Diabetic medications Flashcards
What are the types of diabetes?
Type 1: Absolute insulin deficiency
Type 2: Insulin deficiency/resistance
Type 3: Drug induced
Type 4: Gestational
What are the BM levels diagnostic of diabetes?
Random: >11
Fasting: >7
Glucose tolerance: >11
Where is insulin produced?
Beta cells in islets of Langerhan
What is the structure of insulin?
51 amino acids in 2 chains
2 disulphide bridges between chain A & B
Removal of C peptide from proinsulin produces insulin
What does insulin increase?
- Glucose uptake into muscle & fat
- Glycogen synthesis
- Fat synthesis
- Protein synthesis
- K+ uptake by cells
What does insulin decrease?
- Fat breakdown
- Ketone body synthesis
- Glycogen breakdown
- Gluconeogenesis
- Protein breakdown
What is the mechanism of action of sulphonylureas?
- Increase insulin release
- Displace bound insulin from pancreatic islet 13 cells
- Decrease peripheral insulin resistance
- Decrease glucagon secretion
- Decrease hepatic insulinase activity
What drugs inhibit Gliclazide?
Thiazides
Corticosteroids
Phenothiazines
What is the mechanism of action of Metformin?
- Decrease gluconeogenesis
- Increase peripheral insulin utilisation
- Delays glucose uptake from gut
How is Metformin excreted?
Unbound
Excreted unchanged in urine
How does Acarbose work?
- Delays intestinal glucose absorption
- Reduces post-prandial hyperglycaemia
How do Thiazolidinediones work?
Regulate genes involved in glucose & lipid metabolism improving insulin sensitivity
How do NSAIDs work?
- Inhibiting COX enzymes
- Block conversion of arachidonic acid to prostanoids thus more converted to leukotrienes
How does Acetazolamide work?
- Carbonic anhydrase inhibitor
- Act on proximal convoluted tubules
- Non-competitive inhibitors of enzyme affecting Na/H+ exchanger causing alkaline urine
What substances does activated charcoal not work against?
- Alcohol
- Metals
- Electrolytes
(polarised substances)
How does Mannitol work?
- Alcohol derivative of mannose
- Exerts osmotic effects resulting in inc in preload & CO
- Freely filtered at glomerulus acting as osmotic diuretic
How do Monoamine Oxidases work?
Found in liver bound to mitochondria
Catalyse oxidation of monoamines
Uses O2 molecule to remove amine group from drug
2 types: MAO-A & MAO-B
What are the 3 forms of COX?
- COX1: Constitutive found in most cells
- COX2: Inducible, found in macrophages & inflammatory cells
- COX3: Isoenzyme (CNS variant of COX1)
What are the causes of Tachyphylaxis?
- Change in receptor structure
- Loss of receptors
- Reduction in mediators
- Inc in breakdown of drug
- Physiological adaptation
