antidiabetics 59/60 Flashcards
Regular insulin (Humulin R and Novolin R)
Rapid-acting Insulin Preparation (cheap)
clear solution of human sequence insulin
only insulin suitable for intravenous use
works slower than native insulin due to regular insulins forming non-covalent hexamers in solution
breakdown into monomers requires time
Insulin aspart (NovoLog)
Rapid-acting Insulin Preparation
B28 proline is replaced by an aspartic acid residue
works quicker than regular insulin due to forming monomers more quickly
Insulin glulisine (Apidra)
Rapid-acting Insulin Preparation
B3 asparagine is replaced by a lysine residue and the
B29 lysine is replaced by a glutamic acid residue
(“glu and lis” replace)
works quicker than regular insulin due to forming monomers more quickly
Insulin lispro (Humalog)
Rapid-acting Insulin Preparation
normal proline-lysine (“lis for pro”) dipeptide at positions B28 and
B29 are reversed
works quicker than regular insulin due to forming monomers more quickly
NPH Insulin (Humulin N and Novolin N)
Intermediate-acting Insulin Preparation (cheap)
cloudy suspension of human sequence
insulin aggregated with protamine and zinc
unpredictable action due to a variable rate of absorption (still has peak)
mixture of NPH and regular insulin (or other short-acting) in a fixed proportion (70:30) often used
Insulin glargine (Lantus)
Long-acting Insulin Preparation: reproducible and convenient
background insulin replacement (last about 18-20 hours)
aspargine at position A21 is replaced by
glycine and two arginines are added to the C-terminus of the B-chain
soluble at pH 4 but poorly soluble at pH 7
injected subQ, forms fine precipitant in interstitial fluids
Insulin detemir (Levemir)
Long-acting Insulin Preparation: reproducible and convenient
background insulin replacement
threonine at B30 is omitted and a C14 fatty acid chain is attached to amino acid B29
long-acting due to self-association at subQ injection site and by binding to albumin in blood
Metformin (Glucophage, Glucophage XR, Glumetza)
Biguanide
first line for T2 DM
reduces of hepatic gluconeogenesis
through activation of the AMP-activated protein kinase (AMPK) in hepatocytes
euglycemic: prevents hyperglycemia, but does not induce hypoglycemia
Glyburide (Diaβeta, Micronase, Glynase PresTab)
Sulfonylurea
2nd generation
Repaglinide (Prandin)
Meglitinide
hypoglycemia w. skipped meal
Pioglitazone (Actos)
Thiazolidinedione
Rosiglitazone (Avandia)
Thiazolidinedione
Acarbose (Precose)
α-Glucosidase Inhibitor
Pramlitide (symlin)
Amylin Analogue
used for the treatment of type 1 and type 2 diabetes. It primarily acts as an insulin sparing agent, adjunct to insulin therapy
Exenatide (Byetta)
GLP-1 Agonist
synthetic exendin-4, a peptide found in Gila monster venom
monotherapy or as adjunctive therapy for T2 DM, 2x daily, subQ
now extended release 1x weekly
rapidly absorbed from the injection site and reaches a pk conc. in 2 hrs
little metab, excreted by kidney
Sitagliptin (Januvia)
DPP-4 Inhibitor
T2DM
Canagliflozin (Invokana)
SGLT2 inhibitor
Glucagon
29 aa peptide synthesized by the alpha cells in pancreatic islets of Langerhans
used in the emergency treatment of severe hypoglycemia, unconscious pt or glucose not available
also, tx of β–blocker OD
raises blood glucose by stimulating the breakdown of hepatic glycogen stores
binds to a G-protein coupled receptor present in the liver that stimulates adenylate cyclase and an increase in cAMP–>increase in glycogen phosphorylase activity and a decrease in glycogen synthase activity
stimulates gluconeogenesis and ketogenesis in the liver
no effect on glycogen stores in skeletal muscle.
metabolized by liver, kidney and within plasma
Glucose stimulation of insulin
secretion involves the uptake of glucose into the β cell via ??
GLUT-2
transporters
intracellular metabolism of glucose increases the ATP/ADP ratio, which inhibits K(ATP) channels and potassium efflux This inhibition results in ??
Calcium influx does what??
β cell
depolarization and calcium influx
activates recruitment of insulin- containing granules to the cell surface and the release of insulin into the circulation
average individual produces ?? insulin/day
30 units
- half metabolized by liver
- rest by kidney and muscle
insulin is produced as a ??
prepropeptide, starts in RER–>folding, disulfide bonds added–>proinsulin goes to golgi–>packaged in granules (immature)–>proinsulin matured here–>cleaved to insulin and C-peptide (inactive compound)–>granules (in pancreatic B-cells) fuse with plasma membrane and release mature insulin into blood
always basal insulin in circulation
large insulin release after glucose spike in blood
if given bolus of glucose…normal pt would respond with ??
insulin spike from release of pre-formed insulin from B-cells, then depletes
second (more subtle) hump from release of newly created insulin
if given bolus of glucose…Type 2 diabetic pt would respond with ??
delayed and more subtle insulin hump (no spike)
if given bolus of glucose…Type 1 diabetic would respond with ??
no response, unable to produce insulin
insulin has 2 effects ????
that affects what tissues ??
anabolic and anticatabolic
liver, muscle, and
adipose tissue
insulin anticatabolic effects in liver ??
anabolic effects in liver ??
inhibits glycogenolysis, gluconeogenesis, ketogenesis
stimulates glycogen and fatty acid synthesis
insulin anticatabolic effects in muscle ??
anabolic effects in muscle ??
inhibits protein catabolism
stimulates glucose and amino acid uptake
stimulates protein and glycogen synthesis
insulin in adipose tissue:
anticatabolic effects ??
anabolic effects ??
inhibits lipolysis
stimulates glucose uptake
stimulates glycerol synthesis and triglyceride synthesis
“dawn phenomenon” in DM pts
glucose is fine before bed, high in morning
insulin wore off, not enough to inhibit gluconeogenesis in liver
history factoid: started using insulin in humans in ??
1922
before: 0% survival rate
Fredrick Banting “discovered” insulin and began testing injections
initially bovine/porcine
now human via recombinant DNA technology (cleaner prep and less hypersensitivity) since 1982
Type 1 diabetes mellitus
absolute deficiency in insulin due to the
autoimmune destruction of pancreatic β cells
untreated–>ketoacidosis–>coma–>death
insulin replacement therapy is necessary to sustain life
younger than 30 years old when diagnosed
Type 2 diabetes mellitus
90-95% of all diagnosed DM in US
initial development of insulin resistance, followed
by a relative impairment of insulin secretion
Insulin is still produced by β cells in these patients but is not sufficient to overcome the resistance
present in adulthood
dietary intervention is first tx, then oral antiDM drugs
30% benefit from insulin therapy
may need higher units: 40-300 units/day: metabolic syndrome
insulin regimen: give multiple shots combo shots of ???
intermediate-acting (or long-acting): to mimic 24-hour basal insulin secretion
AND
short-acting insulin: to mimic nutrient-stimulated insulin secretion (given preprandial)