Pharmacology 2 - Exam 1

Flashcards covering neurotransmitters, anesthetic drugs, sedation, and neuromuscular blocking agents.

What are the three requirements for a substance to be considered a neurotransmitter?

1. Must be present in the presynaptic terminal

2. Must be released into the cleft when the presynaptic terminal depolarizes

3. Must have receptors on the postsynaptic membrane that it can activate.

Which compound is the most abundant excitatory neurotransmitter and does not cross the Blood-Brain Barrier (BBB)?

Glutamate.

What is the mechanism of action for Ketamine and Tiletamine regarding glutamate receptors?

NMDA receptor antagonists.

How do low versus high concentrations of Propofol and Etomidate affect GABA receptors?

Low concentrations enhance the action of GABA, while high concentrations directly activate GABA A receptors.

From what amino acid is Histamine synthesized?

Histidine.

Which neurotransmitter is synthesized from tryptophan?

5-HT (Serotonin).

What are the three categories of symptoms seen in Serotonin Syndrome?

Alterations in conscious state (agitation, anxiety, seizures), ANS dysfunction (hyperthermia, sweating, tachycardia, hypertension), and neuromuscular changes (hyperreflexia, ataxia).

The combination of which two drug classes typically leads to Serotonin Syndrome?

MAOI + SSRI.

What drug is used as a specific treatment for Serotonin Syndrome as a serotonin blocker?

Cyproheptadine.

What enzyme catalyzes the synthesis of Acetylcholine from choline and acetyl coenzyme A?

Choline acetyltransferase.

What is the mechanism of action for Ondansetron and Mirtazapine?

5-HT3 antagonist.

Why do antihistamines aid in motion sickness and causes drowsiness?

They cross the Blood-Brain Barrier and involve the vestibular apparatus and wakefulness pathways.

Why is morphine considered the most emetic producing opioid?

It is the least lipophilic opioid, meaning it has a hard time reaching the vomiting center to inhibit it, while it easily excites the CTZ.

What are the lipid solubility and ionization requirements for a drug to pass the Blood-Brain Barrier?

Drugs must be unionized, non-polar, and lipophilic (lipid soluble).

What ingredient in preservative-free drugs can increase intracranial pressure and be locally irritating?

Propylene glycol.

What is the primary justification for the use of anesthesia during surgery?

Prevention of noxious stimuli.

What is the difference between nociception and the perception of pain?

Nociception is the detection of painful stimuli with no emotional connotation; perception of pain occurs in the cerebral cortex.

What are the five components of General Anesthesia?

Reversibility, unconsciousness, amnesia, analgesia, and immobility.

What is 'Balanced Anesthesia'?

The use of multiple drugs at lower doses, where each drug is chosen for a specific purpose.

What is the primary mechanism of Propofol, Alfaxalone, and Etomidate at lower concentrations?

They enhance the effect of GABA.

Which drug was previously used for capital punishment and is no longer available?

Thiopental.

Where do inhalant anesthetics primarily produce immobility?

The ventral horn.

What is the #1 goal of the preanesthetic period?

Analgesia.

Which specific drug is a member of the Phenothiazine tranquilizer sedative class?

Acepromazine.

What drugs make up the BAM combination used in tranquilizer darts?

Butorphanol, Azaperone, and Medetomidine.

What is the specific reversal agent for Benzodiazepines like Diazepam and Midazolam?

Flumazenil.

Which barbiturate is used for chronic seizure management?

Phenobarbital.

Name the four drugs listed as full mu agonists (high intrinsic).

Morphine, Hydromorphone, Fentanyl, and Methadone.

What is the potency classification of Etorphine and its common nickname?

Ultra-potent opioid; "Elephant Juice" (M99).

What is the mechanism of action for Alpha-2 agonists?

They inhibit the release of norepinephrine, leading to reduced sympathetic tone.

What are the specific reversal agents for Xylazine and Dexmedetomidine?

Yohimbine (for Xylazine) and Atipamezole (for Dexmedetomidine).

Which species may experience 'Morphine Mania' due to CNS excitement?

Horses and Cats.

How is Butorphanol classified in terms of opioid receptor binding?

Agonist-antagonist (agonist at kappa receptors, antagonist at mu receptors).

What is the drug of choice (DOC) for 'windup' pain (inhibition of pain amplification in the dorsal horn)?

Ketamine.

What is 'catalepsy' in the context of dissociative anesthetics?

A state where the patient is cataleptic with autonomic reflex arcs (palpebral, laryngeal, corneal) remaining intact.

What is the composition of the drug combination known as 'Telazol'?

Tiletamine (dissociative) and Zolazepam (benzodiazepine).

What are the most common uses for Anticholinergic drugs like Atropine and Glycopyrrolate in anesthesia?

To counter bradycardia and produce bronchodilation.

Why are anticholinergics contraindicated in patients with G.I. stasis?

They reduce gut motility and gastric secretions.

How does Gentamicin interfere with the neuromuscular junction?

It blocks calcium channels at the motor nerve terminal, decreasing the release of Acetylcholine (Ach).

In what specific sequence are muscles typically affected by neuromuscular blocking agents?

Facial/head/neck/tail first —> limbs —> larynx —> abdominal/intercostal —> diaphragm.

Which neuromuscular blocking agent is a depolarizing agent available in veterinary medicine?

Succinylcholine.

What is the specific reversal agent for nondepolarizing neuromuscular blocking drugs?

Neostigmine.

What is the MAC (Minimum Alveolar Concentration) of Isoflurane in dogs and cats?

1.3% in dogs and 1.6% in cats.

What is the MAC of Sevoflurane in dogs and cats?

2.3% in dogs and 2.5% in cats.

What life-threatening myopathy involves a defect of the ryanodine receptor and is common in pigs?

Malignant Hyperthermia.

How does Nitrous Oxide use in horses affect the requirement for other inhaled agents?

It acts as an adjunct to sevoflurane to decrease the amount of other inhaled agents needed.

Why is recovery prolonged in thin patients like Greyhounds or Whippets after using lipid-soluble injectables?

They have small fat stores for the initial redistribution of the drug, making them more dependent on slower metabolism.

What schedule is Pentobarbital classified as when used as a short-acting euthanasia solution?

Schedule II

Which drug is added to Pentobarbital euthanasia solutions to increase cardiotoxicity and change the schedule to III?

Lidocaine.

What is the primary mechanism of action for Barbiturate anesthetics at the receptor level?

They increase GABA binding by decreasing the rate of dissociation of GABA from its receptor.

Why should thiobarbiturates not be used in Greyhounds?

They are deficient in the oxidative enzymes needed for metabolism.

What congenital condition in cattle makes the use of barbiturates dangerous due to increased porphyrin production?

"Pink tooth."

What are the common adverse effects of Propofol administration in cats?

Oxidative injuries to red blood cells (Heinz bodies), anorexia, and diarrhea.

What is 'Propofol Syndrome'?

A condition caused by prolonged continuous administration resulting in metabolic acidosis, kidney injury, arrhythmias, and cardiac failure.

Why is Propofol considered a good choice for endotracheal tube placement?

It decreases laryngeal reflexes.

What drug can be added to Propofol in horses to mitigate the excitement seen when used as a sole agent?

Guaifenesin.

What are the effects of Dissociative anesthetics on the cardiovascular system?

Increased sympathetic tone, tachycardia, and increased cardiac output due to inhibited catecholamine reuptake.

Describe the apneustic breathing pattern associated with Dissociative anesthetics.

A breathing pattern characterized by a long inspiratory pause followed by a short expiratory phase.

In which species does Tiletamine's duration of effect exceed that of Zolazepam in a Telazol dose?

Dogs.

What occurs when Zolazepam's duration exceeds Tiletamine's in cats during Telazol recovery?

Benzodiazepine tranquilization.

What is the 'Kitty Magic' drug combination?

Benzodiazepine + Ketamine + Opioid + Alpha-2 agonist.

Why is Etomidate often selected for patients with severe cardiovascular disease?

It has minimal effects on cardiovascular function and is not arrhythmogenic.

What is the mechanism of action for Alfaxalone?

Agonist at the GABA A receptor.

What is the chemical classification of Alfaxalone?

Synthetic neuroactive (nonhormonal) steroid.

What life-threatening adverse reaction is associated with the vehicle used in Alfaxalone?

Anaphylaxis due to histamine release.

Which fish anesthetic is FDA-approved for food-producing animals?

Tricaine methanesulfonate (MS-222).

What is the meaning of a 1% drug concentration in mg/mL?

10mg/mL (1g per 100mL).

What are the three components of the TKX combination used in pigs?

Telazol, Ketamine, and Xylazine.

What is the GKX protocol used in horses?

Guaifenesin, Ketamine, and Xylazine.

Why should Ketamine be avoided in patients with high sympathetic tone, such as those with hyperthyroidism?

It can increase norepinephrine levels and exacerbate symptoms.

What effect do Alpha-2 agonists have on urine production?

Increased urine volume due to inhibition of antidiuretic hormone (ADH) release.

Which anesthetic agent is preferred for sighthounds over barbiturates?

Propofol.

What is the primary disadvantage of using Ketamine as a sole agent in horses?

It causes dysphoria.