NPH insulin

NPH insulin. It is an intermediate-acting insulin preparation used in the management of diabetes mellitus, primarily type 1 diabetes and sometimes type 2 diabetes. Its duration of action is longer than regular insulin but shorter than modern long-acting insulin analogs like insulin glargine. The formulation was a significant advancement in diabetes management, allowing for fewer daily injections compared to earlier regimens.

Medical uses

NPH insulin is prescribed to provide a baseline level of insulin activity, often covering insulin needs between meals and overnight. It is frequently used in combination with shorter-acting insulins, such as insulin lispro or insulin aspart, in regimens for type 1 diabetes. In type 2 diabetes, it may be added to oral medications like metformin or sulfonylurea when glycemic control is inadequate. Clinical guidelines from organizations like the American Diabetes Association have historically included it as a treatment option, though its use has declined with the advent of newer analogs. It is administered via subcutaneous injection, typically in the abdomen, thigh, or upper arm.

Adverse effects

The most common adverse effect is hypoglycemia, particularly during the peak action period several hours after injection. Weight gain is another frequently observed side effect. Injection site reactions, such as lipodystrophy or localized allergy, can occur but are less common. There is a risk of systemic allergic reaction, though this is rare. As with all exogenous insulin, improper dosing can lead to severe hypoglycemia, which may require intervention with glucagon or assistance from emergency services. Its peak action profile can contribute to nocturnal hypoglycemia, a significant concern in patient management.

Pharmacology

NPH insulin is a suspension of insulin complexed with protamine and zinc, which delays its absorption from the subcutaneous tissue. This protamine-insulin complex forms crystals that dissolve slowly, providing an extended duration of action. Its onset of action typically begins within one to two hours, peaks between four to ten hours, and can last up to eighteen hours. The pharmacokinetics can vary significantly between individuals based on factors like injection site and dose. It is metabolized by enzymatic degradation in the liver and kidney, similar to endogenous insulin.

History

NPH insulin was developed in the 1940s by researchers at the Nordisk Insulinlaboratorium in Denmark, founded by Hans Christian Hagedorn. The "NPH" name stands for Neutral Protamine Hagedorn, reflecting its neutral pH and the use of protamine discovered by Hagedorn. This development followed the earlier introduction of regular insulin by Frederick Banting and Charles Best. The creation of NPH insulin, along with Lente insulin, represented the first major step toward longer-acting insulin formulations, reducing the injection burden for patients. Its introduction was a landmark in diabetology, preceding later developments like those from Eli Lilly and Company and Novo Nordisk.

Society and culture

NPH insulin has been widely available for decades and is often considered a more affordable option compared to newer insulin analogs, impacting access in healthcare systems like the National Health Service and among patients in the United States. Its role has been discussed in controversies regarding insulin pricing. The drug is marketed under brand names such as Humulin N by Eli Lilly and Company and Novolin N by Novo Nordisk. It has been included on the World Health Organization Model List of Essential Medicines. Cultural references to its specific dosing and peak action are common in patient education materials from organizations like the Joslin Diabetes Center.

Category:Insulins Category:World Health Organization essential medicines