It has been estimated that by 2025, 300 million people will have diabetes, a remarkable 5.4 percent of the world’s projected population. India is projected to have largest number of diabetics by 2025.

In normal healthy individuals, the body’s energy is met through burning of glucose within the cells. The pancreas hormone-insulin, controls the passage of glucose from blood to the cells. It is also required for conversion of glucose to glycogen in the liver and formation of fatty acids in the adipose cells. Thus, the lack of insulin causes an increase in blood sugar level causing hyperglycemia, a condition commonly called diabetes (diabetes mellitus).

It is basically of two types: Type I (insulin dependent) and Type - II (non insulin dependent).

Type I diabetes treatment requires use of insulin from external source while Type II can be treated with oral hypoglycemic agents and/or insulin from external source. Indeed, in Type - I diabetes, the patient’s survival depends on daily injections of insulin.

Insulin is a protein and would be digested before reaching the blood stream. Hence, it is not yet feasible to have oral form of insulin, either tablet, capsule or oral liquid. It is available as injection for subcutaneous administration. There are two types of insulin based on external source: animal source and human source (genetically engineered).

Though both have similar efficiency in controlling blood glucose level, human insulin is more tolerable. Animal insulin often has a risk of insulin allergy, but is cheaper. There are different types of insulin preparations available in the market. These include quick acting, short acting, intermediate acting, long acting and mixed.

As different types of insulin work at different speeds and for different duration, and patients respond differently to insulin, it is the doctor who decides the best insulin for his/her patient. Though injection is the most common form of insulin administration, currently other modes of delivery is also available like insulin inhaler, insulin pump, etc.

Regular monitoring of blood glucose is a must for the patient taking insulin. Easy-to-use glucometers are available. Once diet schedule and insulin dosage are adjusted, it should be followed meticulously. Otherwise, the blood-glucose maintenance is disturbed. The injection of insulin from this site becomes erratic and uncontrollable. The site of the injection must be rotated.

Like other medicines, insulin too has side effects. The most common is hypoglycemia (lowering of blood glucose level). Serious hypoglycemia may occur with over dosing, missing of meals, inappropriate exercise, vomiting and diarrhoea, and after drinking alcohol. The symptoms are headache, palpitations, sweating, tremor, nausea, blurred vision, increased hunger, speech and motor dysfunction etc.

If hypoglycemia is suspected, blood glucose should be tested immediately and sweets, sugar or glucose should be taken or given orally.