Insulin Administration Methods Quiz

Insulin Administration and Pharmacokinetics

• Intermittent subcutaneous (SC) injections should be administered approximately 15-30 minutes before a meal.
• The onset of action for regular insulin following an SC injection is about 30 minutes.
• The duration of action for regular insulin lasts approximately 6 to 8 hours.
• Neutral Protamine Hagedorn (NPH) insulin is not suitable for intravenous (IV) use due to its prolonged duration and potential for unpredictable absorption.
• Regular insulin is typically used intravenously in critical situations like diabetic ketoacidosis or during surgeries when tight glycemic control is required.

Metformin and Its Mechanisms

• Metformin is primarily known for its ability to lower blood glucose levels in type 2 diabetes.
• It is absorbed into hepatocytes through facilitated diffusion, mainly using the organic cation transporters.
• A common misconception is that metformin is less effective than sulfonylureas in lowering blood sugar when, in fact, it has distinct advantages, including a lower risk of hypoglycemia.
• The mechanism by which metformin lowers hepatic glucose production is through the activation of AMP-activated protein kinase (AMPK).
• Metformin is classified as an antihyperglycemic agent; it works against elevated blood glucose levels.
• The primary target organ for metformin's glucose-lowering effects is the liver.

Insulin Delivery Systems

• Continuous subcutaneous insulin pumps aim to provide a steady delivery of insulin, improving overall glycemic control.
• Portable pen-sized injectors offer advantages in convenience, precision, and dosing flexibility for insulin administration.
• A notable side effect associated with the rapid-acting inhaled formulation of insulin (Afrezza®) is potential lung-related adverse effects, including cough and reduced lung function.
• Standard therapy for insulin treatment typically involves fewer injections and less intensive monitoring, contrasting with intensive treatment protocols requiring more frequent dosing and checks.

Considerations for Inhaled Insulin

• The inhaled formulation of insulin is contraindicated in patients with any lung disease due to risks of respiratory complications.
• Afrezza® provides rapid mealtime insulin coverage, mimicking physiological insulin release and effectively addressing postprandial glucose spikes.
• Increased AMP levels contribute to a reduction in glucose production, promoting better glycemic control when AMPK is activated.

Metformin Metabolism and Risks

• Metformin is eliminated primarily through the kidneys.
• In patients with kidney disease, a reduced glomerular filtration rate (GFR) suggests an increased risk of lactic acidosis, a potentially serious side effect of metformin.

Thiazolidinediones (TZDs) Impact

• Adenosine Monophosphate-Activated Protein Kinase (AMPK) plays a critical role in reducing hepatic glucose production through modulation of metabolic pathways.
• Thiazolidinediones (TZDs) mediate effects on gene expression, enhancing insulin sensitivity and improving lipid metabolism.
• The GLUT-4 transporter facilitates glucose uptake in muscle and fat tissues, playing a key role in overall glucose homeostasis.
• Enzymes not included as expressed by TZDs include those related to gluconeogenesis inhibition.
• Troglitazone (Rezulin®) was removed from the market due to severe liver toxicity and associated complications.
• Regular liver function tests are recommended every 3 to 6 months for patients treated with TZD agents to monitor for potential hepatotoxicity.
• Rosiglitazone (Avandia®) and pioglitazone (Actos®) have been emphasized for their efficacy in improving insulin sensitivity, with caution against cardiovascular risks associated with their use.