Anti-Diabetic Medications in Type 2 Diabetes Flashcards
What are the actions of insulin?
Induces glucose uptake and utilisation by cells
Promotes removal of glucose from blood
Promotes formation of glycogen and conversion of glucose into fat and adipose tissue
Stimulates amino acid uptake by cell and protein formation
What is type 2 diabetes?
State of insulin deficiency
What causes type 2 diabetes?
Resistance to insulin’s action at target tissues
Abnormal insulin secretion
Inappropriate liver gluconeogenesis
Obesity
What is the aim of non-pharmacological treatments for type 2 diabetes?
Optimise blood glucose and decreased possible complications
What is the first line treatment for type 2 diabetes?
Positive lifestyle changes = stop smoking, modify diet, maintain ideal body weight, exercise
What are the basics of drug treatment?
Insulin dependent = increasing insulin secretion
Insulin independent = slowing glucose absorption from kidneys and enhancing glucose excretion by kidneys
What are some insulin dependent drugs?
Sulphonylureas, incretin mimetics, glinides, DPP4-inhibitors
What are some insulin independent drugs?
Alpha glucosidase inhibitors, SGLT2 inhibitors
What is cellular energy status linked to?
Insulin secretion in pancreatic beta cells
What does elevation in blood glucose cause?
Increased diffusion of glucose into beta cells by GLUT 2 facilitated transport
What phosphorylates glucose once it enters the cell?
Glucokinase = glucose-6-phosphate then undergoes glycolysis in mitochondria, yielding ATP
What causes membrane depolarisation?
The closure of KATP channels due to the increased ATP/ADP ration within the cell
What does depolarisation of the cell membrane cause?
Opens voltage activated Ca2+ channels = increases intracellular Ca2+ which triggers insulin secretion
What are sulphonylureas?
Insulin secretagogues = require a functional mass of beta cells to be effective, efficacy may wane with time
What are some examples of sulphonylureas?
All contain sulphonylurea group = tolbutamide, glibenclamide, gliclazide, glipizide
How do sulphonylureas work?
Displace the binding of ADG-Mg2+ from the SUR1 subunit = closes KATP channel and stimulates insulin release
What are some long and short acting sulphonylureas?
Long acting = glibenclamide, glipizide
Short acting = tolbutamide, gliclazide
What is a benefit of sulphonylureas?
Reduce microvascular complications
How do sulphonylureas cause hypoglycaemia?
By excess insulin secretion = associated with long acting agents, elderly patients, patients with reduced hepatic/renal disease and chronic kidney disease
When are sulphonylureas used as a first line treatment?
In patients intolerant to metformin, or with weight loss
How are sulphonylurease used as a second line treatment?
In conjunction with metformin
What is the third line use of sulphonylureas?
In conjunction with metformin and thiazolidinediones (or other drugs)
Why do sulphonylureas cause weight gain?
Anabolic effect of insulin is increased, appetite increased, urinary loss of glucose decreased
In what patients should long acting sulphonylureas be avoided?
In patients with renal impairment, the elderly and in pregnancy
How do glinides (meglinitinides) work?
Action similar to SUs but augmented by glycaemia = bind to SUR1 at distinct benzamido site close to KATP channel and trigger insulin release
What are some examples of glinides?
Lack sulphonylurea group = repaglinide, nateglinide
How are glinides administered?
Active orally = rapid onset (30-60mins)/offset (4hrs) kinetics and promote insulin secretion in response to meals
What are the benefits of glinides?
Reduce postprandial blood glucose and are less likely to cause hypoglycaemia than long acting SUs
What drugs can glinides be used in conjunction with?
Metformin and thiazolidinediones