BLOOD GLUCOSE LOWERING DRUGS›
BIGUANIDESMetformin hydrochloride 06-Jun-2017
lDRUG ACTIONMetformin 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.lINDICATIONS AND DOSE
Type 2 diabetes mellitus [monotherapy or in combination
with other antidiabetic drugs (including insulin)]
▶BY MOUTH USING IMMEDIATE-RELEASE MEDICINES
▶Child 8–9 years (specialist use only):Initially 200 mg once
daily, dose to be adjusted according to response at
intervals of at least 1 week, maximum daily dose to be
given in 2 – 3 divided doses; maximum 2 g per day
▶Child 10–17 years (specialist use only):Initially 500 mg
once daily, dose to be adjusted according to response at
intervals of at least 1 week, maximum daily dose to be
given in 2 – 3 divided doses; maximum 2 g per daylUNLICENSED USENot licensed for use in children under
10 years.
lCONTRA-INDICATIONSAcute metabolic acidosis (including
lactic acidosis and diabetic ketoacidosis)
lCAUTIONSRisk factors for lactic acidosis
CAUTIONS, FURTHER INFORMATION
▶Risk factors for lactic acidosisManufacturer advises caution
in chronic stable heart failure (monitor cardiac function),
and concomitant use of drugs that can acutely impair renal
function; interrupt treatment if dehydration occurs, and
avoid in conditions that can acutely worsen renal function,
or cause tissue hypoxia.
lINTERACTIONS→Appendix 1 : metformin
lSIDE-EFFECTS
▶Common or very commonAbdominal pain.appetite
decreased.diarrhoea (usually transient).gastrointestinal
disorder.nausea.taste altered.vomiting
▶Rare or very rareHepatitis.lactic acidosis (discontinue).
skin reactions.vitamin B12 absorption decreased
SIDE-EFFECTS, FURTHER INFORMATIONGastro-intestinal
side-effects are initially common with metformin, and may
persist in some patients, particularly when very high doses
are given. A slow increase in dose may improve
tolerability.
lPREGNANCYCan be used in pregnancy for both pre-
existing and gestational diabetes. Women with gestational
diabetes should discontinue treatment after giving birth.
lBREAST FEEDINGMay be used during breast-feeding in
women with pre-existing diabetes.
lHEPATIC IMPAIRMENTWithdraw if tissue hypoxia likely.
lRENAL IMPAIRMENTManufacturer advises avoid if
estimated glomerularfiltration rate is less than
30 mL/minute/ 1. 73 m^2.
Dose adjustmentsManufacturer advises consider dose
reduction in moderate impairment.
lMONITORING REQUIREMENTSDetermine 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).
lPATIENT AND CARER ADVICEManufacturer advises that
patients and their carers should be informed of the risk of
lactic acidosis and told to seek immediate medical
attention if symptoms such as dyspnoea, muscle cramps,
abdominal pain, hypothermia, or asthenia occur.
Medicines for Children leaflet: Metformin for diabetes
http://www.medicinesforchildren.org.uk/metformin-diabeteslMEDICINAL FORMS
There can be variation in the licensing of different medicines
containing the same drug. Forms available from special-order
manufacturers include: capsule, oral suspension, oral solution
Tablet
CAUTIONARY AND ADVISORY LABELS 21
▶Metformin hydrochloride (Non-proprietary)
Metformin hydrochloride 500 mgMetformin 500 mg tablets|
28 tabletP£ 1. 55 DT = £ 0. 90 | 84 tabletP£ 2. 16 – £ 2. 70 |
500 tabletP£ 16. 07
Metformin hydrochloride 850 mgMetformin 850 mg tablets|
56 tabletP£ 2. 56 DT = £ 1. 17 | 300 tabletP£ 6. 27 – £ 7. 13
▶Glucophage(Merck Serono Ltd)
Metformin hydrochloride 500 mgGlucophage 500 mg tablets|
84 tabletP£ 2. 88
Metformin hydrochloride 850 mgGlucophage 850 mg tablets|
56 tabletP£ 3. 20 DT = £ 1. 17
Oral solution
CAUTIONARY AND ADVISORY LABELS 21
▶Metformin hydrochloride (Non-proprietary)
Metformin hydrochloride 100 mg per 1 mlMetformin 500 mg/ 5 ml
oral solution sugar free sugar-free| 100 mlP£ 5. 85 – £ 10. 50
sugar-free| 150 mlP£ 60. 00 DT = £ 8. 78
Metformin hydrochloride 170 mg per 1 mlMetformin 850 mg/ 5 ml
oral solution sugar free sugar-free| 150 mlP£ 19. 95 DT = £ 19. 95
Metformin hydrochloride 200 mg per 1 mlMetformin 1 g/ 5 ml oral
solution sugar free sugar-free| 150 mlP£ 23. 48 – £ 24. 00 DT =
£ 24. 00
Powder
▶Metformin hydrochloride (Non-proprietary)
Metformin hydrochloride 1 gramMetformin 1 g oral powder sachets
sugar free sugar-free| 30 sachetPsBLOOD GLUCOSE LOWERING DRUGS›
SULFONYLUREASSulfonylureas f
lDRUG ACTIONThe sulfonylureas act mainly by augmenting
insulin secretion and consequently are effective only when
some residual pancreatic beta-cell activity is present;
during long-term administration they also have an
extrapancreatic action.
lCONTRA-INDICATIONSPresence of ketoacidosis
lCAUTIONSCan encourage weight gain (should be
prescribed only if poor control and symptoms persist
despite adequate attempts at dieting).G6PD deficiency
lSIDE-EFFECTS
▶Common or very commonDiarrhoea.gastrointestinal
discomfort.hypoglycaemia.nausea
▶UncommonHepatic disorders.vomiting
▶Rare or very rareAgranulocytosis.erythropenia.
granulocytopenia.haemolytic anaemia.leucopenia.
pancytopenia.thrombocytopenia
▶Frequency not knownAllergic dermatitis (usually in the
first 6 – 8 weeks of therapy).constipation.visual
impairment
lHEPATIC IMPAIRMENTJaundice may occur.
Dose adjustmentsSulfonylureas should be avoided or a
reduced dose should be used in severe hepatic impairment,
because there is an increased risk of hypoglycaemia.
lRENAL IMPAIRMENTSulfonylureas should be used with
care in those with mild to moderate renal impairment,
because of the hazard of hypoglycaemia. Care is required
to use the lowest dose that adequately controls blood
glucose. Avoid where possible in severe renal impairment.
lPATIENT AND CARER ADVICE
Driving and skilled tasksDrivers need to be particularly
careful to avoid hypoglycaemia and should be warned of
the problems.452 Diabetes mellitus and hypoglycaemia BNFC 2018 – 2019
Endocrine system6