Glucose
Anhydrous Glucose
Some pharmacopoeias include anhydrous glucose and/or glu-
cose monohydrate as separate monographs whereas others
permit the anhydrous and/or monohydrate under a single
monograph.
Anhydrous Glucose (Ph. Bur.) is a white crystalline powder
with a sweet taste. Freely soluble in water; sparingly soluble
in alcohol.
Dextrose (USP 23), which is either anhydrous or the monohy-
drale. is a white odourless crystalline or granular powder or
colourless crystals with a sweet taste. Soluble I in I of water
and I in 100 of alcohol: very soluble in boiling water; soluble
in boiling alcohol.
Anhydrous glucose 0.9 g is approximately equivalent to glu-
cose monohydrate I g.
A 5.05% solution of anhydrous glucose in water is iso-
osmotic with serum.
Both Glucose Intravenous Infusion (BP 1998) and Dextrose
Injection (USP 23) may be prepared from either anhydrous
glucose or glucose monohydrate. However, the potency of the
BP preparation is expressed in terms of anhydrous glucose
whereas that of the USP is expressed in terms of glucose
monohydrate. The BP directs that yhen glucose is required as
a diluent for official injections or infravenous infusions, Glu-
cose Intravenous Infusion 5% should be used.
Adverse Effects and Precautions
Intravenous administration of glucose solutions
(particularly hyperosmotic solutions, which also
have a low pH) may cause local pain, vein irritation,
and thrombophlebitis, and tissue necrosis if extrava-
sation occurs. Some of these reactions may be due to
degradation products present after autoclaving or to
poor administration technique. Intravenous infusion
can lead to the development of fluid and electrolyte
disturbances including hypokalaemia, hypomagne-
saemia, and hypophosphatemia. Prolonged admin-
istration or rapid infusion of large volumes of iso-
osmotic solutions may cause oedema or water intox-
ication: conversely, prolonged or rapid administra-
tion of hyperosmotic solutions may result in
dehydration as a consequence of the induced hyper-
giveaemia.
The use of hyperosmotic glucose Solutions is contra-
indicated in patients with anuria, intracranial or in-
traspinal haemorrhage, and in delirium tremens
where there is dehydration.
It has been suggested that glucose solutions should
not be used after acute ischaemic strokes as hyper-
glycaemia has been implicated in increasing cere-
bral ischaemic brain damage and in impairing
recovery.
Glucose solutions should not be administered
through the same infusion equipment as whole
blood as haemolysis and clumping can occur.
Pregnancy. Glucose solutions are commonly employed as
hydrating fluids and as vehicles for the administration of other
dnigs. It has been suggested that if used during labour the glu-
cose load on the mother may lead to fetal hyperglycaemia.
hyperinsulinemia, and acidosis. with subsequent neonatal
hypoglycaemia and jaundice. Others' have found no evi-
dence of such an effect, and note that the number of patients
included in such reports is often small and the selection crite-
ria not homogeneous.
Stroke. It has been stated that glucose infusion should be
avoided after ischaemic stroke. Experimental and clinical
studies have purported to show that increased blood-glucose
concentrations worsen cerebral ischaemic brain damage and
impair recovery. The mechanism responsible is believed to be
the increase in ischaemic tissue of lactate with resultant aci-
dosis; the precise manner in which the lactate damages or im-
pairs recovery of tissue is not, however, known.
Pharmacokinetics
Glucose is rapidly absorbed from the gastro-intesti-
nal tract. Peak plasma concentrations of glucose oc-
cur about 40 minutes after oral administration of
glucose to hypoglycaemic patients. It is metabolised
via pynivic or lactic acid to carbon dioxide and wa-
ter with the release of energy. All body cells are ca-
pable of oxidizing glucose and it forms the principal
source of energy in cellular metabolism.
Uses and Administration
Glucose, a monosaccharide. is administered by
mouth or by intravenous infusion in the treatment of
carbohydrate and fluid depletion. It is the preferred
source of carbohydrate in parenteral nutrition regi-
mens and is used in oral rehydration solu-
tions for the prevention and treatment of
dehydration due to acute diarrhoeal diseases.
Glucose is also used in the treatment of hypoglycae-
niia (see below) and is administered orally in the
glucose tolerance test as a diagnostic aid for diabe-
tes mellitus .
The way in which the strengths of glucose solutions
for intravenous use are expressed varies in different
countries. Although the BP requires that the strength
be expressed in terms of anhydrous glucose, the
USP states that strengths are expressed in terms of
glucose monohydrate. Thus, the term glucose 5%
may represent, depending on origin, either 50 g per
litre of anhydrous glucose (equivalent to about 55 g
per litre of glucose monohydrate) or 50 g per litre of
glucose monohydrate (equivalent to about 45 g per
litre of anhydrous glucose). As the manner in which
such preparations are referred to in the medical lit-
erature is sometimes ambiguous, it has not always
been possible to state clearly in Martindale whether
the strengths of glucose solutions mentioned relate
to the anhydrous or hydrated form however, in Mar
tindale. unless otherwise specified, glucose inject-
ion is a 5% solution to distinguish it from more
concentrated forms. For many practical purposes it
is probably less important to know the exact way in
which the strength of a given concentration is ex-
pressed than to avoid confusion between completely
different strengths such as 5, 10, and 50% as the
more concentrated forms are associated with special
side-effects and precautions.
Glucose solution 5% (5.05% anhydrous, 5.51%
monohydrate) is iso-osmotic with blood and is the
strength often employed for fluid depletion: it may
be administered via a peripheral vein. Glucose solu-
tions with a concentration greater than 5% are
hyperosmotic and are generally used as a carbohy-
drate source; a 50% solution is often employed in
the treatment of severe hypoglycaemia (but see also
Hypoglycaemia, below). Hyperosmotic solutions
should generally be administered via a central vein
although some authorities have considered that con-
centrations up to 10% may be administered via a pe-
ripheral vein for short periods provided the site is
alternated regularly. In the emergency treatment of
hypoglycaemia it may be necessary to use a periph-
eral vein but the solution should be given slowly; a
suggested rate for glucose 50% in such circumstanc-
es is 3 mL per minute.
The dose of glucose is variable and is dependent on
individual patient requirements: serum-glucose con-
centrations may need to be carefully monitored. The
maximum rate of glucose utilisation has been esti-
mated to be about 500 to 800 mg per kg body-
weight per hour.
Strongly hyperosmotic glucose solutions (25 to
50%) have also been used to reduce cerebrospinal
pressure and cerebral oedema caused by de-
lirium tremens or acute alcohol intoxication
although they do not appear to be widely
employed. Glucose solution 50% has also been used
as a sclerosing agent in the treatment of varicose
veins and as an irritant to produce adhesive pleuritis.
Ectopic pregnancy. Ectopic pregnancy (implantation of the
fertilised ovum outside the womb) is now recognised at earli-
er stages as a result of improved diagnostic techniques. Sur-
gery remains the mainstay of treatment, but although
conservative surgical techniques may be employed in an at-
tempt to preserve fertility, nonsurgical methods have been in-
creasingly investigated. The best established therapy is
with methotrexate . but prostaglandins or hyperosmolar
glucose solutions have also been employed.
The local instillation of 10 to 20 mL of glucose 50% into un-
ruptured tubes has been found by Lang and associates to be a
safe and satisfactory alternative to combined therapy
consisting of dinoprost injected into the gestational sac,
sulprostone intramuscularly, and oestrogens to effect
luteolysis. No side-effects were reported by 16 women who
received glucose in this manner whereas 9 of 15 who received the
prostaglandins and oestrogens reported abdominal cramps
which ceased,only after discontinuation of sulprostone, 6 were
subfebrile,
and 2 had signs of imminent tubal rupture. It was believed that
the mechanism of action of hyperosmolar glucose in destroy-
ing the developing ectopic pregnancy was probably due to
necrobiosis by dehydrating the cells.
Thompson subsequently queried whether methotrexate was
likely to cause any more local damage to the fallopian tubes
than glucose. In reply Lang and Honigl still believed that
damage to the tubal wall with glucose was unlikely and addi-
tionally pointed out corrections to the urinary concentrations
of chorionic gonadotrophin as published in the original arti-
cle.
Haemodialysis-induced cramps. Suggestions that haemo-
dialysis-induced cramps are due to Hypovolaemia
are supported by the efficacy of volume expan-
sion with hypertonic solutions in the management of such
cramps. Intravenous infusion of 50 mL of glucose 50% solu-
lion has been used as an effective alternative to infusion of
sod chloride or mannitol.
Hyperkalaemia. Insulin, together with glucose to prevent
hypoglycaemia. is given to stimulate the cellular uptake of
potassium in the emergency treatment of moderate to severe
hyperkalaemia . Usually, 50 mL of glucose 50% is
administered,
Hypoglycaemia. Glucose is used to correct insulin-induced
hypoglycaemia, either by mouth or by
infusion of a hypertonic solution. For intravenous infusion up
to 50 mL of a 50% solution is given. Glucose 10 or 20% may
be used but larger volumes are required. Although 50% glu-
cose solution has been generally used to correct hypoglycae-
mia in children, some workers consider that so concentrated
a solution is associated with unacceptable morbidity and pos-
sible mortality, and that it should be replaced by the 10% so-
lution for this purpose. A 5 or 10% solution is used to prevent
the hypoglycaemia associated with insulin infusion for the
treatment of diabetic ketoacidosis. once blood-glucose con-
centration has fallen below 10 mmol per litre .
Myocardial infarction. Some results in diabetic and nondi-
abetic patients have suggested that the value of a glucose, in-
sulin, and potassium combination in patients with myocardial
infarction should perhaps be reconsidered, despite earlier fail-
ures .