Type 1 diabetes results in high blood sugar levels because the body stops producing insulin, the hormone that regulates sugar levels. Type 2 diabetes leads to high blood sugars because the insulin in the body does not work effectively.
The broad differences in treatment between the two types are:
- Type 1 diabetes is treated with insulin injection. Careful diet and activity planning is needed to avoid complications of treatment.
- Type 2 diabetes is treated with lifestyle measures, drugs taken by mouth, and sometimes also insulin if the other treatments fail.
Medications for type 1 diabetes
Treatment for type 1 diabetes is always with insulin, to replace the body's absent insulin and keep blood sugar levels under control.
Type 1 diabetes is always treated with insulin. Many patients inject insulin themselves.
Insulin is usually given by injection - by patients themselves, injecting it under the skin, or if hospitalized, sometimes directly into the blood. It is also available as a powder that patients can breathe in.
Insulin injections vary by how quickly they act, their peak action, and how long they last. The aim is to mimic how the body would produce insulin throughout the day and in relation to energy intake.
1. Rapid-acting injections take effect within 5 to 15 minutes but last for a shorter time of 3 to 5 hours:
- Insulin lispro (Humalog)
- Insulin aspart (NovoLog)
- Insulin glulisine (Apidra)
2. Short-acting injections take effect from between 30 minutes and 1 hour, and last for 6 to 8 hours:
- Regular insulin (Humulin R and Novolin R)
3. Intermediate-acting injections take effect after about 2 hours, and last for 18 to 26 hours:
- Insulin isophane, also called NPH insulin (Humulin N and Novolin N)
4. Long-acting injections take effect after 1 or 2 hours and last for between 14 and 24 hours:
- Insulin glargine (Lantus)
- Insulin detemir (Levemir)
5. Premixed injections are combinations of the above types of insulin. All take effect from between 5 minutes and 1 hour, and last for between 10 and 16 hours:
- Insulin lispro protamine/insulin lispro (Humalog Mix50/50 and Humalog Mix75/25)
- Insulin aspart protamine/insulin aspart (NovoLog Mix 50/50 and NovoLog Mix 70/30)
- NPH insulin/regular insulin (Humulin 70/30 and Novolin 70/30)
6. Rapid-acting inhaled insulin is breathed in, takes effect within 12 to 15 minutes, and lasts for 2.5 to 3 hours:
- Insulin human powder (Afrezza)
Other drugs for type 1 diabetes
Metformin is added in for some people with type 1, but it is a drug mainly for type 2 diabetes. The following drugs are also used in type 1 diabetes and are all grouped together as non-insulin injectables:
- Incretin mimetics are drugs that mimic the body's hormone incretin, which stimulates insulin release after meals: exenatide (Byetta, Bydureon), liraglutide (Victoza), and dulaglutide (Trulicity)
- Amylin analogs: pramlintide (Symlin) mimics another hormone, amylin, that is involved in glucose regulation
- Glucagon is used to reverse blood sugar levels when they fall too low as a result of insulin treatment
Medications for type 2 diabetes
People with type 2 diabetes will only use insulin when other treatments haven't worked.
Insulin can also be used to manage high blood glucose levels in type 2 diabetes, but only when other treatments have failed to work. Women with type 2 diabetes who become pregnant may also use it to reduce effects on the fetus.
In people who still have high blood glucose levels in spite of lifestyle measures, non-insulin drugs to lower blood glucose levels can be prescribed. These drugs are taken by mouth and listed below.
Many of the drugs are combined for more than one effect. If two or more treatments are needed to control glucose levels, insulin treatment may become needed.
These drugs improve secretion of insulin into the blood by the pancreas. The following newer ones are used most often and are less likely to cause adverse effects:
- Glimepiride (Amaryl)
- Glipizide (Glucotrol)
- Glyburide (DiaBeta, Micronase, Glynase)
The older sulfonylureas are:
- Chlorpropamide (Diabinese)
- Tolazamide (Tolinase)
- Tolbutamide (Orinase)
Meglitinides also enhance insulin secretion. These may be more effective at releasing insulin during meals.
- Nateglinide (Starlix)
- Repaglinide (Prandin)
The action of biguanides is to boost the effect of insulin. They reduce the amount of glucose released into the blood by the liver. They also increase the uptake of glucose from the blood into the cells.
Metformin is the only biguanide that is licensed in the United States (Glucophage, Glucophage XR, Glumetza, Riomet, Fortamet).
Thiazolidinediones reduce the resistance of tissues to the effects of insulin. They are relatively new diabetes drugs so need monitoring for potential safety issues. They should not be used in patients with heart failure.
- Pioglitazone (Actos)
- Rosiglitazone (Avandia)
Alpha-glucosidase inhibitors cause carbohydrates to be digested and absorbed more slowly. This lowers glucose levels in the blood after meals.
- Acarbose (Precose)
- Miglitol (Glyset)
Dipeptidyl peptidase inhibitors
This is a relatively new class of medications. One of their effects is to slow the rate of the stomach contents emptying further along the gut, and so slow down glucose absorption.
- Alogliptin (Nesina)
- Linagliptin (Tradjenta)
- Sitagliptin (Januvia)
- Saxagliptin (Onglyza)
Sodium-glucose co-transporter 2 inhibitors
Sodium-glucose co-transporter 2 (SGLT2) inhibitors cause more glucose to be lost from the bloodstream into the urine. They may also produce a modest amount of weight loss, which can be a benefit for type 2 diabetes.
- Canagliflozin (Invokana)
- Dapagliflozin (Farxiga)
- Empagliflozin (Jardiance)
Many diabetes medications are a combination of different drugs.
Oral combination drugs
A variety of products that combine some of the drugs mentioned above is available. These include:
- Alogliptin and metformin (Kazano)
- Alogliptin and pioglitazone (Oseni)
- Glipizide and metformin (Metaglip)
- Glyburide and metformin (Glucovance)
- Linagliptin and metformin (Jentadueto)
- Pioglitazone and glimepiride (Duetact)
- Pioglitazone and metformin (Actoplus MET, Actoplus MET XR)
- Repaglinide and metformin (PrandiMet)
- Rosiglitazone and glimepiride (Avandaryl)
- Rosiglitazone and metformin (Avandamet)
- Saxagliptin and metformin (Kombiglyze XR)
- Sitagliptin and metformin (Janumet and Janumet XR)
One ergot alkaloid, bromocriptine (Cycloset), is approved for type 2 diabetes. It is not recommended alongside other diabetes drugs.
Bile acid sequestrants are used to control cholesterol levels but were found to also control blood sugar levels. Only colesevelam (Welchol) is approved for type 2 diabetes.
Some drugs are used for preventing the complications of diabetes:
- High blood pressure is treated with ACE inhibitors or angiotensin II receptor blockers. These drugs also help prevent or manage kidney complications of diabetes.
- Cardiovascular risks (heart disease and stroke) of diabetes are managed by taking statins to lower cholesterol levels, and a low-dose aspirin once every day unless aspirin cannot be taken.
Losing weight is a key part of diabetes management and prevention. Drugs may be used to help with this, too, if lifestyle measures have not worked.
- Lorcaserin (Belviq), which increases the feeling of being full after food
- Orlistat (Alli and Xenical) reduces fat absorbed from the diet
- Phentermine and topiramate (Qsymia) is a combination drug that suppresses appetite
Insulin cannot be taken by mouth because the stomach breaks down the hormone. This means the main way it reaches the bloodstream is after injection under the skin or by insulin pump.
Other routes have been tried, but require more study:
- Across the internal surfaces known as the mucosal membranes by nasal or oral spray
- Afrezza was approved in June 2014 by the U.S. Food and Drug Administration as an inhaled powdered insulin to use with long-acting injections
- Across the skin (without needles) - transdermal delivery systems such as patches
The idea of an artificial pancreas is an ongoing area of research. This would use sensors to monitor blood sugar levels electronically to release the amount of insulin needed.
The cells of the pancreas that have failed to produce insulin could also be transplanted from donors. Some patients are already benefiting from early research progress with islet cell transplants.
Personalized medicine is an area showing promise for the treatment of all types of diabetes. Better grouping of the diseases and therefore more targeted treatment may result from the developments in genetics and big data.