Diabetes Pharmacology Flashcards
What is an OHA?
Oral Hypoglycaemic Agent.
What are the classes of OHAs?
- Biguanides
- Sulfonylureas
- thiazolidinediones (TZD)
- Alpha glucosidase Inhibitors
- Incretin-enhancing drugs
What group does Metformin belong to?
Biguanides (1st line treatment)
How does Metformin work?
- slows glucose absorption in the intestines
- stops glucose production in the liver from lactate molecules
- increase receptors in muscle and fat cells, this increases the uptake of glucose through enhanced insulin receptor binding.
What is metformin prescribed for?
TIIDM that is uncontrolled by lifestyle factors.
True/False: Metformin causes weight gain.
False
True/False: Metformin does NOT increase insulin secretion
True. So hypoglycaemia is rare with monotherapy.
Metformin affects Vit B12 absorption, what does this mean?
Anaemia - can effect brain and nerve function.
Baseline levels should be taken and rechecked periodically.
What is an uncommon, but potentially fatal adverse reaction to Metformin?
MALA - Metformin Associated Lactic Acidosis.
What are the risk factors for MALA?
Dehydration, alcohol consumption, renal/hepatic impairment, CVD, hypoxemia, elderly
What are the S/S of Acidosis?
headache, sleepiness, confusion, LOC, seizures, weakness, diarrhoea, SOB, cough, arrhythmias, tachycardia, N&V
Why should metformin dose be increased slowly?
To reduce GI upset.
How long does glucose control take when on Metformin?
up to 2 weeks. BGL should be monitored regularly.
If pt is having IV iodinated contrast, what drug should be withheld?
Metformin.
Severe renal disease is a contraindication for what OHAs?
Biguanide and SFU.
What class of drugs is the 2nd line OHA?
Sulfonylureas (SFU) The -ides
What are long acting SFU?
Glibenclamide
Glimepiride.
What are short acting SFU?
Gliclazide
Glipizide
What is the mode of action for SFU?
Stimulate B cells to release insulin.
Block glucose formation in the liver
Increase cellular sensitivity to insulin
SFU can result in weight _____
gain.
What are contraindications to SFU?
Renal impairment, allergy to other SFU - thiazide, loop diuretics, celecoxib.
True/False: Long acting SFU should not be given to those who are elderly or have renal/hepatic impairment.
True.
When taking SFU what reduces the chance of a hypo?
Taking dose with food.
SFU and TZD should be used with caution in those who are ____
obese.
From what group of drugs is TZD?
OHA - Thiazolidinedione or ‘glitazones’ (-zones)
What is Pioglitazone?
A TZD.
What are TZD used for?
Those who do not tolerate metformin or SFU.
What needs to be monitored when TZD is prescribed?
Weight gain (oedema), BGL, CVS, Hb, lipids, liver function.
What OHA reduces the effectiveness of oral contraceptive?
TZD.
What co-morbidities are contraindicated for TZD use?
obesity, CHF, HTN, family hx of bladder cancer
What can be used when OHAs are not tolerated and if BGL remains high over meals despite OHA use?
Alpha-Glucosidase Inhibitors (Acarbose)
How does Acarbose work?
blocks/slows breakdown of carbs from a meal (reduces postprandial rise of glucose)
What drug must be taken with the first bite of food?
Acarbose
If rescue for a hypo is needed when taking acarbose, what should be used?
Pure glucose.
Adverse effects of Acarbose use?
Bloating, flatulence, abdominal pain.
What are the contraindications for Acarbose?
Inflammatory bowel disease, colonic ulceration, partial intestinal obstruction, chronic intestinal diseases.
What are the 2 incretin-enhancing drugs?
GLP-1 analogue (exenatide) and DPP4 inhibitor (saxagliptin)
What are the major concerns of GLP-1 analogues?
SC only - monitor site
Hx or acute pancreatitis.
What are the major concerns of DPP4 inhibitors?
URTI
What do incretin-enhancing drugs do?
Trigger the release of insulin when BGL is high.
What are medications that INCREASE BGL?
Beta agonists, corticosteroids, thiazides diuretics, OC
What are medications that DECREASE BGL?
beta-blockers, NSAIDs, ACEI, Alcohol
Types of insulin and their duration.
Rapid (Aspart, Glulisine, lispro) 4hrs
Short (regular, neutral) 8hrs
Intermediate (NPH, isophane, protamine) 12+hr
Long (glargine, detemir) 24hr
What type of insulin is Aspart?
Rapid
What type of insulin is protamine?
Intermediate
What type of insulin is detemir?
Long
What does insulin do?
Regulate the uptake and utilization of glucose.
When might insulin be needed in TIIDM?
temporarily during illness or surgery or if OHA cannot regulate BGL.
What are some important points regarding insulin preparation and administration?
Mixed by rolling.
Unopened store on side in fridge.
Opened store at room temp for 1 month.
Parental only as if taken orally peptides destroyed in the stomach by digestive enzymes.
What can cause a hypo when taking insulin?
Eating too little, incorrect dose, increased physical activity.
What can cause a hyper when taking insulin?
increased caloric intake, incorrect dose, emotional, stress, infections, surgery, pregnancy and illness.
Signs of a hyperglycaemic event?
vomiting, headache, dehydration, SOB, stomach ache, polyuria.
What increases insulin absorption?
Injection into massaged/exercised area.
Higher temperature
What reduces insulin absorption?
Smoking, using an injection site too many times, cold insulin.
