These agents are most widely used in patients with refractory obesity who have
ineffective insulin action.
The thiazolidinediones consist of troglitazone (5.124), rosiglitazone (5.125), and
pioglitazone (5.126). Shortly after its initial marketing troglitazone was discontinued,
initially in the USA and UK, because of more than 60 cases of liver failure or death.
These agents work by enhancing target tissue insulin sensitivity by increasing glucose
uptake and metabolism in muscle and adipose tissues. Thiazolidinediones are eug-
lycemic agents, which when used alone (“monotherapy”) can reduce glucose levels to
the normal range without causing hypoglycemia. They can also be used in combination
with either biguanides or sulfonylureas. They should not be used in people with liver
disease. The α-glucosidase inhibitors include acarbose (5.127) and miglitol (5.128).
These agents are competitive inhibitors of the α-glucosidase enzyme and thus modify
the digestion and absorption of starch and disaccharides from the gut.
5.20.1.3 Insulin and the Treatment of Diabetes Mellitus
Treating Diabetes Mellitus. There are two main types of diabetes. Type I diabetes
(previously called insulin-dependent diabetes mellitus, IDDM) is a severe form which
occurs most commonly in juveniles and young adults and which results from an absolute
insulin deficiency arising from pancreatic B cell destruction, presumably via an immune-
mediated mechanism. Type II diabetes (previously called non-insulin-dependent dia-
betes mellitus, NIDDM) is a milder, heterogeneous form of diabetes which occurs more
HORMONES AND THEIR RECEPTORS 369