Diabetes Demands a Triad of Treatments
Shot of Insulin
The first insulin for diabetes was derived from the pancreas of cows and pigs. Today, chemically synthesized human insulin is the most often used. It is prepared from bacteria with DNA technology. Human insulin is not necessarily an advantage over animal insulin, and most doctors don't recommend that patients on animal insulin automatically switch to human insulin. But if they do switch, dosages may change. Human insulin is preferred for those patients who take insulin intermittently.
According to Robert Misbin, M.D., medical officer for metabolic and endocrine drug products in FDA's Center for Drug Evaluation and Research and a practicing physician, some diabetics take beef insulin for religious reasons because of dietary restrictions against pork. "But the vast majority of insulin-dependent diabetics take synthesized human insulin," he says. "Those who are taking a beef or pork insulin and doing well -- you don't necessarily change the type of insulin they take. But for new patients I see, I would start them on human insulin."
Diabetics on intensified insulin therapy -- that is, those needing multiple daily injections or an insulin pump, which is worn 24 hours a day -- can have flexibility in when and what they eat. Other diabetics on insulin therapy must eat at consistent times, synchronized with the time-action of the insulin they use.
In 1996, FDA approved Humalog, which Misbin describes as "a modified human insulin." Humalog is absorbed and dissipated more rapidly than regular human insulin. Misbin says that Humalog is of particular benefit to Type I diabetics who are on very strict regimens.
Julio V. Santiago, M.D., director of the Diabetes Research and Training Center at Washington University's School of Medicine in St. Louis, notes that Humalog is most helpful for diabetics monitoring their blood sugar levels and taking three or more injections of insulin a day. He reports switching most of his Type I patients who fit that profile to the new insulin.
Four classes of oral diabetes drugs are now available. The oldest class, sulfonylureas (SFUs), act on the pancreatic tissue to produce insulin. The newest one is Glimepiride, approved by FDA in 1996.