Diabetes: Insulin Replacement, Oral Medications, Organ Transplants

by Food and Drug Administration (FDA)

(Page 3 of 4)

Insulin Replacement Therapy

Before the availability of insulin, treatments for people with type 1 diabetes were unpleasant and often ineffective. A low-carbohydrate, semi-starvation diet and exercise were all doctors had to offer. People lost more and more weight, and many of them died within the first year of diagnosis. Like many scientific advances, the discovery of replacement insulin in the 1920s was nothing short of a miracle.

Insulin lowers blood sugar by both increasing the removal of glucose from the blood and reducing the production of glucose by the liver. In type 1 diabetes, since there is virtually no insulin produced by the pancreas, people need insulin all the time — more at mealtimes to "cover" the carbohydrates and protein eaten, and less during other times to maintain as even a level as possible. In people with type 2 diabetes, insulin injections sometimes are needed to supplement the amount produced by the pancreas.

Insulin injections are given under the skin (subcutaneously) into the fat layer, usually in the arm, thigh, or abdomen. Insulin cannot be given by mouth because it is destroyed by digestive enzymes in the stomach. Small syringes with very thin needles make the injections nearly painless. In recent years, several external insulin pumps, which deliver insulin continuously through a thin, flexible tube placed under the skin, have been developed.

There are more than 20 types of insulin available in four basic forms, each with a different time of onset and duration of action (see "Insulin Preparations."). The decision as to which insulin to choose is based on an individual's lifestyle, a physician's preference and experience, and the person's blood sugar levels. Among the criteria considered in choosing insulin are: how soon it starts working (onset), when it works the hardest (peak time), and how long it lasts in the body (duration).

Oral Medications

Pills to treat diabetes — antidiabetic agents — are used only in type 2 treatment. Four general classes of drugs work in different ways to lower blood sugar (see "Oral Antidiabetes Medications."). There are some risks associated with the use of these drugs. For example, sulfonylureas, which stimulate the beta cells in the pancreas to release more insulin, can be associated with severe low blood sugar levels, particularly when the person has other medical problems or is taking other medications. And in order for them to work, a person's pancreas must be making at least some insulin. That is why oral medications will not work for the treatment of type 1 diabetes.

For best results, oral medications must be taken regularly every day, not irregularly or started and stopped according to blood sugar. Since many dosages are available, a physician can change the dosage if blood sugars are running too high or too low. Many of these drugs can be used in combination with one another, but any change in their use should be done only at the direction of a health-care professional.

Driscoll's doctor found that oral medications were not effective in controlling his blood sugar, and he replaced them with insulin injections. In retrospect, Driscoll says, "while the pills were easier to deal with, insulin has made the greatest difference in my life." In addition, Driscoll has shed 40 of the 100 pounds recommended by his doctor as part of his treatment plan.

Organ Transplants

Pancreas transplants and kidney transplants are options for people with type 1 diabetes, if they have kidney failure (about one-third of type 1 patients). Since the 1970s, doctors have performed pancreas transplants along with kidney transplants in hopes of halting or reversing the complications of diabetes. The procedure has met with some success. Kidneys alone are transplanted to replace kidneys that have totally failed. Pancreas transplants may be done simultaneously or after kidney transplants, to try to "cure" diabetes. But pancreases are often not transplanted unless a kidney is also needed, says Saudek, "because the surgery is so major and the need for continuous immune suppression is more dangerous than taking insulin." Saudek adds that unavailability of transplantable kidneys and pancreases also is a factor.

A kidney transplant for people with type 1 and type 2 diabetes can restore the body's ability to perform a number of crucial functions, including filtering wastes from the blood and controlling the body's fluid and chemical balance. Receiving a new pancreas at the same time may actually improve kidney survival. In addition, a new pancreas can improve blood sugar levels to normal, or close to it.

Organ transplants aren't always successful. Besides the risk inherent in any major surgery, the body can reject the new organ days or even years after the transplant. Because of this, transplant recipients will likely need to take immunosuppressive drugs the rest of their lives. The drugs themselves carry significant health risks, such as cancer, but they work to prevent the immune system from rejecting the new organ.

Another noteworthy therapeutic intervention, and one that Keister hopes to be considered for, is a procedure called islet cell transplantation. Researchers have known for some time that transplanting these insulin-producing cells may provide a possible cure for type 1 diabetes. The process to date is still not perfected, but there is some evidence that researchers may be getting closer to their goal.

About the Author

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