid sudden postural changes
-morphine and meperidine can cause histamine release if administered IV, give slowly if have to give IV
-histamine release can cause hypotension secondary to vasodilation |
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Term
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Definition
-can cause dose-dependent resp depression (will see decrease in rate and tidal volume)
-potentiated by gen anesth, may need intermittent positive pressure ventilation (IPPV)
-dogs sometimes pant excessively after opioids, either due to thermoregulatory center disruption or initial stimulation of resp center |
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Term
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Definition
-sedation can occur in dogs and human, not usually seen in other spp
-Euphoria and dysphoria can occur, more common in cats and horses (used with tranqs)in these spp
-use cautiously in animals with head trauma when CSF pressure is unknown or questionable (hypovent from drug can lead to increase CO2 level, can cause cerebral vasodilation and subsequent increase in CSF pressure
-may need to support ventilation to keep CO2 level in normal range
-may see hyperthermia post-op in cats
(esp with mu agonists) |
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Term
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Definition
-excellent analgesia, dose-dependent resp depression
-can cause vomitting
-effects following IM injx occur in 5 to 15 min, duration 3-6 hours
-histamine release when given IV
-used to provide analgesia in several spp
-can cause dysphoria seen in prolonged vocalization, pacing, agitation
-combine with tranq (schedule II drug) |
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Term
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Definition
-Nurmorphan
-10 times more potent than morphine
-effects begin 5-10 min after IM
-administration and duration is 1-3 hours
-can safely give IV (no histamine release)
-expensive and no vet label
-excellent pre-med for pediatric, geriatric and debilitated dogs when prolonged sed not desired
-when cmobined with a tranq such as midazolam-good pre-med for old, sick cats
-can cause dysphoria and vocalization |
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Term
| Mu agonists:Hydromorphone |
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Definition
-Dilaudid
-similar to oxymorphone
-duration 1-3 hours
-safe to give IV (no histamine release)
-seems less likely to cause vomiting than morphine or oxymorphone
-can cause post-op hyperthermia in cats |
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Term
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Definition
-Demerol
-histam release if given IV
-only 20% as potent as morphine
-effects begin 5-10 min after IM injx, duration is 1-2 hours
-can cause tachycardia via atropine-like actions
-useful for short-term procedures such as castration, dental cleaning
-can be used in IM in large animals for analgesia |
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Term
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Definition
-very short acting (give IV)-onset 5 min, duration 30 min
-100 times as potent as morphine
-no histamine release when given IV
-commonly used as CRI for analgesia
-also comes as transdermal patch
-schedule II |
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Term
| Partial mu agonist: buprenorphine |
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Definition
-Buprenex
-slow onset after IM or IV injx, 20-30 min
-long duration (3-6 hours)
-moderate to good analgesia (not as profound as full mu ag)
-binds avidly to mu receptors and difficult to reverse
-works well in cats and can be given transmucosally
-schedule 5 |
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Term
| Kappa agonist/mu antagonist: Butorphanol |
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Definition
-Torbugesic
-mild to moderate analgesia with mild resp depression
-can be given IM, SC, PO, IV
-onset following IM: 5-7 min, duration 45 min-1.5 hours
-d/n reliably cause sedation when used alone unless animal already calm or debilitated
-more reliable sedation is achieved when combined with tranq or sedative
-not as potent an analgesic as mu agonists |
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Term
| Kappa agonist/mu antagonist: Nalbuphine |
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Definition
-Nubain
-not routinely used as pre-med
-effects are mild analgesia, min to no sedation, min resp depression
-duration: 1-2 hours
-not controlled
-mu antagonist effect of butorphanol or nalbuphine can be used to reverse effects of mu agonists while maintaining some analgesia (so called "partial reversal") |
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Term
| Opioid antagonists: Naloxone |
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Definition
-Narcan
-reverses all effects of opioids, mu, and kappa agonists
-use in overdose situations, arrest, or when adverse effects are pronounced
-bolus admin can lead to tachycardia, hypertension, and pulmonary edema
-give slowly IV or IM
-duration 30-45 min, therefore, re-narcotization may occur with longer-acting agonists |
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Term
| Opioid antagonists: Naltrexone |
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Definition
-potent and longer duration
-used mainly to reverse effects of potent opioids used to capture zoo and game animals |
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Term
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Definition
-comb of opioid with tranq or A2agonist
-comb produces synergistic actions
-used to provide chemical restrain, greater degree of sedation and analgesia
-numerous combs that can be used depending on temperament of the animal, desired effects, and the properties of the agents |
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Term
| Neuroleptanalgesics in dogs and cats: Ace/opioids |
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Definition
-used to provide sedation and analgesia in healthy active, dogs, esp in norther breeds, biters
-used to provide analgesia in cats, sedation variable
-not recomm in debilitated animals due to potential for hypotension
-may need an anticholinergic if bradycardia
-can give IV (if not using morphine or meperidine) |
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Term
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Definition
-used to provide analgesia, variable sedation
-good for use in geriatric, pediatric, and debilitated animals
-both agents reversible |
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Term
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Definition
-used for chemical restraint in aggressive animals
-useful for minor sx or dx procedures
-very likely to cause bradycardia
-not recomm in debilitated animals
-both agents can be reversed |
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Term
| Neuroleptanalgesics in horses |
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Definition
-combinations of A2agonists and opioids are used as pre-meds, to provide standing restrain and for minor dx and sx procedures
-Xylazine wiht butorphanol: used for pre-med prior to induction or standing restraint (duration 20 minutes)
-Xyl/morphine: Give xylazine first!!, produces profound sedation and analgesia, morphine effects last longer than xylazine, so may need to repeat xylazine
-give morphine slowly
-Detomidine with butorphanol-more profound effect and longer duration than with xylazine |
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Term
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Definition
-produce dose-depend actions ranging from mild catatonia to chemical restraint to general anesth
-used in wide variety spp
-wide safety margin
-most often used in comb with other drugs due to side effects
-MOA: interference with transmission of nervous impulses between limbic system and thalamocortical areas of brain leading to dissoc between subconscious and conscious systems. Non-comp antag of NMDA receptors.
-indications: pre-med to restrain cats, aggressive dogs, swine, exotics prior to induction
-as an IV induction agent prior to inhalant anesth
-used IM or IV for injectable anesth (Not IM in horses)
-not used for standing restrain in horses |
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Term
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Definition
-sub-anesth doses can be given as a CRI for analgesia
-well absorbed, does sting IM
-can be given orally
-can cause excessive salivation, may use an anticholinergic to prevent this
-very poor m. relaxation
-can have slow, bizarre recovery, may need tranq to smooth recovery
-primarily renal excretion in cat
-may cause resp depression and apneustic breathing, IV bolus may lead to apnea
-Analgesa not sufficient for severe visceral or orthopedic pain
-schedule III
-not reversible |
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Term
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Definition
-maintenance of eye movement, increased muscle tone, increased sympathetic output, increased intracranial and intraocualr pressure
-CV effects: can cause increases in HR, contractility, BP, CO, and myocardial oxygen demand
-CNS effects: increases CSF pressure, therefore avoid in animals with known or suspected increased intracranial or intraocular pressure
-can cause seizure-like activity in dogs, use with benzodiazepines to prevent this |
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Term
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Definition
-commonly used as pre-med, chemical restraint, and anesthetic in cats, swine, and exotic spp
-used as IV induction agent in several spp
-m. tone maintained and analgesic effects limited so combined with tranq, sedatives, and opioids to provide relaxation and enhance analgesia
-painful IM or SC
-cats may become hyperthermic, agitated, dilated pupils, flushed ears, monitor body temp (small dose ACE may help) |
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Term
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Definition
-Ketamine+ace or midazolam+hydromorphone or oxymorphone or butorphanol+/- atropine will provide dose-dependent chemical restrain or anesthesia
-used IM for injectable anesthesia or pre-med
-ketamine+xylazine or medetmidine or dexmedetomidine for injectable anesthesia or pre-med. effects last 15-20 min with xylazine, 30-60 min with medetomidine
-Ketamine+diazepam for IV induction or quick procedures (l0 min duration) |
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Term
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Definition
-ketamine+diazepam IV for induction or inj anesthesia
-effects last 10-20 min
-can add Ace to smooth out recovery |
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Term
| Ketamine (horses and ruminants) |
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Definition
| -after pre-med, ket+diaz or GG IV for inductino or short anesthesia (lasts 10-15 min) |
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Term
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Definition
-ket + xylazine IM for dose-dependent chemical restraint to anesthesia
-can give additional doses of ketamine IV if vein is accessible |
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Term
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Definition
-Telazol
-1:1 mix (dissoc-Til, BZ-zol)
-Zolazepam is added to improve m relaxation
-comes in a dry mixture, reconstitute with sterile saline or sterile water
-once it is rehydrated, loses potency over a period of days and will become light brown
-use lower doses than package
-used similarly to ket, IM chemical restraint in cats, vicious dogs, swine, exotic spp
-IV induction agent in cats, dogs, horses, rum
-cats may have a prolonged recovery due to slow metabolism of zolazepam
-dogs may have rough recovering dur to slow metabolism of tiletamine |
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