Pharmacology Midterm Review (Junior yr/Sem 1)

Which area is not protected by the blood-brain barrier and can directly detect emesis-producing compounds in the blood or cerebral spinal fluid (CSF)?

Chemoreceptor Trigger Zone (CRTZ)

Which of the following is an example of a "broad spectrum" phenothiazine tranquilizer used as an antiemetic?

Acepromazine

Dogs are particularly prone to vomiting from drugs that stimulate which type of receptors on the CRTZ or emetic center =?

Dopamine receptors

Maropitant (Cerenia) is a Neurokinin-1 antagonist that blocks the effect of Substance P in the nucleus tractus solitarius (NTS). This drug is approved for use in:

both dogs and cats

True or False: For inducing vomiting in cats, xylazine is often considered the injectable drug of choice because cats have more alpha receptors; therefore are more sensitive to it

True

Which of the following species is anatomically incapable of vomiting?

horses

Diarrhea resulting from damage to the GI tract wall, allowing large proteins, electrolytes, and blood to leak into the GI tract, is classified as?

exudative diarrhea

The "fight or flight" system, which reduces GI blood flow, motility, and secretions, is known as the:

sympathetic nervous system

True or False: Anticholinergic drugs are generally effective and recommended for treating diarrhea because they significantly slow GI motility and secretions without adverse side effects

False

Which of the following is not a function of the monogastric GI tract?

fermentation digestion

Which of the following medications is a cathartic commonly used in cats with megacolon, but also be used to reduce elevated ammonia levels

lactulose

Apomorphine primarily works as a centrally-acting emetic by stimulating:

dopamine receptors on the CRTZ

True or False: It is generally recommended to induce vomiting if an animal has ingested a corrosive substance like an acid or alkali

False

True or False: The emetic center, located in the brainstem, is protected by the blood-brain barrier

True

True or False: the parasympathetic nervous system primarily uses norepinephrine and epinephrine as its neurotransmitters to stimulate GI functions

False

This is the pump that maintains the polarization of ions on either side of the polarized cell membrane by actively pumping ions across the membrane

sodium potassium atpase pump

The period of time in which the cardiac cell cannot be stimulated to depolarize again regardless of the strength of the stimulus is the ___________________ refractory period

absolute

Stimulation of this receptor causes peripheral vasoconstriction

alpha

Stimulation of this receptor causes increased force of cardiac muscle contraction

beta

The condition of the atria or ventricles where the waves of depolarization are so disorganized that the heart quivers and does not contract in a coordinated manner

fibrillation

True or False: The depolarization/repolarization cycle or cardiac conducting cells differs from neurons because conducting cells have a plateau during the repolarization phase

True

True or False: At the polarized resting state, the concentration of sodium is higher on the outside of the cell than the inside

True

True or False: The AV node has slower automaticity than the SA node

True

True or False: An ectopic focus is damaged myocardial cell that fires on its own before the normal depolarization wave arrives

True

True or False: A drug that would block the action of acetylcholine would slow the heart rate

False

True or False: A slow heart rate caused by a poorly functioning SA node would be classified as a supraventricular bradycardia

True

True or False: an ACE inhibitor would block the formation of a vasodilator compound

True

True or False: The start of the Renin-Angiotensin-Aldosterone cascade is the release of renin from the kidney due to decreased blood flow

False

True or False: Aldosterone causes the kidney to reabsorb sodium from the urine in the renal tubules

True

True or False: Lidocaine is the drug of choice for treating arrhythmias originating from the SA node

False

AV block is a result of which system dominating?

parasymapthetic

Which of the following drugs is an inodilator that increases the binding of calcium to contractile elements and also causes vasodilation by inhibiting the enzyme phosphodiesterase (PDE)?

Pimobendan

What is the primary role of the renin-angiotensin-aldosterone system (RAAS) in response to decrease arterial blood pressure from heart failure?

To cause potent vasoconstriction via Angiotensin II and retain sodium and water via aldosterone

For which of the following conditions should ACE inhibitors, like enalapril, be used with caution or potentially avoided?

All of the above

If a veterinarian is seeing a patient's heart rate increase and arrhythmias reappear while on beta blockers, what is the likely cellular reason for this decreased drug effect?

the cardiac cells have produced more Beta 1 receptors on their surface in a process called upregulation

True or False: Centrally acting antitussives, such as opioids, should generally be avoided if the patient has a productive cough

True

Which part of the body, when stimulated, will NOT produce a cough?

Terminal bronchioles or alveoli

True or False: Histamine plays a significant role (similar to its role in humans) in causing bronchoconstriction in dogs

False

Which xanthine bronchodilator is primarily used in foals with respiratory distress syndrome, often given intravenously with oxygen therapy?

Aminophylline

Blocking Beta 2 receptors on the smooth muscle of the airways primarily allows the parasympathetic nervous system to dominate, resulting in:

Bronchoconstriction

When using a metered dose inhaler (MDI), the function of the "spacer" is to:

Allow the drug mist to mix with room air and inhaled with normal respiratory effort

What is the primary response elicited by the stimulation of the larynx, trachea, bronchi, and larger bronchioles?

coughing response

The mucociliary apparatus is structurally defined as:

a sheet of sticky mucus covering the ciliated epithelium

Epinephrine is classified as a mixed agonist that targets which receptors?

Alpha 1, Beta 1, and Beta 2

What is the typical initial injectable corticosteroid used in the emergency treatment of acute small airway disease (cat asthma)?

Dexamethasone

True or False: Furosemide is typically safe to use in animals with known kidney disease

True

True or False: Phenylephrine, an alpha 1 agonist, works as a decongestant by causing vasoconstriction, thereby decreasing capillary blood flow and mucosal edema in the bronchial tissue

True

Which of the following drug classes are considered the most effective for modification of airway resistance, regardless of the stimulus?

beta-adrenergic agonists and anticholinergic agents

What is the only species Clenbuterol is approved for use in treating asthma?

Horses

The primary mechanism by which corticosteroids (like Prednisone) act as anti-inflammatory drugs in the respiratory tract is by inhibiting which enzyme?

Phospholipase A2

What does heat do for an injury?

vasodilation (not actually increasing the temperature, just feels warmer) - brings blood supply to the injured tissues for repair

What is redness caused by inflammation?

blood vessels are closer to the skin giving it a reddish appearance

What does swelling do for an injury?

prevents movement of joints, reducing further injury

What does pain do for an injury?

prevents using the affected part

What does loss of function do for an injury?

prevents using the injured part

What is the goal of anti-inflammatories?

decrease pain associated with inflammation

What are eicosanoids?

substances that are produced when tissue is traumatized and create the signs of inflammation

What are examples of eicosanoids?

-prostaglandins

-leukotrienes

-thromboxanes

How do anti-inflammatory drugs work?

they reduce inflammation by blocking the formation of eicosanoids; decreased inflammation leads to fewer pain signals resulting in reduced perception of pain even though tissue is still traumatized

What are the two types of anti-inflammatory drugs?

-steroidal (glucocorticoid or corticosteroid drugs)

-non-steroidal (NSAIDs)

What are nociceptors?

pain receptors

What do corticosteroids inhibit in order to prevent pain from inflammation?

phospholipase A2

What do NSAIDs inhibit in order to prevent pain from inflammation?

Cyclooxygenase (COX) and Lipoxygenase (LOX)

What are adrenocorticosteroids?

hormones produced by the cortex of the adrenal

What do mineralocoticoids do?

-regulate electrolytes and water balance

-have no anti-inflammatory effect

-aldosterone is the natural mineralocorticoid-- causes the kidney to reabsorb sodium from the urine back into the body

What do glucocorticoids do?

-participate in homeostasis

-maintain supply of blood glucose

-maintain microcirculation, normal vascular

-permeability and stability of lysosomal membranes

-suppress inflammatory reactions

Desoxycorticosterone

-mineralocorticoid

-the only mineralocorticoid used in vet med

-primary use is to treat the clinical signs of hypoadrenocorticism (low functioning adrenal cortex) also known as Addison's disease

-mimics aldosterone effect by increasing reabsorption of sodium from urine and retaining it in the body

What is cortisol?

the natural glucocorticoid released by the adrenal cortex

What is CRF? What does it do?

-Corticotropin-Releasing Factor

-stimulates pituitary to release ACTH

What is CRH? What does it do?

-Corticotropin-Releasing Hormone

-stimulates pituitary to release ACTH

What is ACTH? What does it do?

-Adrenocorticotropic Hormone

-stimulates adrenal gland cortisol production

What are exogenous glucocorticoids?

exogenous glucocorticoids = glucocorticoid drugs; have the same negative feedback suppression on CRF and ACTH that natural cortisol does -> this decreases adrenal activity and cortisol

Hydrocortisone

-glucocorticoid

-short acting (

What are the types of immediate acting glucocorticoid drugs we learned?

-prednisone

-prednisolone

-methylprednisolone

-triamcinolone

What is the difference between prednisone and prednisolone?

-prednisone must be converted by the liver to prednisolone for its maximal effect

-these drugs are essentially the same in the dog

-conversion of prednisone to prednisolone is less efficient in the cat because of their metabolism, so cat dose of prednisone is higher than cat dose of prednisolone to achieve the same anti-inflammatory effect

What are the long acting glucocorticoids we learned?

-dexamethasone

-betamethasone

-flumethasone

The "methasones": dexamethasone, betamethasone, and flumethasone

-long acting glucocorticoid (>48 hr effect)

-longer acting but longer suppression of hypothalamus and pituitary with adrenal suppression

-greater risk for side effects related to 48+ hour continuous effects on many systems in the body

Aqueous solution

-drug dissolved in water

- drug name + "sodium" "phosphate" added

-can be given safely IV high doses

Alcohol solution

-drug dissolved in alcohol

-drug name without additional compound listed

-given IV but not as high a dose as aqueous solutions

Suspensions

-drug floating in liquid but not dissolved in it

-drug name + acetate, pivalate, acetonide, or valerate

-never give IV

Physiological dosage of glucocorticoids

dose that replaces amount of natural endogenous cortisol in a 24 hour period

Anti-inflammatory dosage of glucocorticoid

dose that is used to control allergies, hives, injury inflammation

Immunosuppressive dosage of glucocorticoid

dose that is used to suppress the immune system and to treat autoimmune diseases like immune mediated hemolytic anemia, pemphigus

Shock dosage of glucocorticoid

very high doses--generally not recommended any more for treatment of shock, spinal trauma, etc

What are supraphysiological dosages of glucocorticoids?

they introduce far greater levels and effects of glucocorticoids than could be achieved with natural production of cortisol

How does the anti-inflammatory effect of glucocorticoids work?

-inhibition of phospholipase A2

-decreases formation of prostaglandins, leukotrienes and maintains capillary integrity

-decreased fibroblast activity at anti-inflammatory and dosages - fibroblasts produce strong collagen fibers

How does the decreased immune response effect of glucocorticoids work?

-anti-inflammatory dosages will suppress activation of T-lymphocytes and its cell mediated immunity which is the major defense against bacteria and fungi causing risk for fungal infections

-B lymphocyte response is far less than T cell

How do glucocorticoids produce a shift in cells seen on the CBC?

-called the glucocorticoid stress response

-they cause lymphocytes and eosinophils to become sequestered by tissues -> fewer of these cells remain in systemic circulation to be samples (lymphopenia + eosinopenia)

-they cause neutrophils "parked" along the blood vessel walls to come off the walls and re-enter circulation (neutrophilia)

What are the classic NSAIDs we learned?

-Aspirin

-Flunixin meglumine

-Phenylbutazone

What are the selective COX 2 Inhibitors (COXIBs) we learned?

-Carprofen

-Etodolac

-Meloxicam

-Deracoxib

-Firocoxib

-Robenacoxib

What does it mean if a drug is highly protein bound?

they have many of their molecules "stuck" on protein in the blood

What happens if an animal with hypoproteinemia is given highly protein bound NSAIDs?

doses of highly protein bound NSAIDs may need to be decreased under hypoproteinemia conditions to prevent toxic concentrations from reaching tissues

What is the most frequent side effect of NSAIDs?

GI irritation due to COX 1 inhibition

What is NSAID induced renal papillary necrosis?

-NSAIDs will block renal vasodilating COX

-low blood pressure + NSAID = marked decrease blood flow to the kidney (some parts of the kidney will be deprived of adequate oxygen)

Aspirin

-classic NSAID that is safe for dogs and cats

-primary use is for chronic joint inflammation

What is the half life of elimination for salicylates in mammals?

man: 1.5 hours

ruminant: 1 hour

horse: 5 hours

dog: 8 hours

cat: 1-1.5 days

Flunixin meglumine (Banamine)

-used in horses and cattle for laminitis and colic

-stronger analgesia effect than aspirin

Phenylbutazone (Bute)

-nonselective NSAID used for equine lameness and musculoskeletal inflammation

-highly protein bound

-dont use in dogs- causes hepatotoxic effect and aplastic anemia

-IV and PO only

Carprofen (Rimadyl)

-COX 2 selective NSAID

-first selective COX 2 inhibitor approved for dogs only

-does not inhibit thromboxane like aspirin

Etodolac

-COX 2 selective NSAID

-used for dogs to treat osteoarthritis