Endocrine (year 2) Flashcards
what pharmacological agents are used to treat hyperthyroidism?
radioiodine and thioureylenes
what is the mechanism of action of radioiodine?
rapid selective uptake by thyroid and damaged cells, then emits short-range beta radiation that only effects thyroid follicle cell
how long after radioiodine will T3 and T4 levels begin to normalise?
1-2 weeks
how is radioiodine administered?
injection
what special precaution must be taken when giving a dog radioiodine?
hospitalised in isolation facilities for at least 2 weeks and excreta handled carefully
what species is radioiodine mainly used in?
cats
what is an adverse effect of radioiodine?
may cause hypothyroidism
name the thioureylenes
carbimazole and thiamazole
what is the mechanism of action of thioureylenes?
carbimazole is metabolised to methimazole which inhibits synthesis of thyroid hormones
how are thioureylenes administered?
orally once a day
what are the adverse effects of thioureylenes?
they are rare but may cause kidney problems in older cats
what drugs are used for hypothyroidism?
levothyroxine and liothyronine
what is the mechanism of action of levothyroxine and liothyronine?
they are identical to the endogenous version and given as replacement therapy
how are levothyroxine and liothyronine administered?
orally
what is the adverse effects of levothyroxine and liothyronine?
hyperthyroidism, tachycardia, excitability, nervousness
what agents can be used to treat adrenal disease?
glucocorticoid receptor agonist
mineralocorticoid receptor agonist
adrenal steroid synthesis inhibitors
dopamine receptor agonist
what is the mechanism of action of glucocorticoid receptor agonist?
enter cells by simple diffuse and synthetic glucocorticoids often aren’t protein bound
how are glucocorticoid receptor agonists administered?
topically, orally, systemically
what are the main uses of glucocorticoid receptor agonists?
replacement therapy for Addisons disease
anti-inflammatory
immunosuppressant
describe some adverse effects of glucocorticoid receptor agonists
Suppression infection/injury response Wound healing is impaired Cushing’s syndrome Osteoporosis Hyperglycaemia Muscle wasting Fluids/electrolyte imbalances Oedema Reduced milk yield s GI ulceration Abortion in late pregnancy Laminitis
how are mineralocorticoid receptor agonists administered?
inject
what are mineralocorticoid receptor agonists used for?
replacement therapy for dogs with Addisons disease
what are the adverse effects of mineralocorticoid receptor agonist?
they are rare but may cause polyuria or hypokalaemia
name a mineralocorticoid receptor antagonist
spironolactone - covered in diuretics
what is the mechanism of action of adrenal steroid synthesis inhibitors?
inhibits production of glucocorticoids, mineralocorticoid and sex hormones by inhibiting 3beta-hydroxysteroid-dehydrogenase
name an adrenal steroid synthesis inhibitors
Trilostane
how are adrenal steroid synthesis inhibitors administered?
orally
what are adrenal steroid synthesis inhibitors used for?
treat hyperadrenocorticism by suppressing glucocorticoid production
what are dopamine receptor agonists used for?
treat equine cushing
what is the route of administration of dopamine receptor agonists?
oral
name a dopamine receptor agonists
pergolide
what are two pharmacological agents used to effect calcium metabolism?
calcium salts and vitamin D preparations
what are calcium salts used for?
replacement therapy for dietary deficiency, hypocalcaemia, hyperphosphataemia
what calcium salt is used to treat hyperphosphataemia and how does it work?
calcium carbonate - an antacid that is poorly absorbed and binds to phosphate in the gut
give some examples of calcium salts used to effect calcium metabolism
calcium gluconate, calcium carbonate, calcium chloride, calcium borogluconate
how are calcium salts administered?
orally or parenterally (calcium gluconate)
what are some adverse affects of calcium salts?
cause GI upset, cardiac arrythmias
how are vitamin D preparations administered?
orally
what are vitamin D preparations used to treat?
hypocalcaemia following thyroidectomy or immune mediated hypoparathyroidism
what are the adverse effects of vitamin D preparations?
hypercalcaemia, hyperphosphataemia, nephrocalcinosis
what two drugs can be used yo treat diabetes mellitus?
insulin and oral hypoglycaemics
what are feline and canine insulin replacements made from?
canine - porcine
feline - bovine
what is the mechanism of action of insulin receptor agonists?
bind to insulin and have the same response as endogenous insulin
how are insulin replacements administered?
injected usually subcutaneously
oral preparations will be broken down by GI tract as they are peptides
what is insulin replacements used for?
treat type 1 diabetes
hyperglycaemic emergencies
emergency hyperkalaemia
what are the adverse effects of insulin receptor agonists?
hypoglycaemia
insulin resistance - antibodies or stress induced
insulin receptor desensitisation
name an oral hypoglycaemic drug
sulphonureas - glipizide
what is the mechanism of action of sulphonureas?
they stimulate insulin secretion from beta cells and increases insulin sensitivity - requires some normal beta cell function
what are sulphonureas used to treat?
type 2 diabetes in cats
what might be an adverse effect of the use of sulphonureas?
hypoglycaemia
