TUTUR - Nervous System Drugs

Drugs that reduce the perception of pain

analgesics

Drugs that reduce or relieve anxiety

Tranquilizers

Drugs that make the patient sleepy

Sedation

Drugs that remove all sensations

anesthetics

Drugs that increase CNS activity

stimulants

Drugs that reduce seizure activity

anticonvulsants

What is the name for pain receptors?

nociceptors

What are the 4 steps of the pain pathway in order?

1. transduction

2. transmission

3. modulation

4. perception

What occurs during hyperalgesia?

inflammation process produces chemicals that increase firing of other nociceptors -making pain more intense

What is hyperesthesia?

increased sensitivity of non-pain receptors caused by inflammation

What is "wind up"?

increased spinal cord sensitivity over time due to repeated pain signals (greater perception of pain)

What do local anesthetics block?

All sensation at the nociceptor

What do anti-inflammatories reduce?

The number of pain impulses generated

What is the analgesic effect of epidurals?

They dampen pain signals in the spinal cord

What is the difference between opiates and opioids?

Opiates are from poppy extracts; opioids are synthetic "opium-like" drugs

What is narcosis?

A sleep-like state from which the patient is not easily aroused

What is a neuroleptanalgesic?

An opioid combined with a tranquilizer (e.g., butorphanol + diazepam)

What are the three opioid receptor types?

mu, kappa and delta

What is a full agonist?

A drug that produces maximal receptor effect

What is a partial agonist/antagonist?

Produces less effect and can partially reverse full agonists

What type of receptor produces the strongest analgesia?

mu receptor

What is a major GI side effect of opioids?

Constipation due to decreased GI motility and secretions

What cardiac effect do opioids cause?

Bradycardia

What is dysphoria?

Unpleasant hallucinations

What type of agonist is morphine?

Primarily mu agonist; some kappa activity

What type of pain is morphine best for?

Visceral pain and dull, aching pain

What causes vomiting with morphine?

Stimulation of the emetic center at low doses

What type of opioid agonists are hydromorphone and oxymorphone?

full mu agonists

How do hydromorphone and oxymorphone compare to morphine in potency?

They are more potent than morphine

Why are these drugs preferred over morphine in some cases?

They cause less vomiting than morphine, though vomiting can still occur

What is a unique possible side effect of hydromorphone in cats?

Hyperthermia

What type of opioid agonist is fentanyl?

Full mu agonist

What is fentanyl's duration when given as an injection?

short- about 30 minutes

Why are CRIs, patches, or transdermal solutions uesd for fentanyl?

For continuous analgesia

Can fentanyl patches be cut to adjust the dose?

NO

What is the typical duration of fentanyl patches in dogs?

about 2 days (1-3 range)

What type of opioid is butorphanol?

Mixed kappa agonist + mu antagonist.

Does butorphanol have a ceiling effect?

Yes, increaseing the dose does NOT increase analgesisa, only duration

What is its duration of action?

30-60 minutes in dogs, 90 minutes in cats

What is butorphanol commonly used for besides analgesia?

Antitussive (cough suppressant)

What receptor actions does buprenorphine have?

Strong kappa agonist, partial mu agonist

Does buprenorphine have a ceiling effect?

Yes, same as butorphanol

What is buprenorphine's major advantage over butorphanol?

uch longer duration (up to 8 hours)

Why is buprenorphine useful for cats?

It can be absorbed through the oral mucosa (transmucosal)

How long does Simbadol last in cats?

analgesia lasts at least 24 hours

Is tramadol a true opioid?

No, its metabolite is a mu agonist, but it acts through several mechanisms

Which species experiences the best analgesic effect from tramadol?

Cats

Why should tramadol NOT be combined with SSRIs or tricyclic antidepressants?

risk of serotonin syndrome

What is the primary opioid antagonist?

Naloxone

When would you use a partial antagonist instead of naloxone?

When you want partial reversal to maintain some analgesia

Which drugs act as partial agonist/antagonists?

Butorphanol and buprenorphine

Do sedatives and tranquilizers provide analgesia?

NO

What is acepromazine used for?

Sedation, calming, pre-anesthetic tranquilization

Does acepromazine have analgesia?

NO

How does acepromazine primarily work?

By blocking dopamine receptors in the brain

How does acepromazine affect vomiting?

It reduces vomiting by blocking dopamine receptors in the CRTZ

Why should acepromazine not be used in hypotensive animals?

t causes vasodilation by blocking alpha-1 receptors

Why should acepromazine not be used before allergy testing?

It blocks H1 histamine receptors, altering test results

What is the harmless eye effect associated with acepromazine?

Prolapse of the third eyelid (nictitating membrane)

What is the risk of using acepromazine in breeding stallions?

penile prolapse

Name the benzodiazepines

diazepam, midazolam, zolazepam and clonazepam

What is the mechanism of action of benzodiazepines?

Enhance the inhibitory neurotransmitter GABA --> CNS depression

Do benxos provide analgesia?

NO

Why are benzos good pre-anesthetic agents?

They counteract the CNS stimulant effects of dissociatives

What is the reversal for benzodiazepines?

Flumazenil

What are the common alpha-2 agonists used in vet med?

Xylazine, detomidine, medetomidine, dexmedetomidine, romifidine

Do alpha-2 agonists provide analgesia?

Yes

Does sedation or analgesia last longer with alpha-2s?

Sedation lasts longer

Do alpha-2 drugs have a ceiling effect?

Yes

What happens when alpha-2 receptors are stimulated?

Negative feedback stops norepinephrine release --> sedation & analgesia

Why do alpha-2 agonists cause vomiting, especially in cats?

Cats have many alpha receptors in the CRTZ

What cardiovascular changes occur initially?

Peripheral vasoconstriction leading to increased BP but severe bradycardia

What drugs reverse alpha-2 agonists?

Yohimbine and atipamezole

What is general anesthesia?

Reversible loss of sensation with unconsciousness

What is local anesthesia?

Loss of sensation in a specific area without unconsciousness

Does anesthesia equal analgesia?

No, anesthesia prevents perception of pain, but nociceptors can still fire

What drug has largely replaced barbiturates for anesthesia induction?

Propofol

What are the two barbiturates still used in vet med?

What are the two barbiturates still used in vet med?

What is pentobarbital used for?

Seizure control, limited anesthesia, euthanasia solutions

What is phenobarbital used for?

Long-term control of epilepsy (oral)

What is the duration of pentobarbital?

Short acting

What receptor does propofol stimulate?

GABA receptors

What receptor does propofol inhibit?

NMDA receptor

What is propofol primarily used for?

Induction of anesthesia; short procedures

Does propofol provide analgesia?

NO

How must propofol be administered?

Slow IV bolus or CRI

What happens if propofol is given too quickly IV?

Apnea

Why do animals rapidly recover from propofol?

Redistribution, drug leaves brain and returns to bloodstream quickly

What are the two primary dissociative anesthetics?

Ketamine and tiletamine (in Telazol)

What receptor do dissociatives block?

NMDA receptor

Do dissociatives provide analgesia?

Yes

Are dissociatives good alone for surgical pain?

No, insufficient for visceral or deep pain without opioids

What happens to heart rate and blood pressure with ketamine?

Both increase

Why must ketamine be used carefully in cardiac patients?

The increased HR and BP can be dangerous

: Are reflexes maintained during dissociative anesthesia?

Yes, pharyngeal, corneal, laryngeal reflexes remain

What effect do dissociatives have on muscle tone?

poor muscle relaxation (waxy rigidity)

What drugs reduce rigidity from dissociatives?

Benzodiazepines or alpha-2s

What must be done to protect the eyes during dissociative anesthesia?

Apply ophthalmic ointment since eyes remain open

Why may benzodiazepines be used during recovery?

To reduce dysphoric events

What is etomidate used for?

Induction of anesthesia, especially in patients with cardiac disease