eg, metformin & phenformin.
PHARMACOKINETICS
- Given orally, Not bind to plasma proteins
- Not metabolized
- Excreted unchanged in urine
Mechanism of action :
- they — glucose absorption from GIT.
- they ++ glucose uptake by the tissues ⇒ anaerobic glycolysis → lactic acid
- — serum glucagon.
- ++ no. & affinity of insulin receptors.
- — hepatic gluconeogenesis.
Uses
- Type 2 DM either alone (in mild cases) or in combination with other drugs (SU).obese pt with t2dm
- to enhance weight loss in overweight patient
- with insulin in case of insulin resistance.
Polycystic ovary syndrome; it lowers serum androgens and restores normal menstrual cycles and ovulation.
Advantages of Metformin over SUs
Does not cause hypoglycemia ( why ? ) ( Ideal for obese pts) Does not result in wt gain ( why ? )
Side effects:
- Anorexia, vomiting, diarrhoea.
- Metallic taste.
- ↓ Absorption of vitamin B12 (→ Megaloblastic anaemia).
- Lactic acidosis: common e phenformin and less e metformin; especially in renal or hepatic diseases. Lactic acidosis (rare but fatal in 50% of cases)
Contraindicated in liver and renal dysfunction