Preanesthetic medication Flashcards

Question

Relative contraindications of phenothiazine

Answer 1

Breeding stallions- penile prolapse BOXERS- may exacerbate underlying arrhythmias Also avoid in severely debilitated, neonates, geriatrics, preexisting hypotension (blood loss, shock, dehydration), CHF, liver disease, CRF Related to vasodilation and resultant hypotension Always use caution when sedating brachycephalic breeds

Answer 2

Can also use alone for anti-anxiety and minor restraint Used in combination with other drugs for pre-anesthesia There is a mg/kg dose AND a maximum dose Increasing the dose does NOT increase sedation but does increase hypotension due to peripheral vasodilation Works better if not already excited; excitement can decrease the effect Lasts 4-8 hours Do not combine with dexmedetomidine No reversal. If overdose, provide supportive care Support BP-fluids Increase the sympathetic response

Answer 3

Azaperone/Stresnil@ Drug class: butyrophenones (similar to phenothiazines) Only used in pigs Very unpredictable results in other species Blocks dopamine and norepinephrine activity in the CNS

Answer 4

Decreases aggression/fighting during weaning and mixing Premedication and sedation (castrations) Antiemetic Decreases malignant hyperthermia Potentially fatal genetic condition; increased metabolic rate and muscle activity in response to isoflurane, transport/handling stress Most commonly occurs in pigs

Answer 5

Ex. diazepam (Valium@), midazolam (Versed@) Controlled (schedule IV of the controlled drugs and substances act) Most not labelled for veterinary use therefore an example of ELDU Injectable and oral (tablets) formulas available

Answer 6

Antianxiety and calming Anticonvulsant activity Disorientation and excitement in young, healthy dogs Dysphoria and aggression in cats Muscle fasciculation in horses Ataxia in recumbency in large animals Few cardiopulmonary effects Skeletal muscle relaxation No analgesia

Answer 7

Reversal → flumazenil

Answer 8

Increase GABA levels in the brain GABA is an inhibitory neurotransmitter

Answer 9

As part of balanced anaesthesia Premed to smooth induction and recovery Can combine with ketamine for induction Other common indications Antianxiety to sedation; behavioural modifier Anticonvulsant for treating seizures Skeletal muscle relaxant (including urethral relaxation)

Answer 10

Minimal CV effects at appropriate dose Dose cause dose-dependent resp depression Smoother induction and recovery Decreases amount of inhalant GA required Increase skeletal muscle relaxation

Answer 11

Reversible drug class In the event of overdose or adverse reaction, can give the reversal agent (aka antagonists or antidotes)

Answer 12

Sedation is not always reliable when used alone in animals Dysphoria/excitement can occur May unmask latent aggression in some animals (animals lose inhibitions)

Answer 13

Muscle fasciculation Weakness, ataxia Do not give alone except for seizures in adults

Answer 14

AVOID in pregnancy/caesarean Will cross the placenta Causes similar to FLOPPY BABY SYNDROME Skeletal muscle relaxation in the neonate Asphyxiation form relaxation of resp muscle

Answer 15

Benzodiazepine Commonly used Dog, cat, horse, pig

Answer 16

Anticonvulsant for emergency treatment of seizures Antianxiety (noise phobias) at lower dose Sedation in some patients at higher dose Must be used in combination with other drugs in cats and horses (and some dogs) or may cause excitement Skeletal muscle relaxant Relaxes urethral sphincter (blocked cats and dogs) Can mix with ketamine for induction (KetVal)

Answer 17

Inexpensive Can be administered by many routes: IV solution- painful/unreliably absorbed if given IM/SQ Can give intrarectal if seizing patient Also available as oral tablets Dose varies depending on the route Lasts 30 min - 2h May cause a prolonged hangover effect Historically used as appetite stimulant in cats- doesn't really work-risky

Answer 18

Controlled drug Not water soluble Will form precipitate if mixed with other drugs Never use if precipitate forms Only exception is KETAMINE (KetVal) Store IV solution in glass containers Drug binds to plastic with time Keep from light Flush IV lines immediately after administering Binds to plastic and will form precipitate if still present in line/verin when drug is administered

Answer 19

Contradiction for caesarean Floppy baby syndrome Depressed, poor muscle tone, excessive sedation Aggressive dogs Can bring latent aggression Using alone in horses Excitement and ataxia Cats Can cause sudden liver failure- increase risk with increase doses Therefore avoid use as an appetite stimulant

Answer 20

Benzodiazepines Very similar to diazepam Easier to use, but more expensive

Answer 21

Twice as potente Shorter acting Compatible with many agents as it is water soluble Can give IM, SQ, IV CANNOT use alone Not used as anticonvulsant

Answer 22

Antagonsit

Answer 23

Reversal agent (aka antagonist) for benzodiazepines including diazepam and midazolam

Answer 24

Binds to and blocks GABA receptors More attraction for the GABA receptor then the benzodiazepines Therefore, knocks of any benzodiazepine drug already bound to the receptor Little to no effect on its own Solemn used because $$$$ and short duration of action of diazepam/midazolam

Answer 25

Dose dependent sedation that can be profound Analgesia Agitation or aggression when touched Reaction to loud noises Muscle tremors in horses Cattle often lie down Initial hypertension, bradycardia, and pale MM followed by hypotension, decreased cardiac output, and a little further decrease in the heart rate Severe decrease in heart rate, BP, cardiac output, and tissue perfusion especially when high doses are given Respiratory depression that can be severe Muscle relaxation Vomiting in cats and dogs Adverse GI effects (bloat and colic) Hyperglycemia Hypothermia Increased urination Premature parturition in cattle Horses may sweat

Answer 26

Xylazine (Rompun@) Detomidine (Dormosedan@) Romifidine (Sedivet@)

Answer 27

Dexmedetomidine (Dexodomitor@)

Answer 28

Drugs bind to alpha-2 adrenergic receptors Activation of alpha 2 receptors causes inhibition of release of norepinephrine and dopamine Decreases overall sympathetic response Metabolized by the liver; excreted by the kidneys

Answer 29

Overall CNS depression Decreased overall ability to respond to stimuli This action is enhanced if given together with an opioid or other sedative or tranquilizer Decreases sympathetic response Bradycardia- consistent, immediate, significant; as low as 12 bpm in a large dog Resp depression Increases parasympathetic nervous system Increased GI motility (except in ruminants)

Answer 30

Rapid and reversible sedation Mild analgesia on own Can be used for neuroleptanalgesia Occurs when alpha-2 agonist is combined with an opioid and given at a fairly high dose A state of lack of awareness associated with very heavy sedation combined with strong analgesia Used for minor procedures e.g. suturing lacerations in horses Centrally-mediated muscle relaxation

Answer 31

Severe hypotension Can hyperventilate on room air Possible arrhythmias with some of the older drugs Increased risk if given too fast IV Increased risk if also given atropine Ataxia Cattle can become recumbent, decreased rumen motility, risk of bloat and may cause abortion Horses can become reactive to stimuli if give alone- noise, touch Emesis in cats

Answer 32

Related to significant bradycardia Decreased pulse, MM become very pale Do not use with acepromazine in small animals

Answer 33

Decreased RR and resp volume Enhances the resp depressant effect of other sedatives and anesthetics RESPIRATORY DISTRESS IN BRACHYCEPHALIC DOGS Ruminant very sensitive to resp effects

Answer 34

Avoid or use extreme caution in pediatrics, geriatric Avoid if severely dehydrated, in shock, cardiovascular disease, severe resp disease, or severe renal disease Avoid if advanced liver disease Avoid or use extreme care with acepromazine Acpreomazine→ severe hypotension from combination of bradycardia and vasodilation; will plummet the BP and there is no way to bring it back other then reversal However it can be fail safe group IF you have reversal on hand MONITOR! MONITOR! MONITOR!

Answer 35

IM (15-20 min onset), IV (1-3 min onset) Duration of sedation is 30-60 min Don't give IV too fast or will enhance the resp and cardiac depression effects When using IV, should “give to effect” only until desired degree of sedation is achieved Avoid SQ Very lipophilic; drug will bind to fat and absorption will be unpredictable (can severely delay effect) Decreased effect if stressed or fearful

Answer 36

Equine and bovine Premed “Standing sedation” -For castrations, wound repairs, caesareans Sedates animal without becoming recumbent Colic -Excellent visceral analgesia 30 min of analgesia if given as an epidural Part of “Triple Drip” -Injectable GA, to be discussed with ketamine Two concentrations 20mg/ml or 100mg/ml -Lower concentration in cattle b/c of increased rep and GI effects IV “to effect” -IV has more pronounced heart and resp effects IM -Onset of action occurs 10-15 minutes after Im injection -Duration of action is approx. 30 min Epidural -Visceral analgesia Often combined with an opioid (ex. butorphanol) or valium for better sedation and longer duration

Answer 37

Cattle require 1/10 of dose compared to horse -Even at recommended dose can have severe resp effects, cause GI stasis (i.e., bloat) risk of aspiration pneumonia Horses -Sweating -Ataxia, wide-based stance -Horses can become excited if used alone -Never given intra-arterial in horse; will cause excitement/seizure/collapse -Avoid in neonatal foals as the lowered HR cannot maintain blood flow

Answer 38

Alpha2 adrenergic agonist labeled for horses

Answer 39

Similar to xylazine Visceral analgesia Give slowly IV to effect Can give alone or with opioid Severe hypotension and bradycardia Twice the duration and stronger sedation Used for standing sedation Never use with IV sulphonamides→ heart failure

Answer 40

Labelled for horses Similar to xylazine, detomidine Fast acting, long lasting Severe hypotension and bradycardia Sedative or pre med Can use at low dose Anxiolytic with minimal ataxia

Answer 41

Small animal Sedation (60-90 min); analgesia (30 min) Sedation Hip rads, minor procedures (with local anesthetic), quills Premed Sedation and pre-emptive analgesia On going sedation if given as CRI

Answer 42

Usually given in combination with opioid Better analgesia Better sedation Dresses the mg/kg dose of dexmedetomidine required→ decreases adverse side effects Most commonly with butorphanol or buprenorphine Will see more resp depression is combined with hydromorphone

Answer 43

The label dose is 10x to 20x what is used in clinic Label dose is intended for heavy sedation with dexmedetomidine alone When combined with opioids and/or with balanced anesthesia, only use at 1/10 to 1/20 the labelled dose Is also labelled for indication at higher doses (not usually done) As animal size increases, the mg/kg dose decreases

Answer 44

IM takes 15-20 min onset time NEVER give SQ- drug deposits in fat and releases unpredictably Give IV to effect Dog only Do NOT give to rapidly, can stop breathing 1-3 min onset Can give ½ IM, wait 15 min, give remainder IV to effect

Answer 45

Profound bradycardia and resp depression (much more noticeable in dogs) Monitor HR and BP HR will drop significantly; 16 (large K9), 40 (small K9) Monitor BP and pulse strength Monitor MM Will be pale; should never be cyanotic Monitor oxygenation Extend neck Place on flow-by 100% O2 if available Place IV catheter If in doubt, place ion IV fluid support

Answer 46

Do NOT use with atropine -Heart block, heart failure Extreme caution of avoid with acepromazine -Profound hypotension Extreme caution when followed by isoflurane in cats -Iso causes more extreme vasodilation then acepromazine Avoid if hypotensive dehydrated, geriatric, debilitated

Answer 47

Reversal Reversals have a greater affinity for receptor then the agonist drug

Answer 48

Yohimbine (Yobine®) Tolazoline (Tolazine®)

Answer 49

Atipamezole (Antisedan®) Designed so you give equal VOLUME as Dexdomitor® for complete reversal

Answer 50

Effects specific to alpha2 agonist- does not affect other drugs Reversal of the sedative, cardiovascular AND analgesic effects of the corresponding agent Few adverse effects at clinical doses, but significant adverse effects if too much is given by increasing sympathetic tone GI, neurologic, and cardiovascular effects Excitement, muscle tremors, hypotension, tachycardia, salivation, vomiting, diarrhea

Answer 51

Analgesia -Strongest analgesics available in vet med Preanesthetic -Pre-emptive analgesia – giving before pain occurs results in less post op analgesia required and shorter recovery times -Sedation -Decrease total dose of GA required Anesthetic induction -At higher doses, some opioids can produce unconsciousness (uncommon)

Answer 52

Majority have wide margin of safety at therapeutic dose (Higher Potency → Lower Therapeutic Index)

Answer 53

Metabolized by liver with renal excretion, therefore Caution in very young, very old, debilitated Caution in very ill (including head trauma, shock, HBC) Caution if respiratory system is compromised

Answer 54

A profound state of sedation and analgesia Induced by simultaneous administration of an opioid and a sedative Ex. Dexmedetomidine + hydromorphone; xylazine + fentanyl Commonly given for minor procedures or indication Causes CNS depression to state of borderline unconsciousness Can be aroused by extreme stimulation, noise

Answer 55

IM SQ IV PO Rectal Transdermal Subarachnoid Intraarticular (joints) Epidural Neurolepetangelasia , when given IV, must be done so slowly to avoid CNS stimulation

Answer 56

Drugs work by binding to opioid receptors Although opioid receptors found on neurons throughout the body, analgesic and sedative effects are primarily the result of their action on receptors located in the brain and spinal cord Brain- sedation and analgesia Spinal cord-analgesia Smooth muscle of the rep tract, GI tract, urinary tract

Answer 57

Mu (μ) Kappa (κ) Delta (δ)

Answer 58

Supraspinal analgesia Moderate to severe pain Sedation Resp depression Bradycardia Miosis (mydriasis in cats) Hypothermia (hyperthermia in cats) Euphoria /dysphoria GI stasis (constipation) Urinary retention CRTZ (chemoreceptor trigger zone) for vomiting Antiemetic at the vomiting center

Answer 59

Spinal analgesia Mild to moderate pain Miosis Mild sedation Little resp depression Diuresis

Answer 60

Pure agnostic Partial mu-agonist Agonist-antagonist Pure antagonists

Answer 61

Opioids are placed into “classes” based on which receptor they bind and whether binding causes the receptor to be turned on (agonist), partially turned on (partial agonist) or turned off (antagonist)

Answer 62

Drugs bind to and turn on the mu-receptor May also turn on kappa-receptor Provides the best analgesia (treats moderate to severe pain) Mu-antagonist provides the best analgesia. Drugs with a higher affinity for the mu-receptor provide more analgesia Also produces sedation Highest risk of addiction Morphine, hydromorphone, oxymorphone, fentanyl, meperidine, hydrocodone, tramadol

Answer 63

Side effects as listed for the mu receptor (resp depression, GI stasis, hypothermia, occasional hyperthermia in cats); analgesia and sedation are better if also has kappa activity

Answer 64

Binds to and partially activates the mu-receptor

Answer 65

Less analgesia Less resp depression Less GI stasis Less euphoria Less hypothermia

Answer 66

Indicated for slight to moderate pain Also used to “partially” block the effects of a pure mu-agonist that is given at the same time; i.e., acts as a partial reversal Buprenorphine (partial mu-agonist; kappa antagonist)

Answer 67

Simultaneously turns on kappa-receptor (kappa-agonist) while blocking mu-receptor (mu-antagonist)

Answer 68

Mild analgesia Sedation Less resp depression and less GI effects than the pure or partial agonists May cause dysphoria

Answer 69

Can be used to “completely block” either mu-agonist or partial mu-agonist activity Butorphanol (kappa-agonist; mu-antagonist)

Answer 70

Binds to both mu-receptors and kappa-receptors but does not produce any activity Effectively acts as a block “Reversals” Naloxone Naltrexone Direnorphine (M-50) is the reversal agent specifically created for etorphine (M-99)

Answer 71

Resp depression Most common cause of death in case of OD Centrally-mediated; decreases RR and tidal volume Also inhibits the CO2-drive that stimulates breathing Ventilation should be monitored and O2 available Bradycardia Hypothermia in all species Occasional hyperthermia in certain cats is due to a mu-receptor response especially hydromorphone and can be fatal if not treated Caution using in patients with brain trauma or cerebral edema; can increase brain swelling Sedation

Answer 72

Vomiting GI stasis (constipation) Dysphoria, excitement, hallucinations, startle response in cats Addiction

Answer 73

Activates the chemoreceptor trigger zone in the brain Often with first dose of mu-agonists in healthy pain free animals Can block/decrease with acepromazine or diazepam

Answer 74

More likely with chronic use Avoid or caution in colic, bloat, FB surgeries (enterotomies)

Answer 75

Mu-receptor mediated Receptor down-regulation means may need to increase dose or dosing frequency to manage chronic pain

Answer 76

Variable effects may or may not occur depending on the specific opioid, dosage, route of administration and species Antitussive (codeine, hydrocodone, butorphanol; to treat cough) Vomit (apomorphine; IM hydromorphone) Diarrhea and flatulence Miosis in dogs; mydriasis in cats and horses Excitement, dysphoria, whine/bark (dogs), increased motor activity (horse), increased sensitivity to noise Hypotension/hypertension Changes in urination Excess salivation Panting in dogs Hyperthermia in cats Sweating in horses

Answer 77

Morphine Fentanyl Hydromorphone Methadone Meperidine Sufentanil Cerfentanil

Answer 78

Mu and kappa agonist Indications “Opioid standard of reference) All other opioids are compared to morphine Mild to moderate sedation dose dependant Analgesia for moderate to severe pain

Answer 79

IV, IM, SQ, PO, intra articular, epidural Duration of action 3-4 hours

Answer 80

Excitement or dysphoria in cats, horses Mydriasis in cats, horses Drowsiness in dogs Severe resp depression with high doses Nausea/vomiting GI stasis (oral form is worse) Histamine release can cause systemic vasodilation

Answer 81

Mu and kappa agonist 50-100x the potency of morphine Indications Neuroleptanalgesia Induction Analgesia (provided frequent administration)

Answer 82

IV bolus CRI (preferred IV method) Slow release transdermal patch Epidural Duration of action 1-2 min onset; 10 min duration of action IV Usually CRI or slow release transdermal patch for analgesia

Answer 83

Defecation or constipation Resp depression Bradycardia Hypothermia Panting, drooling Dysphoria, agitation Sedation Not approved for food animals

Answer 84

Mu and kappa agonist Indications 5-10x the potency of morphine Moderate to severe pain (visceral and somatic) Pre, peri and postoperative pain control More sedation than morphine Rarely used in large animals because of lack of info about efficacy or adverse side effects

Answer 85

IV 1-2 hours IM 2-4 hours in dogs, longer in cats SQ up to 6-8h Epidural 8 hrs

Answer 86

Reliable emetic with first dose, especially if SQ/IM Diarrhea with first dose; constipation with chronic use Pant, drool Mydriasis in cats and horse Excitement /hallucinations in cats and horses

Answer 87

Resp depression Use with caution or contraindicated if severe resp disease Most common cause of fatality Bradycardia Hypothermia in all species Can cause occasional hyperthermia in cats which can be fatal In the event of a severe adverse reaction, can partially reverse with buprenorphine or butorphanol; can completely reverse with naloxone, naltrexone

Answer 88

Mu and kappa agonist Indications 5-10x the potency of morphine Moderate to severe pain (visceral and somatic) Low incidence of vomiting (compared to morphine or hydromorphone); other side effects similar to other pure mu agonists Excellent article summarising methadone released in the CVJ last year

Answer 89

Duration of action ~4hrs This is slightly longer than morphine and hydromorphone

Answer 90

Methadone is relatively new in canada Currently only licensed for use in cats; however, it is licensed for use in cats and dogs on other areas (Australia, New Zealand countries within the UN and EU) as an analgesic and preanesthetic agent Licensed in Canada: 0.5mg/kg IM in cats prior to spay or neuter. Extra-label: commonly used 0.2-0.5mg/kg administered IV, IM or SC

Answer 91

Mu and kappa agonist Indications 1/10x morphine Mild to moderate pain

Answer 92

Routes IM injection, NOT IV or SQ Histamine release with IV use Duration of action 30-90 min

Answer 93

No vomiting or bradycardia Use as premedication when no vomiting required

Answer 94

Super mu-agonist” 500-1000X the power of morphine But shorter acting than fentanyl

Answer 95

Intraoperative analgesia in dogs and cast as an infusion Induction

Answer 96

“Super mu-agonist” 10,000-100,000X the power of morphine

Answer 97

Wildlife capture and immobilization

Answer 98

Potentially fatal if handler scratches/injects self Use with extreme caution Wear double gloves when handling closed bottle

Answer 99

Requires naltrexone for reversal Draw up BEFORE handling carfentanil

Answer 100

Buprenorphine -Partial mu agonist, kappa antagonist

Answer 101

1/20x morphine Mild to moderate pain Less sedation Onset of action ~30 min

Answer 102

IV, IM, SQ, epidural or trans mucosal (in cats) Place in the buccal cavity or sublingual and allow absorption through the oral mucosa Will NOT work if swallowed Duration of action 6-8 hours in dogs and cats 2 hrs in sheep

Answer 103

Fewer side effects than hydromorphone due to partial mu-activity Slightly dysphoria

Answer 104

Higher affinity than naloxone, therefore requires much high doses or infusion of naloxone to reverse buprenorphine

Answer 105

Butrophanol/Turbugesic@

Answer 106

½ to 1x morphine Mild to moderate pain Analgesia and sedation are via the kappa-receptor Ex, colic Sedation Antitussive Reversal of hydromorphone SA (0.5mg/ml) and LA (10mg/ml) concentrations

Answer 107

IV, IM, SQ, PO

Answer 108

No mu-receptor mediated side effects Less resp depression No excitement No GI stasis No panting in dogs

Answer 109

Binds to and blocks mu-receptor Activation of kappa receptor produces mild to moderate analgesia and some sedation If butorphanol and hydromorphone are both present, butorphanol will bind to the receptor because it has 30X the affinity for the receptor compared to hydromorphone. Result is to kick out the hydromorphone and/or prevent the hydromorphone from binding to the receptor

Answer 110

Reversal of desirable and undesirable effects of opioid agonists, partial agonist, or agonist-antagonist including sedation and analgesia CNS and resp depression

Answer 111

IM, slow IV

Answer 112

Reversal of desirable and undesirable effects Sedation, dysphoria, panting, resp depression, hypotension, bradycardia, GI effects and analgesia The action of opioid antagonists if often dramatic, causing patient to appear nearly unaffected shortly after administration

Answer 113

Pure antagonist

Answer 114

Complete reversal of both mu and kappa agonists Will lose all adverse effects and all analgesia Dog, cat, horses, exotics, people 1 drop under tongue of neonates after C-section to reverse resp depression of opioid given to the mother

Answer 115

Duration of action 30-40 min; will need to top up Time of onset 2 min IV Aggressive use can cause catecholamine related cardiac arrhythmias and vasoconstriction leading to pulmonary edema

Answer 116

(pure antagonist) Both mu and kappa antagonist More potent than naloxone Used to reverse carfentanil in wild life Can be used intranasally Duration of action Long lasting (hours)

Answer 117

Kappa agonists, mu antagonist Only blocks mu activity; adds to kappa activity Not very strong reversal Leaves sedation and some analgesia Will reverse resp depression and hypo/hyperthermia

Answer 118

Naloxone * Naltrexone * Diprenorphine (M-50) is the reversal agent specifically created for etorphine (M-99)

Answer 119

Morphine Fentanyl Hydromorphone Methadone Meperidine/demerol Sufentanil Cerfentanil

Answer 120

Buprenorphine

Answer 121

Butorphanol/Turbugesic

Answer 122

Resp depression Bradycardia Miosis (mydriasis in cats) Hypothermia (hyperthermia in cats) Euphoria /dysphoria GI stasis (constipation) Urinary retention CRTZ (chemoreceptor trigger zone) for vomiting Antiemetic at the vomiting center

Answer 123

Miosis Mild sedation Little resp depression Diuresis

Preanesthetic medication Flashcards

(150 cards)