Diabetes Pt 2 - Rx's Flashcards
Exogenous (injected) Insulin
- Insulin from an outside source
- Req’d for type 1 DM
- Prescribed for pts w/type 2 DM who cannot control blood glucose by other means
- B/c type 2 DM is a progressive dz, over time the combo of nutritional therapy, exercise, & OAs may no longer adequately control BG lvls. At that point, exogenous insulin would be added as a permanent part of the management plan
- May also need up to 4 injections/day to adequately control their BG lvls
> may use an insulin pump
Human insulin
- Genetically engineered in labs
> Derived from common bacteria (e.g., Escherichia coli) or yeast cells through recombinant DNA technology
Categorized according to onset, peak action, & duration
- Rapid-acting
- Short-acting
- Intermediate-acting
- Long-acting
- The base of all insulin preparations is regular insulin; onset of activity, peak, & duration times are manipulated by adding zinc, acetate buffers, & protamine
- Zinc & protamine added to make intermediate-acting NPH (Neutral Protamine Hagedorn) can cause an allergic reaction @ the injection site in susceptible individuals
Insulin Regimens
Basal-bolus regimen
- Most closely mimics endogenous insulin production
- Rapid- or short-acting (bolus) insulin before meals
- Intermediate- or -long-acting (basal) background insulin once or twice a day
- Goal: to achieve a near-normal glucose lvl of 70-130 mg/dL before meals
- Less intense regimens can also be used
- Selection criteria based on the desired & feasible lvls of glycemic control & the pt’s lifestyle, diet, & activity patterns
- A more intense approach can be encouraged by the HCP when a less intense regimen isn’t giving pt optimal control
Mealtime Insulin (Bolus) - Insulin preparations
Rapid-acting (bolus)
- Lispro (Humalog), aspart (NovoLog), glulisine (Apidra)
- Onset of action 15 min
- Injected within 15 min of mealtime
- Most closely mimic natural insulin secretion in response to a meal
Short-acting (bolus)
- Regular w/onset of action 30-60 min
- Injected 30-45 minutes before meal
- Onset of action 30-60 min
! Is more likely to cause hypoglycemia b/c of longer duration of action
(Basal) Background Insulin
- Used to control glucose lvls in between meals & overnight
Long-acting (basal)
- insulin glargine (Lantus) & detemir (Levemir)
- released steadily & continuously w/no peak action
- administered once or twice a day
- do not mix w/any other insulin or solution in same syringe
- b/c they lack peak action time, risk for hypoglycemia is greatly reduced
- Along w/mealtime insulin, type 1 DM’s must also use a long-acting basal or intermediate-acting (background) insulin to control BG in-between meals & overnight
! W/o 24-hr background insulin = type 1 DM’s more prone to DKA
(Basal) Background Insulin
Intermediate-acting insulin
?
- duration 10-24+ hrs
- peak 4-12 hrs (can result in hypoglycemia)
- can mix w/short- and rapid-acting insulins
- cloudy; must agitate to mix
NPH
Combination Insulin Therapy
- Can mix short- or rapid-acting insulin w/intermediate-acting insulin in same syringe
- Provides mealtime & basal coverage in 1 injection
- Commercially pre-mixed or self-mix
Mixing Insulins
Insulin
Storage of insulin
- Do not heat/freeze
- In-use vials may be left at room temp up to 4 wks
- Extra insulin should be refrigerated
- Avoid exposure to direct sunlight, extreme heat or cold
- Store prefilled syringes upright for 1 week if 2 insulin types; 30 days for one
Administration of insulin
- Typically given by SC inj
- Regular insulin may be given IV
- Cannot be taken orally b/c inactivated by gastric juices
- Absorption is fastest from abdomen, followed by arm, thigh, & buttock
- Abdomen is preferred site
- Do not inject in site to be exercised
- Rotate injections within one particular site
- Usually available as U100 insulin (1 mL contains 100 U of insulin)
- U100 insulin must be used w/a U100-marked syringe
- Syringes marked for units: various sizes
- Only user recaps syringe
- No alcohol swab for self-injection; wash with soap & water
- Inject at 45- to 90-degree angle
Insulin pump
- Continuous SC infusion
- Battery-operated device
- Connected to a catheter inserted into SC tissue in abd wall
- Program basal & bolus doses that can vary throughout the day
- Potential for tight glucose control
- All insulin pumps are programmed to deliver a continuous infusion of rapid-acting insulin 24 hrs a day, known as the “basal rate”
- Basal insulin can be temporarily inc or dec on the basis of carb intake, activity changes, or illness; diff basal rates at diff times of the day may be needed
- Check BG lvl @ least 4x/day
- Allows for tight glucose control
! infection @ the insertion site; inc risk for DKA if insulin infusion is disrupted by a problem @ the infusion site; inc cost of pump & supplies
Problems w/insulin therapy
→ Hypoglycemia
→ Allergic reaction
→ Lipodystrophy (atrophy of SC tissue)
→ Somogyi effect
?
Morning hyperglycemia present on awakening
D/t release of counter-regulatory hormones in pre- hrs
Dawn phenomenon
Dawn phenomenon
- Characterized by hyperglycemia that’s present on awakening
- Been suggested that 2 counter-regulatory hormones, growth hormone & cortisol, excreted in increased amts in early AM hrs are responsible
- Affects a majority of people w/diabetes & tends to be most severe when growth hormone is at its peak in adolescence & young adulthood
?
Rebound effect in which an overdose of insulin causes hypoglycemia
Release of counter-regulatory hormones causes rebound hyperglycemia
Somogyi effect
Somogyi effect
- Hyperglycemia in the AM may be d/t the Somogyi effect
- A high dose of insulin produces a decline in BG lvls during the night
- As a result, counter-regulatory hormones (e.g., glucagon, epinephrine, growth hormone, cortisol) are released, stimulating lipolysis, gluconeogenesis, & glycogenolysis, which in turn produce rebound hyperglycemia
- Danger of this effect is that when BG lvls are measured in the AM, hyperglycemia is apparent, & the pt (or HCP) may increase the insulin dose
- If pt is experiencing AM hyperglycemia, checking BG lvls between 0200 and 0400 for hypoglycemia will help determine if the cause is the Somogyi effect
- Pt may report HA’s on awakening & may recall having night sweats or nightmares
- A bedtime snack, reduction in insulin, or both can help prevent the Somogyi effect
The treatment for Dawn phenomenon is ____
an increase in insulin or an adjustment in admin time
The treatment for Somogyi effect is ____
less insulin
- Ask the pt to measure & document bedtime, nighttime (0200-0400), & AM fasting BG lvls on several occasions
- If the predawn lvls are <60 mg/dL & s/s of hypoglycemia are present, the insulin dosage should be reduced
- If the 0200 to 0400 BG lvl is high, the insulin dosage should be inc; in add’n, counsel pt on appropriate bedtime snacks
Oral Agents
Work on 3 defects of type 2 DM
- insulin resistance
- decreased insulin production
- increased hepatic glucose production
- These drugs may be used in combination w/agents from other classes or w/insulin to achieve BG goals
Biguanides
> Metformin (Glucophage)
* Reduces glucose production by liver
* Enhances insulin sensitivity @ tissue lvl
* Improves glucose transport into the cells
* May cause wt loss
* Used in prevention of type 2 DM
! Withhold if contrast medium is used
- Withhold if pt is undergoing surgery or radiologic procedure w/contrast medium
- day or two before & @ least 48 hrs after
- monitor serum creatinine
! Contraindications !
- renal, liver, cardiac dz
* lactic acidosis is a rare complication of metformin accumulation
- excessive alcohol intake
?
↑ insulin production from pancreas
Major s/e: hypoglycemia
e.g.,
- Glipizide (Glucotrol)
- Glyburide (Micronase, DiaBeta, Glynase)
- Glimeperide (Amaryl)
Sulfonylureas
?
↑ insulin production from pancreas
Rapid onset: ↓ dec chance of hypoglycemia
Taken 30 min to just before each meal
Should not be taken if meal skipped
e.g.,
- Repaglinide (Prandin)
- Nateglinide (Starlix)
Meglitinides
?
“starch blockers”
- slow down absorption of carbohydrate in small intestine
- take w/first bite of each meal; most effective in lowering postprandial BG
e.g.,
- Acarbose (Precose)
- Miglitol (Glyset)
α-Glucosidase Inhibitors
?
Most effective in those w/insulin resistance
- Improve insulin sensitivity, transport, & utilization @ target tissues
e.g.,
- Pioglitazone (Actos) [! can worsen HF & assoc w/inc risk bladder ca]
- Rosiglitazone (Avandia) [! MI]
- rarely used b/c of adverse effects
Thiazolidinediones
Dipeptidyl Peptidase-4 (DPP-4) Inhibitor
- Blocks inactivation of incretin hormones
↑ insulin resistance
↓ glucagon secretion
↓ hepatic glucose production
e.g., (gliptins)
- Sitagliptin (Januvia)
- Saxagliptin (Onglyza)
- Linagliptin (Tradjenta)
- Incretin hormones are released by the intestines throughout the day, but lvls inc in response to a meal
> when glucose lvls are normal or elevated, incretins inc insulin synthesis & release from the pancreas, as well as dec hepatic glucose production
> incretin hormones are normally inactivated by dipeptidyl peptidase-4 (DPP-4)
- DPP-4 inhibitors block the action of the DPP-4 enzyme, which is responsible for inactivating incretin hormones gastric inhibitory peptide [GIP] & glucagon-like peptide [GLP-1]
> result is a inc in insulin resistance, a dec in glucagon secretion, & dec hepatic glucose production
- B/c the DPP-4 inhibitors are glucose dependent, they lower the potential for hypoglycemia
- Main benefit of these drugs over other rx’s for DM w/similar s/e’s is the absence of wt gain as a s/e
! DPP-4’s & incretin mimetics cause an increase in pancreatitis
Dopamine Receptor Agonist
Bromocriptine (Cycloset)
* MoA unknown
* Thought that pts w/type 2 DM have low lvls of dopamine
* Increases dopamine receptor activity
* Alone or in combination
Drug Therapy: Glucagon-like Peptide Receptor Agonists
Stimulate glucagon-like peptide-1 (GLP-1)
* Increase insulin synthesis & release from the pancreas
* Inhibit glucagon secretion
* Decrease gastric emptying
* Increases satiety
- Must take fast-acting oral meds 1 hr before SC injection exenatide (Byetta) & liraglutide (Victoza)
- Albiglutide (Tanzeum) injected only once weekly
Exenatide (Byetta)
! Acute pancreatitis & kidney problems have been assoc w/use
Liraglutide (Victoza)
! Don’t use in pts w/a personal or fhx of medullary thyroid cancer; acute pancreatitis has been assoc w/use
Drug Therapy: Amylin Analog
Pramlintide (Symlin)
- Slows gastric emptying, reduces postprandial glucagon secretion, increases satiety
- Used concurrently w/insulin
! Can’t be mixed in same syringe w/insulin
- SC in thigh or abdomen before meals
! Watch for (severe) hypoglycemia & n/v
