Veterinary Pharmacology & Anesthesiology Review

Question-and-answer flashcards covering key facts on autonomic pharmacology, anesthetics, drug sources, adverse reactions, clinical uses, definitions, and physiologic effects as discussed in Sets A, B, and C of the lecture notes.

From which amino-acid is norepinephrine ultimately synthesized?

Phenylalanine (via tyrosine).

Acetylcholine is formed by the esterification of choline with what acid?

Acetic acid.

Which methyl-substituted analogue of acetylcholine is used as a diagnostic bronchial challenge agent?

Methacholine (β-methyl-acetylcholine).

Which class of animals is relatively resistant to belladonna (atropine) poisoning?

Herbivores.

What volatile anesthetic is considered the most nephrotoxic?

Methoxyflurane.

Which inhalant anesthetic is preferred for patients with asthma because of its strong bronchodilating effect?

Halothane.

What is the only inhalant anesthetic recommended for maintenance during ketamine anesthesia?

Halothane.

Which inhalant anesthetic does NOT precipitate malignant hyperthermia in swine?

Nitrous oxide.

What barbiturate is most commonly used in veterinary medicine for euthanasia and short anesthesia?

Pentobarbital (an oxybarbiturate).

Which ultra-short-acting barbiturate is preferred for induction in Greyhounds?

Methohexital.

Which animal class metabolizes pentobarbital more rapidly than others?

Herbivores (particularly ruminants).

In which species can propofol cause Heinz-body hemolysis with repeated use?

Cats.

Which intravenous anesthetic provides muscle relaxation and is routinely combined with ketamine and xylazine in horses ("triple drip")?

Guaifenesin (glyceryl guaiacolate).

What is the anesthetic of choice for fish?

Tricaine methanesulfonate (MS-222).

What inhalant anesthetic interferes with vitamin B12-dependent reactions and can cause megaloblastic anemia with prolonged exposure?

Nitrous oxide.

What is the historical name for urethane?

Ethyl carbamate.

What is the alternate (older) name for guaifenesin used in anesthesia texts?

Glyceryl guaiacolate.

What plant (scientific name) is the natural source of ephedrine?

Ephedra sinica (also E. equisetina).

From which plant (scientific name) is nicotine obtained?

Nicotiana tabacum (tobacco).

Arecoline is isolated from which plant?

Areca catechu (betel nut palm).

Tubocurarine is derived from which South-American vine?

Chondrodendron tomentosum.

Name the three components of the equine "triple drip" anesthetic.

Guaifenesin, ketamine, and xylazine.

Give three examples of ultra-short-acting barbiturates.

Thiopental, thiamylal, and methohexital.

List two commonly used dissociative anesthetics in veterinary practice.

Ketamine and tiletamine (often combined with zolazepam).

State two major clinical uses of α-adrenergic blockers in veterinary medicine.

Treatment of functional urethral obstruction (relax sphincter) and management of pheochromocytoma-induced hypertension.

Give three common therapeutic applications for β-adrenergic blockers in animals.

Control of supraventricular tachyarrhythmias, management of systemic hypertension, and treatment of feline hypertrophic cardiomyopathy.

Which part of the autonomic nervous system is embryologically equivalent to the sympathetic ganglia?

The adrenal medulla.

What cranial nerve constitutes the most important parasympathetic (cholinergic) trunk?

Vagus nerve (cranial nerve X).

Name an ultra-short-acting depolarizing muscle relaxant frequently used for intubation.

Succinylcholine.

Which CNS stimulant is contraindicated during halothane anesthesia because it precipitates arrhythmias?

Epinephrine.

Which anti-adrenergic drug blocks vesicular release of norepinephrine from nerve endings?

Bretylium (adrenergic neuron blocking agent).

Which drug acts as a "false transmitter," replacing norepinephrine in vesicles?

α-Methyldopa (L-methyldopa).

Define nociceptor.

A sensory receptor that transduces and transmits noxious (painful) stimuli.

Define hypnosis (as used in anesthesia).

A reversible state of artificially induced sleep or trance with loss of consciousness.

Define ataraxia.

A tranquil state in which the patient is calm and indifferent to its surroundings but remains responsive to external stimuli.

Define catalepsy.

A dissociative state characterized by muscular rigidity, fixed posture, and open eyes with nystagmus.

Define analgesia.

Absence or reduction of pain perception without loss of other sensory modalities.

Enumerate the four classical stages of general anesthesia.

Stage I – Analgesia; Stage II – Excitement (delirium); Stage III – Surgical anesthesia (planes 1-4); Stage IV – Medullary paralysis/overdose.

What is receptor "down-regulation"?

A decrease in the number and/or sensitivity of receptors on a target cell after prolonged exposure to an agonist, leading to diminished response.

Differentiate the two main classes of skeletal muscle relaxants used during anesthesia.

Depolarizing (e.g., succinylcholine) produce persistent depolarization and fasciculations; Non-depolarizing (e.g., d-tubocurarine, vecuronium) competitively block acetylcholine at nicotinic receptors without depolarizing the end-plate.

Why is external warmth provided during barbiturate anesthesia?

Barbiturates depress thermoregulatory centers and cause peripheral vasodilation, predisposing animals to hypothermia; external heat prevents dangerous drops in body temperature.

True or False: Succinylcholine is a non-depolarizing muscle relaxant.

False – succinylcholine is a depolarizing muscle relaxant.

True or False: Nitrous oxide is a vapor anesthetic.

False – nitrous oxide is a compressed gas anesthetic.

True or False: Guaifenesin produces effective skeletal muscle relaxation in horses.

True.

True or False: Morphine combined with atropine produces "twilight sleep" (neuroleptanalgesia).

True.

Stimulation of parasympathetic fibers to the iris causes .

Miosis (pupillary constriction).

Activation of α-receptors in systemic veins results in what effect?

Venoconstriction (increased venous return).

Activation of β-receptors in the uterus of most species produces what action?

Uterine relaxation (tocolysis).

Which three swine breeds are particularly susceptible to malignant hyperthermia?

Landrace, Pietrain, and Yorkshire (stress-susceptible lines).

Name two canine breeds with prolonged recovery or toxicity from thiobarbiturates.

Greyhounds and Salukis (lean sight-hounds).

List four antibiotics that can prolong or enhance barbiturate anesthesia by microsomal inhibition.

Chloramphenicol, erythromycin, tetracycline, and lincomycin.

Give three clinical indications for atropine use in veterinary medicine.

Pre-anesthetic to reduce salivation/bradycardia, treatment of organophosphate poisoning, and management of vagally mediated bradyarrhythmias.

State three therapeutic uses of cholinomimetic alkaloids (e.g., arecoline, pilocarpine).

Treatment of rumen atony, induction of miosis in glaucoma therapy, and expulsion of tapeworm segments (arecoline as a taeniacide in dogs).

Provide two examples of long-acting barbiturates.

Phenobarbital and mephobarbital.

Provide two examples of short-acting barbiturates.

Pentobarbital and secobarbital.

What dissociative anesthetic is notorious for causing apneustic breathing patterns in cats?

Ketamine.

Which puffer-fish toxin blocks voltage-gated Na⁺ channels and acts as a potent muscle relaxant?

Tetrodotoxin.

Which shell-fish poison causes paralytic shell-fish poisoning by Na⁺-channel blockade?

Saxitoxin.

Why are pre-anesthetic medications administered?

To calm the patient, reduce salivation and vagal reflexes, provide analgesia, decrease anesthetic dose requirements, and counteract anticipated adverse effects.

What are the recommended ambient temperatures for a surgical suite and a recovery room?

Surgery room: 18–22 °C (64–72 °F); Recovery room: 24–28 °C (75–82 °F) to counter postoperative hypothermia.