Blood glucose

Question 1

Regular Insulin

Answer 1

Short acting

Uses;
-pre-meal glucose management 
-acute hyperglycemia 
-IV infusion during surgery
Tx of hyperkalemia 

MOA;

• structurally identical to endogenous insulin but zinc ion added for stability
• binds to plasma membrane receptors and tyrosine molecules are auto-phosphorlyated –> tyrosine kinase activity in the receptors –> phosphorylated intracellular insulin receptors can now translocated the glucose transporter (Glut-4) the cell membrane
  1. facilitate glucose diffusion into cell
  2. activate glycogen synthetase to store intracellular glucose as glycogen
  3. take up amino acids, K, Mg, phos
  4. stimulate protein synthesis and prevent proteolysis
  5. regulate gene expression in target DNA molecules

Dose; 1 unit expect a 30 - 50 mg/dL decrease in glucose

infusion; 0.05 - 0.1 units/kg/hr check glucose q 30 min
(**tight control glucose;
Insulin infusion rate (units/hr) = last plasma glucose ÷ 150 = rate concentration 100 units/ mL unless obese, infection or on corticosteroids use 100 [[CB]])

tx. hyper K; 10 units of insulin IV w/25 g of glucose over 5 min

[[once insulin saturated all binding sites it will NOT have a more potent effect, butt will last longer and have a greater net effect than smaller doses]]

Pharmacokinetics;
IV; rapid 
onset; 
E1/2t; 5 - 10 min 
DOA; 30 - 60 min 

SQ
onset; 30 - 60 min
Peak; 1 - 5 hrs
DOA; 5 - 8 hrs (up to 10)

insulin circulates unbound

metabolized by proteolytic enzymes in the liver and kidneys (almost all tissue in the body can metabolize insulin)

Very little excreted unchanged in the urine

Side Effects;

• hypoglycemia**
• allergic rxn (less common now)
• lipodystrophy (atrophy of fat at the SQ injection site) **rotate sites
• insulin resistance (>100u of exogenous insulin daily)

Caution
-liver and kidney dysfunction; increased risk of hypoglycemia (prolonged effects; decreased metabolism) (more profound with renal disease compared to liver)

interactions;
*ACTH *estrogen *glucagon
*Epi (blocks insulin secretion and stim glycogenolysis (break dow go glucagon to release glucose)
^antagonizes the effects of insulin trying to decreases glucose

*Abx, *salicylates (ASA), *phenylbutazone (NSAID)
^prolong DOA of insulin

*MAOi potentiate insulin effects –> hypoglycemia

Question 2

glucagon

Answer 2

-synthetic version of endogenous hormone produced by the pancreatic alpha cells

Uses;

• treatment of hypoglycemia
• acute cardiac failure from BB OD
• relaxes duodenal and choledochal for surgery
• tx sphincter of odd spasm r/t opioid
• differential dx of pheochromocytoma

MOA;

• endogenous hormone produced. by alpha cells of pancreas; stimulates cAMP and increases blood glucose by hepatic glycogenolysis and gluconeogenesis during hypoglycemia
• induced relapse of catecholamines that cause direct inotropic and chronotropic effects (increased HR and SV)

Dose;
CV; 1 - 5 mg IV then 20 mg/hr (5mcg/kg/min)
hypoglycemia; 0.5 - 1 mg
Sphincter of odd Spasm; 0.3 mg

Pharmacokinetics;

• peak; 5 - 20 min
• E1/2t; 3 - 6 min
• DOA: 60- 90 min

enzymatic degradation by liver, kidney and cell membrane receptor sites

Side Effects;

• N/V***
• hyperglycemia
• hypoglycemia (paradoxical effect is someone doesn’t have enough glycogen stores)
• hypokalemia
• Tachycardia
• MAP may increase

Contraindicated;
- hypersensitivity

Caution
-CAD? r/t increased HR

*monitor BP and HR