Endocrine Flashcards
Questions from endocrine chapter
How often should insulin-dependent diabetics check their blood glucose levels whilst driving?
2 hours before driving and every 2 hours whilst driving. A fast-acting carbohydrate snack should be available inside the cars and levels should be >5
‘Alcohol can mask hypos and cause delayed hypos’
True or false?
True
Diabetics should only drink with food + in moderation
How does metformin work?
- Decreases hepatic gluconeogenesis
- Increases peripheral glucose uptake
- Delays intestinal glucose absorption
Which oral antidiabetic drug is first line for all patients?
Metformin
‘Metformin is associated with weight gain’
True or False?
False - it has a positive effect on weight loss
Can metformin cause hypos?
No - causes normoglycaemia not hypoglycaemia. Does not stimulate insulin secretion so does not cause hypos
What is the most common side effect of metformin?
GI disturbances
What are risk factors for lactic acidosis in patients taking metformin?
- Heart failure
- Sepsis
- Renal failure (accumulation)
What are the monitoring requirements for metformin?
- Renal function before treatment and at least annually
- HbA1c
‘Lactic acidosis is rare when metformin is used as labelled but can occur in overdose’
True or false?
True
At what eGFR should metformin be avoided?
Less than 30ml/min
What is the maximum dose of metformin?
2g daily (SPC states 3g)
How would you manage a patient with an eGFR of 33ml/min who is on metformin?
Reduce dose to 25% and maximum 1 g per day
What is the renal dosing for metformin?
<30 ml/min - avoid
30-45ml/min - reduce to 25%, max 1g
45-59ml/min - reduce to 25-50%, max 2g
Why should metformin be stopped before surgery and when should it be restarted?
- General anaesthetic can cause ketoacidosis, suspend morning of surgery
- Restart when renal function returns to baseline
How would you manage a patient on metformin who requires an x-ray?
Iodinated contrast agents can cause renal failure and lactic acidosis.
Suspend metformin prior to x-ray and restart in 48 hours if renal function returns to baseline
Name some sulphonylureas?
Gliclazide, glibenclamide, glipizide, glimepiride, tolbutamide
How do sulphonylureas work?
Stimulate insulin secretion from beta cells in the islets of Langerhans. Only effective if some residual beta cell activity
‘Sulphonylureas can cause weight gain’
True or false?
True - should not be recommended to overweight/obese patients
Name a short-acting sulphonylurea
Gliclazide, tolbutamide
Name a long-acting sulphonylurea
Glibenclamide, chlorpropamide
Why are short acting sulphonylureas preferred to long acting ones?
Long acting sulphonylureas eg, glibenclamide are associated with severe prolonged/fatal episodes of hypoglycaemia
Should sulphonylureas be taken with food?
Yes
‘Gliclazide can commonly cause hypoglycaemia’
True or false
True- all sulphonylureas are associated with hypoglycaemia
Which class of antidiabetics are associated with blood disorders and agranulocytosis?
Sulphonylureas
Allergic skin reactions may occur in the fist 6-8 weeks of treatment with which antidiabetic class?
Sulphonylureas
‘Sulphonylureas are principally renally metabolised’
True or false?
False - they are metabolised in the liver mainly
Should be used with caution in renal impairment due to risk of hypos
Should be avoided in hepatic impairment and can cause hepatic disorders and choleostatic jaundice
Name 3 drugs that can interact with sulphonylureas?
- Chloramphenicol
- Miconazole / voriconazole
- Sulphonamides
‘Blood dyscrasias are a common side effect of sulphonylureas’
True or False
False- they are a rare side effect.
Why should gliclazide be used with caution in the elderly?
Sulphonylurea - risk of hypos
How does pioglitazone work?
Reduces peripheral insulin resistance
What are some common side effects of pioglitazone?
GI upset, weight gain, oedema, hypos, anaemia, visual disturbances, increased infection risk
Pioglitazone should be discontinued if signs of liver dysfunction occurs, what are some of the signs?
Dark urine, jaundice, fatigue, severe GI upset
What is the dose for Pioglitazone?
15-45mg per day taken with or without food
Can pioglitazone affect blood pressure?
It may lower blood pressure and improve lipid metabolism
What are the 2 MHRA warnings surrounding pioglitazone?
- Cardiovascular safety, risk of HF when used with insulin
2. Risk of bladder cancer
Pioglitazone should be monitored for signs of heart failure and it should be discontinued if there is deterioration in cardiac status, what are some signs of this?
Shortness of breath, oedema, fatigue, irregular heartbeat
What are some contra-indications for pioglitazone?
- Heart failure
- Previous/active bladder cancer
- Uninvestigated macroscopic haematuria
Why should pioglitazone be used with caution in the elderly?
Increased risk of heart failure and bladder cancer
‘Pioglitazone can increase risk of bone fractures’
True or false?
True, particularly in women
What can increase your risk of bladder cancer?
Smoking, age, previous exposure to agents such as radiation
How should pioglitazone be monitored?
Review efficacy after 3-6 months and stop if no response.
Monitor LFTs and cardiac status
Which symptoms should patients taking pioglitazone be counselled to report as they may be signs of bladder cancer?
Haematuria, dysuria or urinary urgency
‘Pioglitazone requires a dose adjustment in renal insufficiency’
True or false?
False -it is mainly hepatically cleared
Name some DPP-4 inhibitors?
Sitagliptin, saxagliptin, linagliptin, alogliptin, vildagliptin
How do DPP-4 inhibitors work?
Inhibits DPP-4 enzyme that breaks down incretins. Incretins trigger insulin secretion and reduce glucagon secretion
Which is the only DPP-4 inhibitor NOT licensed as monotherapy?
Alogliptin
The rest can all be used as monotherapy
‘Gliptins are more likely to cause hypos than sulphonylureas’
True or false?
False - gliptins can cause hypos but this has less incidence than with sulphonylureas
How would you manage a patient taking sitagliptin who presents with severe abdo pain and vomiting?
Potentially pancreatitis, discontinue treatment
Name some side effects of DPP-4 inhibitors?
Headache, GI upset, URTI, periperal oedema
Which is the only DPP-4 inhibitor that does NOT require a dose reduction in renal impairment?
Linagliptin - always 5mg OD
The rest should all be reduced
Can gliptins cause liver toxicity?
Yes- should be discontinued if symptoms of liver dysfunction occur
Dark urine, jaundice, fatigue, severe GI upset
Name some SGLT-2 inhibitors?
Canagliflozin, dapagliflozin, empagliflozin
How do SGLT-2 inhibitors work?
Inhibit sodium-glucose co-transporter 2 (SGLT2) in the renal proximal convoluted tubule to reduce glucose reabsorption and increase urinary glucose excretion
Why are UTIs common with SGLT2 use?
More glucose excreted in urine = more infections
Do SGLT2 inhibitors have to be taken with food?
No, taken once a day with or without food
What are some common side effects of SGLT2 inhibitors?
Constipation, thirst, polyuria, nausea, UTIs, hypos
Which class of anti-diabetics are associated with hypovolaemia?
SGLT2 inhibitors
Correct prior to treatment and look for signs such as dizziness or postural hypotension.
Risk higher in elderly, pts on anti-hypertensives, cardiovascular disease and GI illness
What MHRA warning is in place for all SGLT2 inhibitors?
Risk of diabetic ketoacidosis - potentiall life-threatening DKAs