Nausea, tremors, empty-headedness, unexplained hunger, blackout… With more and more diabetics suffering attacks of hypoglycaemia following a changeover from animal to human insulin, diabetologists in the city have expressed concern over the “casual, unsupervised switch” which, they maintain, is more often than not the culprit.
More than 10 per cent of Calcutta’s adult population has diabetes, and a large section of these diabetics are dependent on insulin. The New Year had brought cheer to diabetic patients, with the price of human insulin being slashed drastically. One phial of human insulin now costs Rs 145, down from the previous tag of Rs 218, bringing it on a par with the prevailing prices of porcine insulin.
While hailing this price relief and the “absolute purity” of human insulin, doctors feel the switch should be effected under strict medical supervision, with close monitoring, to avert hypoglycaemia — a condition in which the blood glucose level drops to a dangerous low. It can lead to coma, and even death, if not addressed immediately.
The molecular structure of animal insulin is different from insulin produced in the human body. Thus, beef or porcine insulin, when injected, is recognised by the body as foreign protein, eliciting an antibody response. These antibodies try to destroy the animal insulin in the patient’s body as a defence mechanism. “When the patient is injected with insulin again, part of that insulin will be bound by the antibodies already present. Consequently, the efficacy of the insulin will be less, which can be overcome by increasing the dose,” observes Subhankar Chowdhury, consultant and head, department of endocrinology at SSKM Hospital.
Most people switching from animal to human insulin are doing so on their own, or on advice of the chemist, without making the necessary adjustment to the dose. “This makes them more susceptible to hypoglycaemia. Ideally, the first two weeks of initiation should be supervised by a diabetologist, and during this period, a close watch kept on the blood glucose levels,” says Chowdhury, also honorary secretary of the Diabetic Association of India’s (DAI) city branch.
As the stimulus for antibody production is removed with human insulin, made in laboratories in a “sophisticated process” of recombinant DNA engineering, antibody levels come down in a couple of weeks, and the patient’s blood glucose level settles down. “The initial couple of weeks is usually the high-risk window,” warns Chowdhury, who has treated a significant number of hypoglycaemic shock cases in patients switching insulin forms.