Chapter 13: Diabetes Flashcards
Type 1 DM
2-5% of all cases
induced by auto-immune destruction of pacnreatic cells
Type 2 DM
90-95% of cases
prevalence varies by ethnicity
strong genetic predisposistion
plasma insulin levels drop as the body develops resistance
oral hypoglycemics
sulfonylureas
biquanides
alpha-glucosidase inhibitors
thiazolidines
meglitinides
DPP-4 inhibitors
glucosuria
glucose in urine d/t kidney excreting too much
polyuria
increased urination
polyphasia
increased appetitie
polydipsia
increased thirst
poor glycemic control places at a high risk for
retinopathy
neuropathy
MI
what is treatment for T2DM based on
HGBA1C results
what medications are obese patients more likely to benefit from and why
metformin because it acts more on glucose utilization and hepatic glucose storage and production
which medication do non-obese diabetic patients respond better to
sulfonylureas
patients who are at risk for hypoglycemia benefit more from which drug and why
metformin because it is less likely to produce it
what do patients with a high postprsndial glucose level beneit most from
addition of a glucosidase inhibitor or a meglinitidine
steps for treatment of T2DM
- lifestyle intervention and metformin (titrated to maximum effective dose over 1-2 months)
- additional medications
- glycemic control (start insulin)
sulfonylureas
mechanism of action
- lowers blood glucose by increasing insulin secretion from pancreatic Bcell
- decreases glycogenolysis
- decreases glyconeogenesis
- increase cell sensitivity to insulin
sulfonylureas clinical uses
monotherapy an in combination with other drug classes as well as insulin
sulfonylureas should not be used in combination with what
meglitinides
why is there controversy ove whether sulfonylureas should be as first line therapy for T2DM
only lowers A1C levels by 1-2%
1st class of drugs used to treat T2DM
conscientious prescribing of sulfonylureas
start low, go slow, watch for toxicity
mild-mod T2DM responds best
combination therapy is popular
the only sulfonylureas that doe not cause weight gain
metformin
patient education for sulfonylureas
take 30-40 minutes before eating and never on an empty stomach
watch for weight gain, GI upset, gas
avoid alcohol and ASA
accu-checks
what medications increase the effects of sulfonylureas
CYP450 inhibitors
(azoles, NSAIDs, sulfonamides, antidepressants, MAOIs, and digitalis)
what medications may decrease the effects of sulfonylureas
CYP450 inducers
(phenobarbital, beta blockers, and hydantoins)
sulfonylureas contraindications
cross-sensitivy to sulfonamides (including thiazide diuretics)
severe renal, hepatic, thyroid, or other endocrine disorders
uncontrolled infection, burns, and trauma
biguanides: Metformin (Glucophage)
first line therapy
lowers A1C 1-2%
metformin mechanism of action
reduces hepatic production of glucose and inhibits intestinal absorption of glucose
metformin clinical uses
monotherapy and in combination with other agents
conscientious considerations for metformin
- decreases LDL, trigs, plasminogen, B12
- combinations are more effective than monotherapy
- monitor renal function for ketoacidosis
- dc if hypoxic or surgery
- assess for HF, septicemia metabolic acidosis, pregnancy
- many drug interactions
patient education for metformin
take missed dose within an hour of scheduled dose or waite until next scheduled dose
healthy diet, avoid alcohol
regular follow-up is necessary
test for blood glucose and urine ketones
what medications may increase metformin levels
lasix, nifedipine, cimetidine, cationic drugs (digoxin, amiloride, procainamide, quinidine, ranitidine, trimethoprim, vancomycin, triamterene, morphine)
what medications increase hyperglycemia risk when taken with metformin
thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, CCBs, and isoniazid
what can cause hypoglycemia when taken with metformin
alcohol
excess alcohol can increase risk for lactic acidosis
metformin contraindications
those at increased risk for lactic acidosis d/t renal impairment
hepatic dysfunction, HF, metabolic acidosis, dehydration, alcoholism
Meglitinides: secretagogues
mechanism of action
close ATP-dependent potassium channels in the beta cell membrane by binding at specific receptor sites causing insulin release
lowers A1C by 0.6-1%
examples of meglitinides
repaglinide (Prandin)
nateglinide (Starlix)
why must meglitinides be adminstered more often than sulfonylureas
they have a shorter half-life
meglitinides clinical usage
postprandial hyperglycemia
which meglitinide is almost as effective as metformin
repaglinide
meglitinide dosages are based on
A1C levels
meglitinide therapy
monotherapy has better long term effects
may need adjunct insulin in times of stress
what medications may lead to increased serum concentrations of meglitinides resulting in hypoglycemia
gemfibrozil, macrolide antibiotics, many herbals (St. John’s wort, ethanol, garlic), any drug affected by the CYP450 system
meglitinides contraindications
hepatic impairment
meglitinide patient education
take with meals 2-4 times a day
watch for weight gain and hypoglycemia
thiazolidinediones (TZDs) mechanism of action
increase sensitivity of muscle, fat, and liver to endogenous and exogenous insulin
improves cellular response to insulin without increasing output of insulin from the pancreas
benefits of TZDs
do not produce hypoglycemia in diabetic or nondiabetic patients
most common adverse effects of TZDs
weight gain, fluid retention
clinical use of TZD
indicated as monotherapy and in combination with metformin, sulfonylureas, and insulin