What is Insulin Lispro?
Insulin lispro is a fast-acting insulin analogue used for the treatment of diabetes mellitus. It was developed as an alternative to regular human insulin with a more rapid onset and shorter duration of action.

How Does it Work?
Insulin lispro has a slightly modified molecular structure compared to regular human insulin. It differs from human insulin by the reversal of the amino acids proline and lysine at positions B28 and B29 on the insulin molecule. This minor alteration allows insulin lispro to dissolve and take effect faster after injection under the skin compared to regular human insulin. It reaches peak levels within 5-15 minutes and continues working for 2-4 hours after injection. This modified time-action profile makes insulin lispro a good option for patients needing insulin coverage around mealtimes.

Approval and Marketing
Insulin lispro was first approved by the FDA in 1996 for use in diabetes. It was one of the earliest rapid-acting insulin analogues developed as an improvement over regular human insulin. Under the brand name Humalog, insulin lispro was quickly adopted as an attractive alternative for patients looking for faster relief of high blood sugars after meals. It is now commonly prescribed worldwide and remains one of the top selling insulin products.

Administration
Insulin lispro is generally administered via subcutaneous injection into the abdomen, upper arm, or thigh areas using a small insulin pen or syringe. It can be given immediately before, during or right after a meal and works quickly to counter rising blood sugar levels from ingested carbohydrates. The onset time allows more flexibility around meal timing compared to regular human insulin injections. Most patients find the subcutaneous delivery route straightforward to incorporate into daily life.

Clinical Evidence
Numerous clinical trials have demonstrated insulin lispro's advantages versus regular human insulin for postprandial glucose control in both type 1 and type 2 diabetes patients. One large meta-analysis published in 2002 reviewed over 20 studies and found insulin lispro provided statistically superior glycemic control as measured by reductions in post-meal blood glucose levels and hemoglobin A1c values over human insulin therapy alone. Fewer episodes of hypoglycemia were also observed with lispro compared to regular insulin in some study populations. Overall, insulin lispro offers modest but meaningful improvements in glycemic management for patients who require prandial insulin therapy.

Side Effects
The side effect profile of insulin lispro is generally similar to that of regular human insulin, with hypoglycemia being the most common adverse reaction. Reactions may occur if a dose is taken without eating, if more insulin is taken than required, or if exercise is not taken as expected after a dose. Other potential side effects include weight gain, skin reactions at the injection site, and lipodystrophy (softening or thickening of the skin). Close monitoring of blood sugars and proper precautions are necessary to avoid hypoglycemia risks.

Dosage Guidance
The dosage of insulin lispro must be individualized for each patient by their healthcare provider. Factors considered include a patient's type of diabetes, level of glycemic control needed, diet, exercise routine, other medications, and the presence of any kidney or liver disease. Most patients start on a dosage of 0.1-0.2 units per kg of body weight, with injections taken a few minutes before each main meal. Dosage adjustments are then based on blood sugar monitoring to fine tune control. Patients must be trained how to properly measure, draw up, inject and dispose of their insulin as prescribed.

Place in Therapy
As one of the earliest rapid-acting insulin analogues developed, insulin lispro remains an important treatment option, particularly for those needing help managing postprandial blood sugars. Its modified structure allows for flexible pre-meal timing that can aid lifestyle convenience compared to regular human insulin. Clinical trials support modest yet measurable improvements in glycemic control. Overall, insulin lispro provides a well-established fast-acting alternative for patients who require prandial insulin coverage as part of their diabetes management therapy plan.