Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology - VAP844 > Corticosteroids and Endocrine Therapy > Flashcards

Corticosteroids and Endocrine Therapy Flashcards

1
Q

Adrenocorticosteroids

A
  • Adrenal Cortex:
    1. Glucocorticoids
      1. effect on intermediary metabolism (Cortisol)
    2. Mineralicorticoids
      1. reabsorption of sodium and water
      2. Elimination of potassium (Aldosterone)
    3. Sex steroids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hypothalamic-Pituitary-Adrenal Axis

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Glucocorticoids:

Mechanism of Action

A
  • Alter protein expression
    • bind to intercellular receptors
    • Translocated to the nucleus
    • Bind to receptors on Glucocorticoid Response Element
    • Effect RNA transcription and subsequent protein synthesis / expression
  • Inhibition of nuclear factor Kappa-B (NF-kB)
    • NF-kB is primarily a pro-inflammatory nuclear transcription factor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Glucocorticoids:

Cellular Effects

A
  • PMN, Macrophages
    • Decrease ability to engulf cells and process antigens
      • immunosuppresive dosages
    • Decrease adhesion, migration
      • anti-inflammatory dosages
      • Incease in mature circulating PMNs due to release from the marginal pool and decreased tissue migration
  • Lymphocytes
    • T cell suppression Primary effect
    • B cell antibody synthesis minimally affected at anti-inflammatory doses
    • Lympholytic - higher doses
  • Eosinophils / Basophils
    • decreased migration and numbers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Glucocorticoids:

Cellular Effects:

Cytokine Inhibition

A

IL-1, IL-2, IL-6, TNF-a, histamine, bradykinin, serotonin, platelet activating factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Glucocorticoids:

Cellular Effects:

Arachidonic Acid Pathway

A
  • Inhibits phospholipase A2
    • Prostaglandins
    • Leukotrienes
    • Prostacyclin
  • Some inhibition of COX-2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Glucocortcoids:

Metabolic Effects:

Stimulate Gluconeogensis

A

Increase serum glucose

increase serum insulin

Decrease cellular uptake of glucose

Stimulation of lipogenesis and increased fat deposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Glucocorticoids:

Metabolic Effects:

Catabolic and Antianabolic Effects

A

Decreased muscle mass and thinning

Decreased skin thickness

Osteoporosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Glucocorticoids:

Other Effects

A
  • Euphoria
  • Feeling of well being
  • Maturation of fetal lungs
  • Low doses decrease CSF production
  • High doses increase intracranial pressure
  • Inhibition of arginine vasopression (ADH) release
  • Phychogenic polydipsia
  • Mineralocorticoid Effects:
    • drug dependent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glucocorticoid Usage

A
  • Physiologic replacement
    • prednisone
    • Hydrocortisone
  • Anti-inflammatory
    • prednisone
  • Immunosuppressive
    • prednisone
  • Shock Dose
    • Methylprednisolone sodium succinate
    • Only Solu-medrol for spinal trauma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Glucocorticoids:

Clinical Use:

Short Term Therapy

A

Administrated daily at anti-inflammatory doses without serious long-term adrenal adverse effects

Abrupt discontinuation can be performed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Glucocorticoids:

Clinical Uses

Long-term Therapy:

A

Titrate to lowest effective dose

Typically administered every other day

Recovery of adrenal function within 14 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Corticosteroid Metabolism

A

Primarily hepatic metabolism

Minimal secreted in urine as unchanged drug

The pharmacologic effects persist beyond plasma concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Choice of Corticosteroid:

Dogs

A
  • Prednisone
    • Pro-drug that is metabolized to prednisolone
  • Prednisolone
    • intermediate acting and administered EOD
  • Dexamethasone - less common
    • Longer duration, 2-3X per week
  • Depo Medrol
    • long acting repository formulation
    • Not recommended systemically for dogs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Choice of Corticosteroid:

Cats

A
  • Prednisolone is the corticosteroid of choice
  • Intermediate acting and administered EOD
  • Often require higher dosages than dogs to elicit similar effects
  • More resistant to adverse effects
  • Repository forms (Depo-Medrol) can be used in cats, but have increased adverse effects inc ats compared to prednisolone
  • Dexamethasone is a reasonable alternative in cats
    • 2-3X per week
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Choice of Corticosteroids:

Horses

A
  • Prednisone poorly absorbed and poorly converted
  • Dexamethasone
    • drug of choice
  • Prednisolone
    • OK, but costs more
17
Q

Choice of Corticosteroid:

Cattle

A
  • Dexamethasone
    • drug of choice
  • Low dose - no withdrawal time
  • High dose - withdrawal time
18
Q

Formulations:

Phosphate and Succinate Esters

A

Highly water soluble rapid onset

Methylprednisolone sodium succinate

Dexamethasone sodium phosphate

19
Q

Formulations:

Solutions

A

Dexamethasone solution

20
Q

Formulations:

Acetate and Acetonide ester suspensions

A

Poorly water soluble, prolonged absorption and effect

Methylprednisolone acetate

21
Q

Glucocorticoids:

Adverse Effects

A
  • PU/PD
  • Polyphagia
  • Increased ALP
  • Hyperglycemia
    • insulin resistance
  • Secondary Infections
    • Urinary tract infections
    • Demodex
    • Toxoplasmosis
    • Fungal
  • GI adverse effects
    • Vomiting
    • Diarrhea
    • GI ulceration / perforation
  • Atrophic Dermatopathy
  • iatrogenic Cushing’s dz
  • Steroid Hepatopathy
  • Proteinuria, glomerular pathology
  • Abortion (high doses / late gestation)
  • Decrease bone / wound healing
  • Adrenal atrophy
  • Na+ / water retention (Mineralocorticoids)
  • Peripheral Edema
  • Hypertension
  • Pancreatitis
  • Behavioral Changes
  • Cataracts
  • Glaucoma
  • Laminitis
22
Q

Glucocorticoids:

Contraindications and Precautions

A
  • Infectious disease
  • Diabetes mellitus
  • Liver disease
  • Protein losing nephropathy
  • Protein losing nephropathy
  • Pregnancy
  • Delayed wound / fracture healing
  • Glaucoma
  • Corneal Ulcer
  • GIT ulceration / injury
23
Q

Glucocorticoids:

Drug Interactions

A
  • NSAIDs:
    • increased risk of GI ulceration
  • Insulin:
    • Decreased efficacy of insulin
  • Phenobarbital:
    • Increased metabolism of corticosteroids
  • Hypokalemia results in increased adverse effects of:
    • Furosemide - hypokalemia
    • Digoxin - Increased risk of toxicity dur to hypokalemia
24
Q

Hypoadrenocorticism:

“Addison’s disease”

A
  • Typically deficiency of glucocorticoids and mineralicorticoids
  • Result:
    • sodium loss
    • Potassium retention
      • arrhythmias, bradycardia, heart block
    • Hypovolemia
  • Supplement of mineralocorticoid and glucocorticoid
    • fludrocortisone or desoxycorticosterone and prednisone or hydrocortisone
25
Q

Hyperadrenocorticism:

Excessive production of cortisol:

In Dogs

A
  • Pituitary adenoma resulting in excessive ACTH and subsequently excessive cortisol
  • Or by a functional adrenal tumor
26
Q

Hyperadernocirticism:

Excessive production of Cortisol

In horses

A
  • Loss of dopaminergic inhibition of the pars pituitary intermedia resulting in increased release of proopiomelanocortin (ACTH Precursor) and subsequently increased release of ACTH and cortisol
27
Q

Trilostane:

Mechanism of Action

A
  • REVERSIBLE inhibition of B-hydroxysteroid dehydrogenase in the adrenal cortex primarily resulting in inhibition of glucocorticoid synthesis
  • Mineralocorticoid synthesis is affected to a lesser extent
  • Hepatic Metabolism
  • Primarily used in dogs, rarely in horses
28
Q

Trilostane:

Adverse Effects

A
  • Vomiting, Nausea, Diarrhea, Lethargy
  • Acute death rarely repoted
  • Adrenal cortex necrosis - rare
29
Q

Mitotane:

Mechanism of Action

A
  • Cytotoxic effects of zona fasiculata and reticularis
30
Q

Mitotane:

Pharmacokinetics

A

Oral absorption enhanced with food

31
Q

Mitotane:

Adverse Effects

A
  • Nausea, anorexia, vomiting
  • Mild hypoglycemia
  • CNS depression
  • Hepatotoxicity
  • Weakness, diarrhea, lethargy
  • Destruction of Zona Glomerulosa resulting in addison’s disease
32
Q

Pergolide:

Mechanism of Action

A
  • Dopamine receptor agonist
  • Suppresses ACTH release from pituitary
  • Approved for use in horses
33
Q

Pergolide:

Adverse Effects

A
  • Inhibits release of prolactin
  • Ataxia, Dyskinesia
  • Anorexia, diarrhea, Colic
34
Q

Feline Hyperthyroidism

A
  • Most commonly functional thyroid adenoma
  • Results in excessive secretion of thyroid hormone
  • Weight loss:
    • increased appetite, thirst and urination, Vomiting, diarrhea, hyperactivity, unkept hair coat, tachycardia, hypertension
  • Treatment options:
    • methimazole, I-131, surgery diet
35
Q

Methimazole:

Mechanism of Action

A
  • Competitive inhibitor of thyroid peroxidase
    • decreases formation of T4, and T3
    • Does not affect preformed thyroid hormone
    • Does not inhibit conversion of T4 → T3
36
Q

Methimazole:

Pharmicokenetics

A
  • Oral, transdermal
  • Good PO bioavailability
  • Half-life ~ 3-4 hours
  • Adjust dose based on T4 monitoring
37
Q

Methimazole:

Adverse Effects

A
  • Vomiting, anorexia most common
  • Polyarthritis, alopecia, and scaling of head/face, anemia, thrombocytopenia
  • Rare:
    • vasculitis, bone marrow suppression
  • Treatment may unmask renal dysfunction
38
Q

I-131 Radioactive Iodine

A
  • Use requires a radioisotope permit
  • Singel SQ injection effective in more than 95% cases
  • Rapidly absorbed and transported to thyroid gland
  • Concentration in the adenoma resulting in selective toxicity
  • Cats hospitalized in isolation for 3-5 days or until urine radioactivity drops to acceptable level
  • Cats require restricted activity for 3 weeks as radioactivity in urine decreases
  • Well tolerated, some cats have increased swallowing after initial treatment

Pharmacology - VAP844 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions