endocrinology Flashcards
types of inuslin
rapid acting - insulin aspart- Novorapid
short acting - soluble insulin - Actrapid
intermediate acting - isophane (NPH) - Humulin 1
Long acting - insulin glargine(lantus), insulin determir (levemir)
biphasic insulin preparations - mixture of rapid and intermediate - novomix 30 (aspart + aspart protamine)
mode of action of insulin
in diabetes, stimulates glucose uptake from circulation into tissues inc. skeletal muscle and fat and increases use of glucose as energy store
stimulates glycogen, lipid and protein synthesis and inhibits gluconeogenesis amnd ketogenesis
reduces serum K+ short term
indications for insulin
insulin replacement with type 1 diabetes and for blood flucose control in type 2 hwere oral hypoglycaemic treatment is inadequate
IV for diabetic emergencies (ketoacidosis, hyperglycaemias hyperosmolar synfrome and for perioperative glycaemic control)
hyperkalaemia - alongisde glucose while other measures initiated
contraindications for insulin
renal impairment
insulin clearance reduced = icnreased risk of hypoglycaemia
side effects of insulin
hypoglycaemia - severe can lead to coma and death
repeated SC injection at same site = fat overgrwoth (lipohypertrophy)
interactions of insulin
other hypoglycaemic agents increase risk of hypoglycaemia
concurrent therapy with systemic corticosteroids increase insulin requirements
gliclazide
sulphonylureas
gliclazide/sulphonylureas mode of action
lower blood glucose by stimulating pancreatic inuslin secretion
indications for sulphonylureas
type 2 DM
contorl blood glucose and reduce complications where metformin is contraindicated
in combo with metofrmin where blood glucose inadequately controlled
contra-indications of sulphonylureas
hepatic impairemnt - reduced dose
gluocse monitoring in renal impairment
side effects of sulphonylureas
dose related side effects such as GI upset
hypoglucaemia in high doses, or reduced drug metabolims or when in combo with other hypoglycaemics
hypersenstivity reactions are rare but cause hepatic toxicity, drug hypersensitivity syndrome and haematological abnromalities
interactions of sulphonylureas
increased risk of hypoglycaemia if prescribed with metformin, thiazolidinediones and insulin
efficacy reduced by drugs that elevate blood glucose - prenisolone, thiazide and loop diuretics
metformin
biguanides
mode of action of metformin/biguanides?
lowers blood glucose by increasing repsonse to insulin
does not stimulate pancreatic insulin so does not cuasse hypoglycaemia
reduces weight gain and induce wieght loss = prevent worsening of insulin resistance and deterioration of DM
indications of metformin/biguanides?
type 2 DM as first choice medication for control of blood glucose, used alone in combination with other hypoglycaemic drugs (sulphonylureas) or insulin
contraindications of metformin/biguanides
severe renal impairement
withheld in AKI, acute alcohol intoxication and chronic alcohol intoxication
caution in hepatic impairment
side effects of metformin/biguanides
GI upset
lactic acidosis - rare but fatal if untreated
interactions of metformin/biguanides
witheld 48hr post injection of IV contrast - increased risk of renal impairment, metformin acuclulation and lactic acidosis
other drugs impairing renal function
prednisolone thiazide, loop diuretics, elevate blood glucose and reduce efficacy
levothyroxine
thyroid hormone
levothyroxine mode of action
replaces thyroid hormones - liothyronine has shorter half life and quicker onset and offset so reserved for emergency treatment of severe or acute hypothtroidism
indications of levothyroxine
primary hypothyroidism
hypothyroidism secondary to hypopituitarism
contraindications of levothyroxine
precipitate cardiac ischaemia in those with CAD
corticosteroid therapy to avoid addisonian crisis in hypopituitarism
side effcts of levothyroxine
hyperthyroidism in excessive dosage - gastrointestinal (D+V, wt loss) , cardiac (palp, arrhyth., angina) and neurological (tremor, restlessness, insomnia) manifestations
possible interactions of levothyroxine
GI absorption reduced by antacids, caclium or iron salts (4hrs diff in admin)
increased dose in cytochromic P450 inducers
can increase insulin or oral hypoglycaemic requirements in DM and enhance warfarin
carbimazole
antithyroid
how does carbimazole work?
reduces production of thyroid hormones T3 and T4
indications for carbimazole
hyperthyroidism
contraindications fro carbimazole
early months of pregnancy
not ideally when breastfeeding
people with severe liver disease or blood disorders
side effects of carbimazole
rashes and pruritus are common - treat w antihistamines
bone marrow suppression is rare = neutropenia and agranulocytosis
possible interactions of carbimazole
warfarin
theophylline
erythromycin
steroids - prednisolone
alendronate
bisphosphonate
mode of action of bisphosphonate/alendronate
reduce bone turnover by inhibiting the action of osteoclasts (cell responsible for bone resporption)
= reduce bone loss and improve bone mass
indications for bisphosphate/alendronate
alendronic acid used as first line treatment for those at risk of osteoprootic fragility fractures
used as first line treatment of metabolically active pagets disease - reduce bone turnover and pain
contraindications of bisphosphonate
avoided in severe renal impairment
hypocalcaemia
oral contraindicated in upper GI disorders
risk of jaw osteonecrosis, avoid in somkers and major dental disease
side effects of bsiphosphonate
common side effect - oesophagitis and hypophosphatemia
osteonecrosis of jaw
atypical femoral fracture
interactions of bisphosphonates
bind calcium
absorption reduced if taken with calcium salts inc milk as well as antacids and iron salts
inidcations for caclium carbonate
osteoporosis
chronic kidney disease - prevent hyperparathyroidism and renal osteodystrophy
severe hyperkalaemia to prevent arrhythmias
severe hypocalcaemia
indications for vitamin D
osteoporosis
chronic kidney disease - prevent secondary hyperparathyroidism and renal osteodystrophy
prevent and treat vit D deficiency (rickets and osteomalacia)
contraindications of vit D and calcium
hypercalcaemia
side effects of calcium
oral calcium well tolerated but may cuase dyspepsia and constipation
Iv can cause cardiovacular collapse if too fast and tissue damage locally if given into SC tissue
interactions of calcium
reduces absorption of many drugs - iron, bisphosphonates, tetracycline and levothyroxine
IV should not mix with sodium bicarbonate due to risk of precipitation
fludrocortisone
mineralcorticoid
mode of action of fludrocortisone
mineralcorticoid replacement in adrenocortical insufficiency
indications of fludrocortisone
adrenocortical insufficiency
contraindications of fludrocortisone
systemic infection
avoid live virus vaccines
side effects of fludrocortisone
same as corticosteroids
interactions of fludrocortisone
increased risk of peptic ulcers and GI bleeds when used with NSAIDs and enhanced hypokalaemia in patients taking beta2agonists, theophylline, loop or thiazide diuretics
efficacy reduced by cytochrome P450 inducers
reduce immune response to vaccines
