Endocrinology Drugs Flashcards

1
Q

Insulin examples

A

Insulin aspart, insulin glargine, biphasic insulin, soluble insulin

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2
Q

Insulin indications

A
  1. Insulin replacement in TI DM
  2. Control of blood glucose in TII DM where oral hypoglycaemics inadequate / poorly tolerated
  3. IV in diabetic emergencies e.g. DKA, hyperglycaemic hyperosmolar syndrome
  4. Hyperkalaemia: alongside glucose while underlying cause investigated
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3
Q

Insulin MOA

A

Comes in rapid, short, intermediate, long acting and biphasic forms.

DM: works in similar way to endogenous insulin.

  • Increases glucose uptake
  • Increases use of glucose as energy
  • Stimulates glycogen, lipid and protein synthesis
  • Inhibits gluconeogenesis and ketogenesis

Hyperkalaemia: drives K+ into cells. Only short-term as leaks out again once stopped.

NB: biphasic insulin contains mixture of rapid and intermediate acting. Number in name indicates % short-acting

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4
Q

Insulin administration

A

SC: self-administered

IV in diabetic emergencies

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5
Q

Insulin contrainidactions

A

Higher risk of hypoglycaemia in renal failure as clearance reduced

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6
Q

Insulin side effects

A

Hypoglycaemia: coma and death

Lipid overgrowth at SC injection site

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7
Q

Insulin interactions

A
  1. Hypoglycaemic agents: increased risk hypoglycaemia

2. Corticosteroids: increases requirements

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8
Q

Gliclazide class

A

Sulphonylureas

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9
Q

Gliclazide indications

A
  1. TII DM: single agent to control blood glucose and reduce complications where metformin contraindicated or not tolerated
  2. TII DM in combination with metformin where glucose not adequately controlled
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10
Q

Gliclazide MOA

A
  • Stimulates pancreatic insulin secretion
  • Block ATP dependent K+ channels in beta-cell membranes
  • Causes depolarisation of cell and opening of voltage gated Ca2+
  • Increases intracellular Ca2+
  • Stimulates insulin secretion
  • Only useful in pts with residual pancreatic function.
  • Insulin anabolic hormone - causes weight gain
  • Weight gain increases insulin resistance, can worsen DM in long term
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11
Q

Gliclazide contraindications

A
  • Hepatic / renal impairment: dose reduction

- Caution in those at risk of hypoglycaemia

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12
Q

Gliclazide side effects

A

Dose-related: Infrequent but include nausea, vomiting, diarrhoea and constipation.

Hypoglycaemia: caution in high doses / combination.

Hypersensitivity: rare but include hepatic toxicity, drug hypersensitivity syndrome, haematological abnormalities

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13
Q

Gliclazide interactions

A
  • Other hypoglycaemic agents

- Efficacy reduced by drugs which elevate glucose: prednisolone, thiazide / loop diuretics

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14
Q

Gliclazide patient info

A

Take with meals

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15
Q

Metformin class

A

biguanides

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16
Q

Metformin MOA

A
  • Lowers blood glucose by increasing sensitivity to insulin.
  • Suppresses hepatic glucose production .- glycogenolysis and gluconeogenesis
  • Increases glucose uptake and utilisation by skeletal muscle and suppresses intestinal glucose absorption
  • Does not stimulate pancreatic insulin secretion and therefore does not cause hypoglycaemia
  • Reduces weight gain and can induce weight loss - prevents worsening of insulin resistance
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17
Q

Metformin indications

A

TII DM: 1st line for controlling blood glucose. Alone or combination.

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18
Q

Metformin contraindications

A
  1. Severe renal impairment as excreted unchanged - dose reduce if moderate
  2. AKI / severe tissue hypoxia: withhold acutely
  3. Hepatic impairment: impaired clearance of excess lactcate
  4. Alcohol: acute intoxication - withhold as precipitates lactic acidosis. Chronic use risk of hypoglycaemia, use with caution.
19
Q

Metformin side effects

A
  • GI upset
  • Lactic acidosis: rare but fatal - caused by: concurrent illness that causes metformin to accumulate (renal disease), increased lactate production (sepsis, hypoxia, cardiac failure) reduced lactate metabolism (liver failure)
20
Q

Metformin interactions

A
  1. Contrast: withhold 48 hours before and after due to risk of metformin accumulation, renal impairment and lactic acidosis.
  2. Other drugs that risk renal impairment: ACEi, NSAIDs, diuretics - monitor renal function
  3. Drugs which elevate glucose: prednisolone, thiazide and loop diuretics: - reduce efficacy
21
Q

Metformin patient information

A

Swallow with whole glass of water, with / after food. Aware of signs of lactic acidosis. Advise lifestyle being more permanent treatment.

22
Q

Thyroxine examples

A

Levothyroxine, leiothyronine

23
Q

Thyroxine indication

A

Primary or secondary hypothyroidism

24
Q

Thyroxine MOA

A
  • Thyroid produces T4 which is converted to more active T3 in target tissue
  • Levothyroxine = synthetic T4.
  • Liothyronine = synthetic T3 - shorter half-life, rapid action - reserved for emergency treatment of severe hypothyroid
25
Q

Thyroxine contraindications

A
  • Increase HR and metabolism: can precipitate ischaemia in coronary artery disease
  • Hypopituitarism: corticosteroid therapy must be initiated before to avoid Addisonian crisis
26
Q

Thyroxine side effects

A

Due to excessive doses, similar hyperthyroidism

27
Q

Thyroxine interactions

A
  1. Antacids / calcium / iron salts: absorption reduced, so must separate by ~4h
  2. cP450 inducers: reduce efficacy
  3. Insulin: metabolism changes can increase insulin requirements
  4. Warfarin: metabolism can enhance effects
28
Q

Carbimazole class

A

Imidazole anti-thyroid agent

29
Q

Carbimazole indications

A
  1. Hyperthyroidism and thyrotoxicosis

2. Prepare patients for thyroidectomy

30
Q

Carbimazole MOA

A
  • Decreases uptake and concentration of inorganic iodine by thyroid
  • Reduces formation of diiodotyrosine and thyroxine.
  • Once converted to its active form, it prevents thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, which reduces production of T3 or T4.
31
Q

Carbimazole contraindications

A
  1. Blood disorders
  2. Hepatic impairment
  3. Pregnancy / lactation
32
Q

Carbimazole side effects

A

Common: arthralgia, fever, malaise, mild GI disturbance

Rare: agranulocytosis, alopecia, bone marrow suppression, jaundice, myopathy, pancytopenia

33
Q

Carbimazole interactions

A

Warfarin: increases anti-coagulant effects

34
Q

Bisphosphonates examples

A

Alendronic acid, disodium pamidronate, zoledronic acid

35
Q

Bisphosphonates indications

A
  1. Alendronic acid: 1st line for patients at risk of osteoporotic fragility fractures
  2. Pamidronate and zoledronic acid: severe hypercalcaemia of malignancy after appropriate IV rehydration
  3. Myeloma and breast cancer with bone metastases: pamidronate and zoledronic acid reduce risk of pathological fractures, cord compression and need for radiotherapy / surgery
  4. Paget’s disease: 1st line in metabolically active - reduce bone turnover and pain
36
Q

Bisphosphonates MOA

A
  • Reduces bone turnover by inhibiting osteoclasts (responsible for bone resorption)
  • Similar to naturally occuring pyrophosphate, so readily incorporated into bone
  • Bone is resorbed: bisphosphonates accumulate in osteoclasts
  • Inhibit activity and promote apoptosis
  • Net effect: reduction in bone loss, improvement in bone mass
37
Q

Bisphosphonates contraindications

A
  • Renal impairment
  • Hypocalcaemia
  • Oral admin in upper GI disorders
  • Smokers / major dental disease: risk of jaw osteonecrosis
38
Q

Bisphosphonates side effects

A
  • Oesophagitis (oral)
  • Hypophosphataemia
  • Jaw osteonecrosis: rare effect with high dose IV therapy
  • Atypical femoral fracture if on long-term
39
Q

Bisphosphonates interactions

A
  1. Calcium salts, antacids and iron salts: bisphosphonates binds
40
Q

Bisphosphonates patient info

A
  • Swallow whole at least 30 mins before breakfast with plenty of water
  • Remain upright for 30 mins after taking to reduce oesophageal irritation
41
Q

Calcium and Vitamin D indications

A
  1. Osteoporosis: ensure positive calcium balance when dietary intake ± sunlight exposure insufficient
  2. CKD: treat + prevent secondary hyperparathyroidism and renal osteodystrophy
  3. Severe hyperkalaemia: calcium gluconate used to prevent life-threatening arrhythmias
  4. Hypocalcaemia: Ca that is symptomatic or severe
  5. Vit D deficiency: Vit D used to prevent / treat including rickets and osteomalacia
42
Q

Calcium and Vitamin D MOA

A

-Calcium: essential for normal function of muscle, nerves, bone and clotting.
Homeostasis controlled by parathyroid hormone and vitamin D, which increase serum calcium and bone mineralisation, and calcitonin, which reduces serum calcium levels.

Osteoporosis: loss of bone mass increases risk of fracture. Restoring positiv calcium balance may reduce rate of bone loss.

CKD: impaired phosphate excretion and reduced vit D activation cause hyperphosphatemia and hypocalcaemia. This stimulates secondary hyperparathyroidism which leads to a range of bone changes = renal osteodystrophy. Treatment = oral calcium to bind phosphate in gut, or alfacalcidol to provide vit D that does not depend on renal activation.

Hyperkalemia: calcium raises myocardial threshold potential, reducing excitability and risk of arrhythmias

43
Q

Calcium and Vitamin D side effects

A

Oral ca: dyspepsia and constipation

Calcium gluconate: cardiovascular collapse if admin too fast, local tissue damage if accidentally given subcut

44
Q

Calcium and Vitamin D interactions

A

Oral calcium reduces absorption of many drugs: iron, bisphosphonates, tetracyclines, levothyroxine

Sodium bicarbonate: calcium gluconate cannot mix due to risk of precipitation