There is no limit to insulin’s effectiveness — the dose can be raised to whatever dose is necessary to reduce blood sugar to the desired level. Most drugs have an upper limit dose where they won’t work any longer but for insulin there is no dose ceiling and that’s a real unique favorable quality.
Insulin works by causing sugar (glucose) that becomes available from the food we eat to be taken up by the muscles, the liver, and the fat cells. Also, insulin causes the fat from the food that we eat to be taken up by the fat tissue underneath our skin, and insulin will also cause the protein that we eat from food to be taken up by our muscles. However, just like any medication, insulin has some side effects.

Possible insulin side effects are:
• Weight gain
• Worsening of insulin resistance
• Possible artery disease
• Hypoglycemia (low blood sugar attack, see section titled Hypoglycemia for solutions)

Long-acting insulins such as Lantus, Humulin U and the most recent Levemir have the least potential to cause low blood sugar. All other insulin may have the potential to create this urgent and grave condition known as hypoglycemia or low blood sugar.

With regards to drug interactions with insulin some drugs may cause an increase in blood sugar when taken with insulin. Some of those drugs are diuretics such as HCTZ, drugs such as Prednisone, oral contraceptives, and beta blockers such as Atenolol, Metroprolol, and Toprol.


• “I am being prescribed insulin and it means that this is the beginning of the end.” Not true, because as mentioned before, starting on insulin is just another beginning.
• “My neighbor was using insulin, which caused his kidneys to quit working, and he’s on dialysis now because of it.” Not true. Insulin does not cause kidney failure, but it is a complication of uncontrolled diabetes.
• “As soon as they put my father on insulin, he had to have his right foot amputated.” Not true — again, leg and foot amputations are caused by neuropathy and injury that has not been properly treated in time.
• “I can eat whatever I want because insulin will take care of my diabetes.” Medications alone will not bring your diabetes under control. Only by coupling insulin with favorable lifestyle choices will you be able to bring your blood sugar and diabetes under control.

Pharmacist George Tohme is author of "Lifestyle Makeover for Diabetics and Pre-Diabetics."