Beyond insulin in the treatment of diabetes


At the time of this writing there are a handful of new-fangled diabetes medications out there. Maybe you’ve seen the commercials showing impossibly happy people managing their blood sugar with complete and total ease (this is my favorite!) Or, perhaps you’re seeing these meds pop up in the hospital (or wherever it is that you care for patients). The fact is, there are a LOT of treatments for diabetes that go beyond insulin…but since that’s what we use the most in the clinical setting, let’s start there then we’ll branch out to the fancy stuff. Ready?

Traditional insulins for diabetes

Rapid-acting insulins are used to “cover” your high blood sugar and are intended to be injected about 10-15 minutes prior to eating. They are analogs of naturally-occurring insulin and are the closest thing we’ve got to mimicking your body’s own insulin. Note that fast-acting insulins aren’t just used to cover high blood sugars at mealtime…it can be used when the pt is NPO, though the scale may need to be adjusted, and it can be used q 4 hours if the patient is on tube-feeding around the clock.

Humalog (Insulin Lispro) and Novolog (Insulin Aspart)
solutions are clear
onset 10-15 mins
peaks in 1-2 hrs
lasts 3-4 hrs

Short-acting insulin is typically referred to as “regular insulin” or by its brand names Humulin R and Novolin R. It is the only type that can be given via IV, so if you’ve got a patient on an insulin gtt, this is what they’ll be getting.

Humulin R. and Novolin R.
solutions are clear
onset 30 mins to 1 hour
peaks in 2-4 hrs
lasts 5-7 hrs

Intermediate insulins are used once or twice a day and are essentially “combo” mixtures of insulin isophane and insulin regular. They contain an ingredient (protamine) which causes them to last longer than the rapid and short-acting insulins…this is what gives them their cloudy appearance. Note that  you CAN mix these with rapid and short-acting insulins, but how you draw them up is key! Draw up the clear insulin FIRST, then the cloudy one…you don’t want to get the protamine into your clear insulin. You will typically hear these insulins called ‘NPH’ or they may go by their brand names of Humulin N or Novolin N. I’ve never once seen these used in the hospital…we like to keep things simple.

Humulin N and Novolin N
solutions are cloudy
onset 1-4 hrs
peaks in 6-12 hrs
lasts 24-28 hrs

Basal or long-lasting insulins are typically given once per day to maintain a steady rate of blood sugar control. The most common one is Lantus, but you may also see Levemir. Do not mix long-acting insulins with other types…if you are giving both types, then give in separate syringes and poke your patient twice!

Lantus (insulin glargine) and Levemir (insulin detemir)
solutions are clear
do not mix with other solutions
onset 1 hr
no peak…nice and steady
lasts 24 hrs

Combo insulins are out there, though I’ve never seen them. As mentioned above, in the clinical setting we keep things pretty simple…rapid-acting insulin for standard coverage, regular insulin for IV titration and Lantus for long-term control. However, your patient may be on a combo insulin as part of their home regimen, or maybe you’ll work in outpatient, home health, at a school or somewhere NOT the hospital. These are typically mixtures of rapid-acting and intermediate-acting insulins…how you’ll know you’re dealing with a combo insulin is in the name…it will have some kind of number in the name such as “Humulin 70/30” or “Novolin 70/30.”

Oral medications for diabetes

There’s more to blood sugar control than insulin. Welcome to the exciting world of oral antidiabetic medications!

Sulfonylureas stimulate the pancreas to secrete insulin and increase sensitivity to insulin at receptor sites. Common drug names are Glyburide, Glipizide and Repaglinide.

requires some pancreatic function
effectiveness of warfarin reduced if taken together
can cause photosensitivity
bad side effects with alcohol (abd cramps, headache, hypoglycemia, flushing)
dosing varies, some are once per day others are before each meal

Biguanides decrease glucose production in the liver while increasing glucose utilization by the cells. You’ll see this used a lot in early stages of DM2 and the main one here is Metformin. One of the biggies with this drug is that you can’t take it AND get IV contrast. The patient will have to be OFF metformin the day of the scan and for 48-hrs post IV contrast administration, otherwise it’s bye-bye kidney function.

requires some pancreatic function
common undesirable side effect is diarrhea (give with meals to help alleviate this)
common desirable side effect is weight loss
hold for IV contrast
may cause metallic taste in mouth (transient)

Meglitinides also stimulate the release of insulin, but the mechanism of action has to do with potassium and calcium channels. It is often used in conjunction with metformin or a thiazolidinedione.  Common ones are nateglinide (Starlix) or Repaglinide (Gluconorm)…isn’t that the BEST name for an antidebetic medication? Gluconorm to the rescue!!

requires some pancreatic function
effects increased by a lot of other drugs (warfarin, NSAIDs, simvastatin, etc…)
effects decrease by a lot of drugs (corticosteroids, thyroid drugs, CCBs)

Thiazolidinediones are easy to recognize because they end in the suffix “-zone.” A common one is Actos or pioglitazone (the other is Avandia or rosiglitazone). These drugs improve sensitivity to insulin, so insulin must be present. You’ll often see these drugs used in combo with other antidiabetics…namely Metformin, a sulfonylurea and/or insulin.

requires insulin in order to work
do not give in liver disease
can cause life-threatening CHF
once-per-day dosing

Alpha-glucosidase inhibitors are used for Type 1 diabetes to inhibit the release of the alpha-glucosidase enzyme, which reduces the absorption of dietary glucose. Precose (acarbose) is a common one.

used for Type 1 diabetes along with dietary therapy
can cause abdominal pain, diarrhea and flatulence
may decrease the absorption of digoxin
avoid using with amylase and pancreatin
sign of overdose is an increase in flatulence, diarrhea and GI discomfort
once-per-day, take with a meal

Enzymne inhibitors (Januvia) are used along with diet and exercise to help keep blood sugar under control in patients with Type 2 DM. This is another one you’ll sometimes see along with  metformin, Actos or a sulfonylurea. It works by slowing the inactivation of incretin hormones, which play a role in glucose homeostasis.

not used in Type 1 DM
can increase digoxin levels
excreted in urine, so use cautiously in renal impairment
take once per day, with or without food

SGLT2 inhibitors are one of the newer classes of drugs receiving a lot of attention. They work by increasing renal glucose excretion, increasing insulin sensitivity and uptake in muscle cells, decreasing gluconeogensis, and improving the release of insulin from the pancreas. That’s a lot! Invokana (canagliflozin) is a common one and is used in coordination with diet ane exercise to improve blood glucose control.

PO medication for Type 2 DM
take daily before first meal of the day
not to be used in renal impairment
may cause orthostatic hypotension
common unpleasant side effects are genital infections and frequent urination

Other Injectable Medications

Incretin mimetics / GLP-1 receptor agonists mimic the action of incretin leading to insulin secretion and better blood glucose control. There are a handful of drugs in this class, but the two most common (and interesting) are Byetta and Trulicity.

given SubQ, but is NOT insulin
dosing is twice per day, within 60 mins of morning/evening meal
unpleasant side effects are diarrhea, nausea, vomiting
may decrease absorption of PO meds, especially anti-infectives and oral contraceptives.

given SubQ, but is NOT insulin
dosing is once per week
prescribed when diet/exercise aren’t controlling blood sugar levels
common side effects are stomach pain, diarrhea, loss of appetite
can aid in weight loss

Hormones that aren’t insulin are also used in treating diabetes. Pramlintide (Symlin) works by slowing gastric emptying, suppressing glucagon and regulating food intake (one of the side effects is anorexia). You’ll see Symlin used in diabetics whose blood sugar can’t be well-controlled with insulin…may also see used with sulfonylureas and metformin.

given SubQ, but is NOT insulin
common side effect is nausea and anorexia
avoid using with other meds that decrease GI motility (mainly anticholinergics)
not to be used along with Acarbose
give immediately before a meal

Tresiba (insulin degludec)  is a long-acting basal insulin, so in a way it’s a lot like Lantus. The biggest advantage of Tresiba over Lantus appears to be less incidence of nighttime hypoglycemia. Yay! It is, however, more expensive.

long-acting basal insulin
less incidence of nighttime hypoglycemia
missed doses can be taken within 8 hours of next dose
dose lasts up to 42 hrs, so dosing can be more flexible than with Lantus

Inhaled Insulin (yes, you read that right)

In 2014 the FDA approved an inhaled rapid-acting insulin called Afrezza. It is used in patients with both Type 1 and 2 DM, but if the pt has Type 1 DM they must also be on a long-acting insulin such as Lantus. It comes in two different cartridges…blue is equal to 4 units insulin while green is equal to 8 units and a yellow one is equal to 12 units. Patients combine colored cartridges to come up with their individual dose. Note that dosing can’t be too specific as it has to be as combination of the available cartridges…for example, you couldn’t have someone who needs 6 units as there is no cartridge for that. Because this is an inhaled powder, it is NOT for people with lung issues. In fact, your pt may need to have lung function tests periodically. I guess if your patient is deathly afraid of needles, this might be an option for them.

inhaled rapid-acting insulin
less flexibility with dosing
take right before eating
watch closely for bronchospasm

WHEW! That was a biggun! As always, I hope this helps clear up the complex and exciting world of antidiabetic medications for you…I know I certainly learned a thing or two 🙂

diabetes meds

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