Dibb Flashcards
(10 cards)
What is the mechanism of action and adverse effects of insulin and what are its uses
Mechanism of action: insulin binds to the alpha subunit of the insulin receptor which is a receptor tyrosine kinase, triggers autophosphorylation of beta subunits, phosphorylates insulin receptor substrates, activates PI3K Akt and MAP kinase pathways, causes rapid GLUT 4 translocation, inhibits hepatic glucose output, enhances glycogen synthesis and promotes potassium and amino acid uptake; Adverse effects: hypoglycaemia with autonomic and neuroglycopenic symptoms, local lipodystrophy, weight gain, oedema, very rare allergy or antibodies; Uses: essential in type 1 diabetes, diabetic ketoacidosis and hyperosmolar coma, gestational diabetes, severe stress or surgery in type 2 diabetes, when oral drugs fail, treatment of hyperkalaemia along with glucose
Mention various insulin types and formulations and enumerate their uses limitations and adverse effects
Rapid acting analogues lispro aspart glulisine act within ten minutes and last three to five hours and are used as premeal bolus; Short acting regular insulin starts in thirty minutes lasts six to eight hours and is used subcutaneously before meals and intravenously in ketoacidosis; Intermediate acting NPH or lente starts in one to two hours lasts twelve to eighteen hours and provides basal cover; Premixed 70 30 NPH regular is given twice daily for convenience; Long acting analogues glargine once daily and detemir twice daily give peakless basal insulin; Advantages of analogues are physiological profile and less nocturnal hypoglycaemia but cost is higher; Limitations and adverse effects are the same as regular insulin namely hypoglycaemia weight gain and local lipodystrophy
Classify oral antidiabetic drugs based on their mechanism of action and write pharmacotherapy of type two diabetes mellitus
Insulin secretagogues include sulfonylureas such as gliclazide and glimepiride and meglitinides such as repaglinide which close beta cell K ATP channels; Incretin based agents include DPP 4 inhibitors such as sitagliptin and GLP 1 receptor agonists such as exenatide; Drugs overcoming insulin resistance are metformin which activates AMPK and thiazolidinediones such as pioglitazone which activate PPAR gamma; Agents delaying glucose entry are alpha glucosidase inhibitors like acarbose and SGLT 2 inhibitors like dapagliflozin; Evidence based therapy starts with lifestyle and metformin then adds a second drug according to cost weight and hypoglycaemia risk then triple therapy and finally basal insulin if targets are not met
Describe the drug treatment of diabetic ketoacidosis
Give regular insulin intravenously at zero point one unit per kilogram bolus followed by the same rate per hour and double the rate if glucose fails to fall adequately, reduce rate when glucose reaches about three hundred milligrams per decilitre; Start isotonic saline one litre in the first hour then adjust and change to five per cent dextrose when glucose reaches target; Add potassium chloride ten to twenty milliequivalents per hour once urine flow is ensured and delay insulin if potassium is below three point three; Sodium bicarbonate fifty milliequivalents may be given only if arterial pH is below seven; Identify and treat precipitating factors and monitor vitals glucose and electrolytes closely
Write a short note on sulfonylureas
Second generation agents such as gliclazide modified release and glimepiride bind SUR1 subunit close K ATP channel and promote insulin release, lower HbA1c by about one to one point five percent and are inexpensive; Adverse effects are hypoglycaemia weight gain rash and rare agranulocytosis; Avoid in significant hepatic or renal impairment
Write a short note on biguanides or metformin
Metformin activates AMPK decreases hepatic gluconeogenesis increases peripheral glucose uptake and delays intestinal carbohydrate absorption, does not cause hypoglycaemia promotes weight reduction and is first line drug in type two diabetes and polycystic ovarian syndrome; Adverse effects include gastrointestinal intolerance vitamin B12 deficiency and rare lactic acidosis, contraindicated when estimated glomerular filtration rate is below thirty millilitres per minute and in hypoxic states
Write a short note on insulin secretagogues
Sulfonylureas provide prolonged insulin release but carry risk of late hypoglycaemia, meglitinides such as repaglinide and nateglinide act rapidly and briefly and are taken immediately before meals to control postprandial glucose with less fasting hypoglycaemia
Write a short note on insulin preparations
Insulin preparations are grouped into rapid acting analogues lispro aspart glulisine, short acting regular, intermediate acting NPH or lente, long acting glargine and detemir, and premixed combinations such as seventy thirty NPH regular; Regimens may be basal bolus multiple daily injections premixed twice daily or continuous subcutaneous infusion pump
Write a short note on antidiabetic drugs that overcome insulin resistance
Metformin reduces hepatic glucose production and improves peripheral uptake, pioglitazone activates PPAR gamma to enhance insulin sensitivity but may cause oedema weight gain and possibly bladder cancer and is avoided in heart failure, bromocriptine a dopamine agonist modestly lowers HbA1c by resetting hypothalamic rhythms
Write a short note on antidiabetic drugs that control postprandial hyperglycaemia
Rapid acting insulin analogues given at meal time blunt postprandial peaks, meglitinides repaglinide and nateglinide stimulate short insulin bursts before meals, alpha glucosidase inhibitors acarbose and voglibose delay carbohydrate digestion but may cause flatulence, GLP 1 receptor agonists and DPP 4 inhibitors enhance incretin effect with weight benefit and minimal hypoglycaemia
