Inhaled insulin ("Exubera") was studied in 60 patients with diabetes in the USA who took one or two puffs of a powdered insulin preparation before meals for 12 weeks, in addition to a long-acting injected insulin preparation each evening. The dry-powder insulin was packaged in blister packs of 1 and 3 mg doses, equivalent to about 3 and 9 IU of subcutaneous insulin, respectively. The dose of insulin was individualized by a physician. Fifty-one of these patients chose to continue the inhaled insulin for a full year.

The overall diabetes control achieved with inhaled insulin was similar to the control with injected insulin. There were no reported lung problems or any increase in hypoglycemic reactions. Patient satisfaction was quite high. The study was reported in the June issue of Diabetes Care 27:1318-1323,2004.

This is an encouraging report. However, inhaled insulin is not yet commercially available or FDA-approved. Also, I've been concerned that inhaled insulin might act as a foreign protein in the lung and trigger asthma or other lung inflammatory conditions, particularly in patients who already have high serum titres of anti-insulin antibodies. Lung problems were not reported to be a problem in this one-year study, but patients with asthma were excluded. Another concern is the relative diffficulty (compared to injected insulin) of giving a precise dose of insulin. Also, using inhaled insulin does not eliminate the need to check a fingerstick blood glucose before each meal and at bedtime. The study was supported by pharmaceutical firms. Longer-term independent studies will be required to determine the safety and efficacy of chronic inhaled insulin.

In the meantime, insulin injections have become less painful with use of 31 guage "Shortee' needles. These are available in syringes that are 30U, 50U or 100U. I recommend using the 30-unit syringes if the insulin dose does not exceed that dose. Insulin injections are more convenient using insulin pens, which are available as either pre-filled or cartridge types. The BD Minipen and the NovoPen Jr are cartridge pens that can administer half-unit doses of lispro insulin, which is important for children and adults who are very sensitive to small doses of insulin. Air bubbles can get into insulin pens, so it is important to inspect the insulin prior to injection and inject out any air bubbles prior to insulin injection. Insulin comes out of the pens slowly, especially when the 31 guage needle is used, so it is advisable to keep the needle in the skin for several seconds to make sure all the insuln is injected.

I have been impressed with the effectiveness of the newer long-acting insulin: "insulin glargine" marketed as "Lantus". Lantus insulin has a longer duration of action than Lente or NPH insulins, meaning that most patients can take a single dose of Lantus in the evening; some patients, particularly those requiring small doses of Lantus, find that the evening dose of Lantus insulin does not provide suffficient 24-hour basal coverage and "split" the dose, taking half in the morning and half in the evening. Patients using Lantus insulin have 75% fewer nocturnal insulin reactions (compared with NPH insulin, that has a peak effect in the wee hours when it is taken at bedtime). Diabetic patients who use Lantus insulin are very sensitive to Humalog/Novolog insulin at bedtime; nocturnal hypoglycemia can result, so reduced doses (or no) Humalog/Novolog at bedtime are recommended. Patients with slowly-worsening Type 2 diabetes can take Lantus insulin as a supplement to their oral agents and avoid multiple pre-meal injections, at least for a time.

Some people with diabetes have high blood sugars in the morning before breakfast, but better blood sugar control during the rest of the day, even after meals. This is called the "dawn phenomenon" and is usually caused by an increased requirement for insulin in the early morning hours before awakening. It can also be caused by bedtime snacking, by inadequate insulin levels or by nocturnal insulin reactions that cause rebound hyperglycemia, the "Somogji reaction". The dawn phenomenonon and nocturnal hypoglycemia are quite common in patients using NPH or Lente as their bedtime insulin. Lantus insulin has reduced this problem. Nevertheless, some patients continue to have early morning hyperglycemia. Such patients may wish to try an insulin pump that can be programmed to autimatically deliver more basal-rate insulin in the hours before awakening.