Metformin Flashcards
Metformin - indications
First-line for T2DM
Metformin - MOA
Acts primarily by REDUCING HEPATIC GLUCOSE OUTPUT (gluconeogenesis and glycogenolysis) - it does this via the activation of adenosine monophosphate activated protein kinase (AMP kinase)
Metformin - side effects (common)
- Nausea +/- Vomiting
- Diarrhoea
- Taste disturbance
- Anorexia
Metformin - side effects (rare)
Lactic acidosis is a very rare side effect
note - this would present as metabolic acidosis (low pH low HCO3-)
warn patients if they experience any new SOB, chest pain, fever to seek medical attention
Metformin - contraindications (completely avoid)
- acute kidney injury
- severe tissue hypoxia
Metformin - cautions (3)
- renal impairment
- hepatic impairment
- acute alcohol intoxication (temporarily withold)
- chronic alcohol abuse (due to hypoglycaemic risk)
Metformin use in patients with renal impairment - how should this be monitored?
monitor patients eGFR
if eGFR <45 - reduce dose
if eGFR <30 - stop drug use
Metformin - interactions
IV CONTRAST MEDIA (e.g.- for ct scans w/contrast)
metformin should be witheld before and 48hrs after iv contrast media
Metformin - administration
best started at low dose to minimise adverse effects and then gradually increase:
1) 500mg OD with breakfast (for 1 week)
2) 500mg BD
(for 1 week)
3) 500mg TDS
(for 1 week)
4) 500mg QDS
In the end patients on max dose metformin will be taking 4 tablets total in a day (2g daily)
TAKE WITH/AFTER FOOD to minimise GI upset
Explaining diagnosis of T2DM to patient and treatment
Type 2 diabetes is a common condition that causes the level of sugar (glucose) in the blood to become too high.
It’s caused by problems with a chemical in the body (hormone) called insulin. This chemical is usually responsible for lowering your glucose to make sure the level stays within range but what happens in diabetes is your body does not respond properly to this hormone so your glucose levels get too high. It’s often linked to being overweight or inactive, or having a family history of type 2 diabetes.
This is why it is important to combine both lifestyle factors (exercise, diet) as well as medication.
Diabetes can cause you to have symptoms such as increased thirst and increased urination. The medication will help control the levels of glucose in your body and therefore overtime reduce your symptoms.
If diabetes is left untreated it can lead to further complications such as eye problems, organ damage, cancers, nerve damage and heart attacks/stroke.
Monitoring and stepwise treatment of T2DM
Review HbA1c every 3-6 months until levels are stable
Monotherapy metformin - target HbA1c is <48
If HbA1c is >58 on metformin monotherapy then ADD second drug - this will then have a target HbA1c of <53
Also check renal function prior to starting medical and annually - measure more frequently in renally impaired patients
T2DM patient is on max dose metformin. Their recent HbA1c is 60 and the patient is overweight. What is the most appropriate medication to add to their treatment?
Gliptin (e.g.- sitagliptin)
T2DM patient is on max dose metformin. Their recent HbA1c is 59 and the patient has a PMHx of heart failure and CKD. What is the most appropriate medication to add to their treatment?
SGLT-2 Inhibitor (any medication that ends in FLOZIN)
Why is this the answer?
SGLT-2 inhibitors work especially well in patients with heart failure and diabetes – cardioprotective and nephroprotective
Can also be used to treat CKD with increased ACR, diabetes and heart failure
Which diabetes medications are known to cause hypoglycaemia?
Sulfonylureas (e.g.- gliclazide)
Insulin
Which patients cannot have their blood glucose monitored via HbA1c AND what do we use instead?
Patients who have sickle cell disease OR severe thalassaemia CANNOT have HbA1c checked – instead these patients should have a fasting blood glucose test
