ADMINISTRATION ROUTES:
PO
ALTERNATIVE NAMES:
Arrow Metformin
ICU INDICATIONS:
- Type 2 diabetes mellitus
PRESENTATION AND ADMINISTRATION:
PO:
Metformin 250 mg, 500 mg, 850 mg and 1000 mg tablets
DOSAGE:
PO:
500 mg OD or BD
Increase to max 1000 mg TDS
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Dose in renal impairment
| GFR (ml/min) | DOSE |
|---|---|
| <10 | do not use |
| 10-40 | do not use |
| >40-50 | 25-50% of dose |
Dose in renal replacement therapy
| MODALITY | DOSE |
|---|---|
| CAPD | do not use |
| HD | do not use |
| CVVHDF | do not use |
DOSAGE IN PAEDIATRICS:
PO:
Not applicable
CLINICAL PHARMACOLOGY:
Metformin is an antihyperglycaemic agent which improves glucose tolerance in patients with Type 2 diabetes, lowering both basal and postprandial plasma glucose. Its pharmacologic mechanisms of action are different from other classes of oral antihyperglycaemic agents. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization.
CONTRAINDICATIONS:
- Renal dysfunction
- Congestive heart failure requiring pharmacologic treatment
- Known hypersensitivity to metformin
- Acute or chronic metabolic acidosis including diabetic ketoacidosis
- Use of intravenous contrast for angiography or CT if eGFR <30 mL/min
WARNINGS:
Lactic Acidosis
Lactic acidosis is a rare, but serious, metabolic complication that can occur due to metformin accumulation. When it occurs, it is fatal in approximately 50% of cases
PRECAUTIONS:
General:
Surgical Procedures
Metformin therapy should be temporarily suspended for any surgical procedure (except minor procedures not associated with restricted intake of food and fluids) and should not be restarted until the patient's oral intake has resumed and renal function has been evaluated as normal.
Hypoglycaemia
Hypoglycaemia does not occur in patients receiving metformin alone under usual circumstances of use, but could occur when caloric intake is deficient, when strenuous exercise is not compensated by caloric supplementation, or during concomitant use with other glucose-lowering agents (such as sulfonylureas and insulin)
Laboratory Tests:
No tests in addition to routine ICU tests are required
Drug/Laboratory Test Interactions:
None noted
IMPORTANT DRUG INTERACTIONS IN ICU:
None of note
ADVERSE REACTIONS:
Gastrointestinal:
Diarrhoea, nausea, vomiting, flatulence, abdominal discomfort
Metabolic and endocrine:
Lactic acidosis, hypoglycaemia