lHEPATIC IMPAIRMENTUse with caution in hepatic
impairment (delayed response).
lPATIENT AND CARER ADVICE
Driving and skilled tasksDrowsiness may affect the
performance of skilled tasks (e.g. driving).
lMEDICINAL FORMS
There can be variation in the licensing of different medicines
containing the same drug.
Capsule
CAUTIONARY AND ADVISORY LABELS 21
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Metyrapone 250 mgMetopirone 250 mg capsules|
100 capsuleP£ 363. 66
3 Diabetes mellitus and
hypoglycaemia
3.1 Diabetes mellitus
Diabetes 05-Jun-2017
Description of condition
Diabetes mellitus is a group of metabolic disorders in which
persistent hyperglycaemia is caused by deficient insulin
secretion or by resistance to the action of insulin. This leads
to the abnormalities of carbohydrate, fat and protein
metabolism that are characteristic of diabetes mellitus.
Type 1 diabetes mellitus below and Type 2 diabetes
mellitus p. 448 are the two most common classifications of
diabetes. Other common types of diabetes are gestational
diabetes (develops during pregnancy and resolves after
delivery) and secondary diabetes (may be caused by
pancreatic damage, hepatic cirrhosis, or endocrine disease).
Treatment with endocrine, antiviral or antipsychotic drugs
may also cause secondary diabetes. In children, conditions
such as cysticfibrosis can lead to diabetes; monogenic
diabetes (previously known as maturity onset diabetes in the
young) can also occur due to a single gene defect.
Driving
Information on the requirements for driving vehicles by
young people receiving treatment for diabetes is available in
the BNF or from the DVLA atwww.gov.uk/guidance/diabetes-
mellitus-assessing-fitness-to-drive.
Alcohol
Adolescents and their carers should be made aware that
alcohol can make the signs of hypoglycaemia less clear, and
can cause delayed hypoglycaemia; (note: specialist sources
recommend thatadultpatients with diabetes should drink
alcohol only in moderation, and when accompanied by food).
Oral glucose tolerance tests
The oral glucose tolerance test is used mainly for diagnosis
of impaired glucose tolerance; it isnotrecommended or
necessary for routine diagnostic use of diabetes when severe
symptoms of hyperglycaemia are present. In children who
have less severe symptoms and blood-glucose levels that do
not establish or exclude diabetes (e.g. impaired fasting
glycaemia), an oral glucose tolerance test may be required. It
may be useful for diagnosis of monogenic diabetes or cystic
fibrosis related diabetes, and is used to establish the
presence of gestational diabetes.
An oral glucose tolerance test involves measuring the
blood-glucose concentration after fasting, and then 2 hours
after drinking a standard anhydrous glucose drink.
Anhydrous glucose may alternatively be given as the
appropriate amount ofPolycal®or asRapilose®OGTT oral
solution.HbA1c measurement
Glycated haemoglobin (HbA 1 c) forms when red blood cells
are exposed to glucose in the plasma. The HbA 1 ctestreflects
average plasma glucose over the previous 2 to 3 months and
provides a good indicator of glycaemic control. Unlike the
oral glucose tolerance test, an HbA 1 c test can be performed
at any time of the day and does not require any special
preparation such as fasting.
HbA 1 c values are expressed inmmol of glycated
haemoglobin per mol of haemoglobin (mmol/mol),a
standardised unit specific for HbA 1 c created by the
International Federation of Clinical Chemistry and
Laboratory Medicine (IFCC). HbA 1 c values were previously
aligned to the assay used in the Diabetes Control and
Complications Trial (DCCT) and expressed as a percentage.Equivalent valuesIFCC-HbA 1 c (mmol/mol) DCCT-HbA 1 c(%)
42 6. 0
48 6. 5
53 7. 0
59 7. 5
64 8. 0
69 8. 5
75 9. 0The HbA 1 c test is used for monitoring glycaemic control in
both Type 1 diabetes and Type 2 diabetes in children, and for
diagnosis of Type 2 diabetes in adults.gHbA 1 c should
not be used to diagnose diabetes in children.h
HbA 1 c is also a reliable predictor of microvascular and
macrovascular complications and mortality. Lower HbA 1 cis
associated with a lower risk of long term vascular
complications, and children and their carers should be
supported to aim for an individualised HbA 1 c target (see
Type 1 diabetes below and Type 2 diabetes p. 448 ).g
HbA 1 c should usually be measured in children with type 1
and type 2 diabetes every 3 months; and more frequently in
children with type 1 diabetes if blood-glucose is poorly
controlled.h
HbA 1 c monitoring is invalid in children with disturbed
erythrocyte turnover or in children with a lack of, or
abnormal haemoglobin (for example, any anaemia, a recent
blood transfusion, or an altered red cell lifespan). In these
cases, quality-controlled plasma glucose profiles, total
glycated haemoglobin estimation (if there is abnormal
haemoglobin), or fructosamine estimation can be used.
Laboratory measurement of fructosamine concentration
measures the glycated fraction of all plasma proteins over
the previous 14 to 21 days but is a less accurate measure of
glycaemic control than HbA 1 c.Type 1 diabetes 05-Jun-2017
Description of condition
Type 1 diabetes describes an absolute insulin deficiency in
which there is little or no endogenous insulin secretory
capacity due to destruction of insulin-producing beta-cells
in the pancreatic islets of Langerhans. This form of the
disease has an auto-immune basis in most cases, and it can
occur at any age, but most commonly before adulthood.
Loss of insulin secretion results in hyperglycaemia and
other metabolic abnormalities. If poorly managed, theBNFC 2018 – 2019 Diabetes mellitus 445
Endocrine system6