Ian,
Glycomin = Glibenclamide, a sulphonylurea
metaformin is a Biguanides , a different class of drug. any idea why he changed you over? do you have a renal or hepatic impairment?
The main problem of metaformin is "digestive upsets" ie loose bowels
which can be countered by the slow release version
The notes in BNF are :
Metformin, the only available biguanide, has a different mode of action from the sulfonylureas, and is not interchangeable with them. It exerts its effect mainly by decreasing gluconeogenesis and by increasing peripheral utilisation of glucose; since it acts only in the presence of endogenous insulin it is effective only if there are some residual functioning pancreatic islet cells.
Metformin is the drug of first choice in overweight patients in whom strict dieting has failed to control diabetes, if appropriate it may also be considered as an option in patients who are not overweight. It is also used when diabetes is inadequately controlled with sulfonylurea treatment. When the combination of strict diet and metformin treatment fails, other options include:
combining with a sulfonylurea (section 6.1.2.1) (reports of increased hazard with this combination remain unconfirmed);
combining with pioglitazone (section 6.1.2.3);
combining with repaglinide or nateglinide (section 6.1.2.3);
combining with linagliptin, saxagliptin, sitagliptin, or vildagliptin (section 6.1.2.3);
combining with exenatide or liraglutide (section 6.1.2.3);
combining with acarbose (section 6.1.2.3), which may have a small beneficial effect, but flatulence can be a problem;
combining with insulin (section 6.1.1) but weight gain and hypoglycaemia can be problems (weight gain minimised if insulin given at night).
Insulin treatment is almost always required in medical and surgical emergencies; insulin should also be substituted before elective surgery (omit metformin on the morning of surgery and give insulin if required).
Hypoglycaemia does not usually occur with metformin; other advantages are the lower incidence of weight gain and lower plasma-insulin concentration. It does not exert a hypoglycaemic action in non-diabetic subjects unless given in overdose.
Gastro-intestinal side-effects are initially common with metformin, and may persist in some patients, particularly when very high doses such as 3 g daily are given.
Very rarely, metformin can provoke lactic acidosis. It is most likely to occur in patients with renal impairment, see Lactic Acidosis below.
Metformin is used for the symptomatic management of polycystic ovary syndrome [unlicensed indication]; however, treatment should be initiated by a specialist. Metformin improves insulin sensitivity, may aid weight reduction, helps to normalise menstrual cycle (increasing the rate of spontaneous ovulation), and may improve hirsutism.
METFORMIN HYDROCHLORIDE
Additional information
interactions (Metformin).
Indications
diabetes mellitus (see notes above); polycystic ovary syndrome [unlicensed indication]
Cautions
see notes above; determine renal function before treatment and at least annually (at least twice a year in patients with additional risk factors for renal impairment, or if deterioration suspected); interactions: Appendix 1 (antidiabetics)
Lactic acidosis
Use with caution in renal impairment—increased risk of lactic acidosis; avoid in significant renal impairment. NICE(1) recommends that the dose should be reviewed if eGFR less than 45 mL/minute/1.73 m2 and to avoid if eGFR less than 30 mL/minute/1.73 m2. Withdraw or interrupt treatment in those at risk of tissue hypoxia or sudden deterioration in renal function, such as those with dehydration, severe infection, shock, sepsis, acute heart failure, respiratory failure or hepatic impairment, or those who have recently had a myocardial infarction
Contra-indications
ketoacidosis, see also Lactic Acidosis above; use of general anaesthesia (suspend metformin on the morning of surgery and restart when renal function returns to baseline)
Iodine-containing X-ray contrast media
Intravascular administration of iodinated contrast agents can cause renal failure, which can increase the risk of lactic acidosis with metformin—see Lactic Acidosis above. Suspend metformin prior to the test; restart no earlier than 48 hours after the test if renal function has returned to baseline
Hepatic impairment
withdraw if tissue hypoxia likely
Renal impairment
see under Cautions
Pregnancy
used in pregnancy for both pre-existing and gestational diabetes—see also section 6.1.2
Breast-feeding
may be used during breast-feeding—see section 6.1.2
Side-effects
anorexia, nausea, vomiting, diarrhoea (usually transient), abdominal pain, taste disturbance, rarely lactic acidosis (withdraw treatment), decreased vitamin-B12 absorption, erythema, pruritus and urticaria; hepatitis also reported
Dose
Diabetes mellitus, adult and child over 10 years initially 500 mg with breakfast for at least 1 week then 500 mg with breakfast and evening meal for at least 1 week then 500 mg with breakfast, lunch and evening meal; usual max. 2 g daily in divided doses
Polycystic ovary syndrome [unlicensed], initially 500 mg with breakfast for 1 week, then 500 mg with breakfast and evening meal for 1 week, then 1.5–1.7 g daily in 2–3 divided doses
I never in my life being able to swallow medicine whole and I did ask the Doc and was advised any way I can e.g crush or chew so that's a relief :thumbup: so now i just have to worry about how the body will react to the change so I will keep you posted so if you don't hear from me you will know the side effects were servere
