This information is provided by
Provet for educational purposes only.
You should seek the advice of your
veterinarian if your pet is ill as only he or she can correctly advise on the
diagnosis and recommend the treatment that is most appropriate for your pet.
The use of oral hypoglycemic drugs
is limited to Type II (non-insulin dependent) diabetes mellitus. Recent studies suggest that some of
these drugs may be beneficial in the management of Type II diabetes mellitus
Oral hypoglycemic agents are widely used in human medicine
for the management of non-insulin dependent diabetes mellitus (NIDDM) patients
who can not be managed by diet alone. They should not be given to patients
with insulin dependent diabetes mellitus (IDDM). Patients with long standing
NIDDM often require insulin in addition to hypoglycemic drugs.
Dogs invariably develop Type 1 (insulin dependent) diabetes mellitus which
be treated solely using oral hypoglycemic drugs. Cats on the other hand usually have
Type II (non-insulin dependent) diabetes mellitus and recent studies suggest that
some oral hypoglycemics
may be of use in the management of these cases.(See also Diabetes
- a-glucosidase inhibitors
These drugs (eg acarbose) reduce starch and disaccharide absorption from
the brush border by inhibiting the action of the enzyme a-glucosidase
and they reduce post-prandial hyperglycemia. Acarbose does not stimulate
insulin release from the pancreas nor does it increase peripheral activity
of insulin in tissues. So, acarbose does not cause hypoglycemia.
Acarbose is used in human medicine for the treatment of patients
with NIDDM and as an adjunct to insulin in IDDM. It is given to obese human patients which are in a
pre-NIDDM state. However, it causes unacceptable side-effects including
flatulence, bowel cramps and diarrhoea. In dogs it has been used at 25-100 mg twice daily by mouth
and has been reported to improve
control of hyperglycemia when given with insulin in some cases of diabetes
mellitus. Unfortunately, dogs develop a dose-dependent diarrhoea.
In cats acarbose has been given at a dose of 12.5-25mg/cat with food. By
itself it only reduces hyperglycemia to the range 250-300mg/dl but it is reported to
work well when given with insulin. As in humans, flatulance, and loose stools have been
reported to occur.
Like acarbose, these products (eg metformin) do not stimulate insulin
secretion from the pancreas and so the risk of hypoglycemia is less than
with the use of sulfonylureas. Metformin can be used by itself or in
combination with sulfonylureas and it acts mainly by inhibiting
gluconeogenesis in the liver, but also by delaying glucose absorption from
the gastrointestinal tract and increasing glucose uptake by peripheral
tissues. It reduces LDL and VLDL cholesterol concentrations in the
blood, whilst increasing HDL cholesterol.
Metformin is not metabolised and is excreted via the kidneys. Side
-effects include weight loss, gastrointestinal problems, reduced vitamin B12
absorption and rarely, a potential fatal lactic acidosis. It is
contra-indicated in renal and hepatic insufficiency.
There are no reports of the use of these products in cats or dogs.
The sulfonylureas (eg tolbutamide, glyburide and glipizide) have the
following mechanisms of action :
- They stimulate insulin release from the b-cells
of the pancreas
- They reduce glucagon concentrations in the blood
- They increase tissue receptor binding of insulin
These drugs are metabolised by the liver and excreted via the liver and
kidneys, and they are contraindicated in renal and hepatic insufficiency.
They are also contraindicated in pregnancy as they cross the placenta and
can cause depletion of insulin from the fetal pancreas.
Sulfonylureas (glipizide) have been used in cats:
- In one study involving 20 cats with NIDDM a long term response was
achieved in 55%
- In another study involving 50 cats with NIDDM a success rate of 38%
- About 15% of cats develop vomiting
- 10% develop signs of liver injury - including jaundice and increased
serum liver enzymes within 4 weeks of treatment being started.
- Hypoglycemia occurs in about 15% of the cats which respond to
- Cats without significant side-effects can be treated for life.
- Glipizide loses efficacy (time varies from weeks to years) in about
10% of cats
- Glipizide dose : 2.5mg/cat twice daily with food. If no side-effects
after 2 weeks increase dose to 5mg/cat twice daily.
- Monitor glucose tolerance and screen for evidence of liver damage.
Stop treatment if side-effects occur.
- If get no clinical response after 12 weeks stop glipizide and start
- If get reduced clinical signs, no glycosuria and blood glucose
concentrations of < 200mg/dl glipizide should be stopped. If
hyperglycemia recurs it can be restarted at half the original dose
- Normoglycemia can last for more than 12-14 months following a course
of successful glipizide therapy.
- 3 monthly checks are advised.
- Glycosylated hemoglobin and fructosamine concentrations are good
indicators of glycemic control.
4. Transition Metals
Vanadium and chromium are used as oral hypoglycemic agents. Studies in
cats have shown :
- 0.2mg/kg/day oral vanadium (Vanadyl Fuel) decreased blood glucose
concentrations and removed clinical signs in cats with early NIDDM.
Compared to a placebo controlled group the treated group gained weight,
clinical signs resolved and serum fructosamine concentrations decreased.
- Chromium has also been used at 200mg/cat
once daily by mouth.
These agents (eg troglitazone) increase peripheral tissue sensitivity to
insulin, reverse insulin resistance and improve glucose and lipid
homeostasis. They do not increase insulin secretion from the pancreas.
Troglitazone has been used in cats (at a dose of 200mg/cat once daily)
but there were no observed improvements in glucose concentration or in
If oral hypoglycemic drugs are to be used
effectively in the management of Type II NIDDM in cats, they should be given
to non-ketoacidotic cats with stable diabetes, mild signs and a normal
weight or slightly overweight body condition. Obese animals should be placed
on a weight-reduction programme.
Updated October 2013