Endocrinology drugs Flashcards
How does insulin work?
Its a peptide hormone, lowers plasma glucose conc by stimulating glucose transport into fat and muscle, stimulates glycogen synthesis and inhibits gluconeogenesis
What is insulin’s relationship with potassium?
Causes potassium influx causing low plasma K+ conc, which is why it is used in emergency treatment of hyperkalaemia
What class of drug is gliclazide?
Sulfonylureas
How does gliclazide work?
Stimulates insulin production by binding to sulfonylurea receptors and blocking K+ channels in pancreatic B cells causing depolarisation and insulin release
What is required for gliclazide to work?
Residual B cell activity and therefore endogenous insulin
What class of drug is metformin?
Biguanides
How does metformin work?
Increases glucose utilization, decreases gluconeogenesis and GI glucose absorption
What indication do insulin, gliclazide and metformin have in common?
Type 2 Diabetes Mellitus
What is there an increased risk of when alcohol is used with metformin?
Lactic acidosis
Why is metformin the treatment of choice in obese patients?
It also decreases apetite
How does thyroxine work?
Mimics endogenous thyroxine, increases oxygen consumption of metabolically active tissues
What drug interactions does thyroxine have?
Increases warfarin effect, faster response to TCAs, faster metabolism of beta blockers
What drug is used in hyperthyroidism?
Carbimazole
How does carbimazole work?
Inhibits thyroid peroxidase which is responsible for thyroid hormone synthesis resulting in decreased production of T3 and T4.
When carbimazole is used for Graves’ disease, how long should treatment be continued for?
At least a year, when on carbimazole, regular monitoring is needed
What class of drug is alendronate?
Bisphophonates
How does alendronate work?
Inhibits osteoclast mediated bone resorption, need vitamin D and calcium to promote normal bone development
Indications for alendronate?
Osteoporosis
Contraindications for alendronate?
Abnormalities of the oesophagus and other factors delaying emptying, hypoglycaemia
How do antacids effect absorption of alendronate?
Decrease it
What important information should the patient be given when on alendronate?
Avoid taking other medicines or food for at least 30 mins after taking it to prevent altered absorption. Also need to sit/stand for 30 mins after taking it.
What drug class is fludrocortisone?
Mineralocorticosteroids
How does fludrocortisone work?
Binds mineralocorticosteroid (Aldosterone) receptor to increase ECF and blood pressure, retain Na+ and H2O and reduce K+ levels
Indications for fludrocortisone use?
Adrenocortical insufficiency/Addison’s disease
When can fludrocortisone not be used?
Systemic infections (particularly fungal)
What can develop if fludrocortisone is given in high doses?
Cushing’s syndrome
Why should reduction of fludrocortisone dose be gradual?
Too rapid a reduction can cause adrenal insufficiency, hypotension and death
