18 Questions
How does insulin lispro differ from regular human insulin?
Insulin lispro has proline and lysine at positions β28 and β29, while regular human insulin has lysine and proline at those positions.
What is the function of the amino acid substitution in insulin aspart at position β28?
Facilitates absorption by preventing aggregation into hexamers and dimers.
Why is insulin glulisine considered suitable for IV use only in normal saline?
It needs the stabilizing effect of saline to prevent degradation.
Which insulin analog has a duration of action similar to regular crystalline insulin?
Insulin glulisine
What makes the three ultra-rapid acting insulins (lispro, aspart, glulisine) unique in terms of onset compared to regular crystalline insulin?
They dissociate faster into monomers leading to quicker absorption.
What distinguishes Humalog® (insulin lispro) from regular human insulin in terms of amino acid sequence?
Humalog® includes lysine and proline at β28 and β29, differing from regular insulin's positions of lysine and proline at those sites.
What is the primary similarity in the mechanism of action of nateglinide and repaglinide?
Both agents bind to and close ATP-dependent K+ channels in pancreatic cells
What is a key difference in the pharmacokinetics between nateglinide and repaglinide?
Nateglinide has a longer plasma half-life compared to repaglinide
Why are meglitinides like nateglinide and repaglinide administered shortly before a meal?
To reduce post-prandial glucose levels in diabetic patients
What is a common adverse effect associated with meglitinides like nateglinide and repaglinide?
GI upset and headache
In what way do nateglinide and repaglinide differ in terms of excretion?
Nateglinide undergoes renal excretion
Why is repaglinide contraindicated in patients taking gemfibrozil?
It interacts adversely with gemfibrozil, causing severe hypoglycemia
What modification is made to the alpha-chain of human insulin to create insulin glargine?
Replacement of arginine with glycine at position 21
Why does insulin glargine have a longer duration of action than NPH insulin?
It forms microprecipitates at the injection site
What is unique about the solution of insulin glargine?
It is a clear solution buffered at pH 4
What is the approximate onset of action of insulin glargine?
1.1 hours
Why is insulin glargine administered once a day?
Because it provides a peakless basal insulin level that lasts 24 hours
What is important to note when mixing insulins with insulin glargine?
It should not be mixed with any other insulin
Learn about the bioengineering details of insulin glargine (Lantus), a long-acting preparation with specific modifications. Understand the changes in isoelectric point, solubility properties, and the addition of arginines in this bioengineered insulin.
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