endocrinology Flashcards
insulin:
- 5 different length-acting? (incl examples)
- indications? 4
rapid acting
= immediate onset, short duration
- insulin aspart (eg novorapid)
short acting
= early onset, short duration
- soluble insulin (e.g. actrapid)
intermediate acting
= intermediate onset + duration
- isophane (NPH) insulin (eg humulin 1)
long acting
= flat profile with regular administration
- insulin glargine (lantus)
- insulin deter (levemir)
biphasic
= mixture of rapid + intermediate acting insulins
- e.g. novomix 30 (insulins aspart/insulin aspart protamine)
1) type 1 diabetes
2) type 2 diabetes (when oral treatment no longer effective/tolerated)
3) diabetic emergencies (e.g. ketoacidosis + hyperglycaemic hyperosmolar syndrome) + for preoperative glycemic control in diabetics
4) alongside glucose to treat hyperkalaemia (while treatment of underlying cause is being initiated)
insulin:
- mechanism of action?
- minor side effect?
- major adverse effect?
- stimulates glucose uptake from blood -> tissues
- stimulates glycogen, lipid + protein synthesis
- insulin drive K+ into cells (nb this is short term as, once stopped, K+ will leak out again)
- sub cut injections at same site -> lipohypertrophy (uncomfortable + unsightly)
- HYPOGLYCAEMIA (coma + death)
insulin:
- contraindication? (+ effect)
- relative interactions? 2
- renal impairment (insulin clearance is reduced -> higher change of hypo)
- other hypoglycaemic agents (increases risk of hypo)
- systemic corticosteroids (increases insulin requirements, so need more for same effect)
insulin:
- normal daily requirement of insulin (in units)?
- other lifestyle measures to regulate glucose levels better? 2
- initial symptoms of a hypo? 5
- ideal treatment of a hypo?
- monitoring? 2
about 30-50 units (though this varies)
- norm take one or two long-acting per day and then short or rapid injected with meals
- calorie-controlled diet
- regular exercise
- dizziness
- agitation (“hangry”)
- nausea
- sweating
- confusion
- something sugary then something starchy
- capillary glucose
- HbA1c (at least annually)
sulphonylureas:
- example?
- indication?
- mechanism of action?
- gliclazide
type 2 DM
- 2nd line, with metformin, if blood glucose not controlled
- 1st line, if metformin contraindicated or not tolerated
stimulate pancreatic insulin secretion
- by blocking ATP-dependent K+ channels in B-cell membranes -> depolarisation + opening of voltage-gated Ca2+ channels -> increased intracellular Ca2+ which stimulates insulin secretion
- sulphonylureas are only effective in patients with residual pancreas function
sulphonylureas:
- example?
- relative contraindications? 3
- gliclazide
- hepatic impairment
- renal impairment
- people at increased risk of hypos
nb people at increased risk of hypos
= hepatic impairment (reduced gluconeogenesis)
= malnutrition
= adrenal or pituitary insufficiency (lack of counter-regulatory hormones)
= elderly
sulphonylureas:
- example?
- mild side effects? 2
- serious adverse effects? 2
- gliclazide
- GI upset (nausea, vomiting, diarrhoea, constipation)
- weight gain (not great for long term)
- hypoglycaemia
- rare hypersensitivity reactions (hepatic toxicity, drug hypersensitivity reaction, haematological abnormalities)
sulphonylureas:
- example?
- interaction which increases hypo risk?
- interactions which reduce efficacy? 2
- gliclazide
- other anti-diabetic drugs (metformin, thiazolidinediones, insulin)
drugs which elevate blood glucose, e.g.:
- thiazide + loop diuretics
- prednisalone
sulphonylureas:
- when to take?
- other lifestyle measures to regulate glucose levels better? 2
- initial symptoms of a hypo? 5
- ideal treatment of a hypo?
- monitoring? 1
- take with food
- calorie-controlled diet
- regular exercise
- dizziness
- agitation (“hangry”)
- nausea
- sweating
- confusion
- something sugary then something starchy
- HbA1c (at least annually)
nb regular blood glucose only really needed if on insulin
nb test renal + hepatic treatment before commencing treatment
biguanides:
- example?
- indication?
- mechanisms of action? 3
- metformin (only one used tbh)
- type 2 diabetes (1st line)
- suppresses hepatic glucose production
- increases glucose uptake + utilisation by skeletal muscle
- suppresses intestinal glucose absorption
nb it is not fully understood how it does this
nb it does not stimulate pancreatic insulin secretion and so does not cause hypos (when used alone)
biguanides:
- example?
- minor side effects? 2
- serious adverse effect?
- metformin
- GI upset (nausea, vomitting, taste disturbance, anorexia, diarrhoea)
- weight loss (which can be good in long term)
lactic acidosis
- only occurs if other illness alongside use which….
- > metformin accumulation
(e. g. worsening renal impairment) - > increased lactate production (e.g. sepsis, hypoxia, cardiac failure)
- > reduced lactate metabolism (e.g. liver failure)
biguanides:
- example?
- relative contraindications? 4
- absolute contraindications? 3
- metformin
- moderate renal impairment
- hepatic impairment
- acute alcohol intoxication (may precipitate lactic acidosis)
- chronic alcohol overuse (risk of hypo)
+ severe renal impairment
+ AKI
+ severe tissue hypoxia (e.g. cardiac or rest failure or MI)
biguanides:
- example?
- groups of interactions? 3
- metformin
IV contrast media
- withheld before + for 48 hrs after injection
potential to impair renal function (-> accumulation + lactic acidosis)
- ACE inhibitors
- NSAIDs
- diuretics
nb can use above drugs but monitor renal function
drugs which elevate blood glucose, e.g.:
- prednisalone
- thiazide + loop diuretics
biguanides:
- when to take?
- other lifestyle measures to regulate glucose levels better? 2
- what symptoms to look out for? 5
- what to tell other doctors?
- wha to monitor? 2
- with food
- calorie-controlled diet
- regular exercise
lactic acidosis:
- vomiting
- stomach ache
- muscle cramps
- difficulty breathing
- severe tiredness
- if they are having an operation or x-ray, as metformin may need to be stopped before the procedure
- HbA1c (at least annually)
- renal function (before starting + at least annually)
nb regular blood glucose only really needed if on insulin
thyroid hormones:
- examples? 2 (+ what each actually is)
- indications? 2
- mechanism of action?
- levothyroxine (synthetic T4)
- liothyronine (synthetic T3)
1) primary hypothyroidism
2) hypothyroidism secondary to hypopituitarism
replace endogenous thyroid hormones
- nb T4 is converted to T3 (more active)
levothyroxine (T4) is almost always used
liothyronine (T3) has shorter half life + quicker onset
- reserved for emergency treatment of severe or acute hypothyroidism
