Insulin and Hypoglycemics
INSULINS
DRUGS |
INFO |
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Insulin (general) |
Pre-pro insulin is cleaved (-NH3) in the ER — pro-insulin is cleaved in the golgi (C-peptide) — insulin (A & B chains).
Glucose is primary physiological stimuli for insulin secretion. ANS — islets are innervated by vagus — cholinergic stimulation will increase insulin secretion. Phase I of secretion — @ 15 minutes — type 2 diabetics have low or absent phase I secretion. Phase II of secretion — @ 40 minutes — proportional to glucose concentration — sulfonylurease sensitize b cells to phase II. When glucose enters pancreatic b cell — decrease in K+ flow — sulfonylureas also decrease the K+ flow. Ca ++ enters the cell — (+) effect on insulin release (Ca++-dependent). |
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Insulin Isophane (NPH) |
Intermediate onset of action. |
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Insulin Zinc (lente) |
Intermediate onset of action. |
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Ultralente Insulin |
Slow onset of action. |
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Humulin |
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Insulin Lispro |
HYPOGLYCEMICS
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DRUG |
MECH |
ADVERSE |
OTHER |
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SULFONYLUREAS 1st generation: Tolbutamide Chlorpropamide 2nd generation: Glipizide Glyburide |
Increases sensitivity of b-cells to glucose.
Inhibits the ATP-gated K+ channel on the b-cells. Increases insulin secretion. Increases binding of insulin to target tissues (minor action). |
Decreased I uptake in thyroid.
Disulfuram rxn with EtOH. Can be displaced from plasma proteins leading to hypoglycemia. Tolbutamide — increases CV deaths. Chlorpropamide — ADH-like effect. |
1st generation drugs have lower potency and greater side effects.
Pregnancy — teratogenic — cross placenta — deplete fetal insulin — tx with insulin. Only if weight reduction & diet are ineffective. |
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Metformin |
Decreased blood glucose levels — exact mechanism is unknown — might decrease liver gluconeogenesis.
Decreases LDL & VLDL and increases HDL. |
Less risk of hypoglycemia.
Lactic acidosis. decreased B12 absorption. |
Improves peripheral tissues’ sensitivity to insulin.
Biguanide. |
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Traglitazone |
Decreased plasma glucose, insulin, and TG. | Same as above.
Thiazolidinedione. |
Tags: C-peptide, Chlorpropamide, Glipizide, Glucose, Glyburide, Humulin, insulin, Insulin Isophane, Insulin Lispro, Insulin Zinc, metformin, pancreatic b cell, sulfonylureas, Tolbutamide, Traglitazone, Ultralente insulin
