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Tresiba: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Oct 4, 2021.

1. How it works

  • Tresiba is a brand name for a type of ultra long-acting insulin called insulin degludec.
  • Tresiba is made using genetic engineering technology. Although it resembles human insulin in most of its structure, the amino acid threonine in position B30 has been replaced by a side chain containing glutamine and a C16 fatty acid. Tresiba exists as stable insulin dihexamers bonded by zinc.
  • Once Tresiba is injected, the insulin dihexamers form multihexamers. The rate of insulin absorption depends on the size of the insulin molecules, so these large insulin hexamers stay in place, creating an insulin depot (storage). With time the zinc diffuses, which releases insulin monomers from each end of the chain. These monomers are the correct size for absorption into the bloodstream.
  • Because of the slow and steady way Tresiba breaks up and diffuses under the skin, it lasts for at least 42 hours. This means Tresiba can be dosed once a day, at any time of the day.
  • The primary activity of insulin, which includes Tresiba, is to allow cells throughout the body to uptake glucose (sugar) and convert it into a form that can be used by these cells for energy.

2. Upsides

  • Ultra-long acting. Lasts for at least 42 hours which means it can be dosed once a day, at any time of the day.
  • May be used for the treatment of type 1 or type 2 diabetes in adults and children over the age of one who require an ultra long-acting insulin for their diabetes control.
  • Tresiba is available in two concentrations U-100 and U-200. No dose conversion is necessary when switching from the U-100 to the U-200 pen as the dose window shows the number of insulin units to be delivered and no conversion is needed.
  • Tresiba U-100 is available in a convenient prefilled FlexTouch pen that is for single patient-use and contains 300 units of Tresiba U-100. This pen delivers doses in 1 unit increments and can deliver a maximum of 80 units in a single injection. Tresiba U-100 is also available as a multiple-use 10ml vial.
  • Tresiba U-200 is available as a convenient prefilled FlexTouch pen that is for single patient-use and contains 600 units of Tresiba U-200. This pen delivers doses in 2 unit increments and can deliver a maximum of 160 units in a single injection. Tresiba U-200 is not available in a vial.
  • Tresiba does not pass into breast milk and will not affect a nursing infant.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Low blood sugar levels (hypoglycemia) are the most common side effect of Tresiba; however, the risk of hypoglycemia is lower with Tresiba than it is with insulin glargine. The risk of hypoglycemia increases with tighter blood sugar controls, changes in meal patterns, with certain coadministered medications, and changes in physical activity levels. People with liver or kidney disease may be at a higher risk of hypoglycemia.
  • All insulins can cause potassium levels to go low (this is called hypokalemia). Insulin may also cause sodium retention, weight gain, fluid retention and swelling, itching, redness, or lumps around the injection site. There is a risk of infection if a Tresiba FlexTouch pen is shared.
  • The dosage of Tresiba may need to be reduced in liver or kidney disease. Blood glucose levels should be carefully monitored in people with these conditions.
  • Seniors may be more susceptible to the side effects of ultra long-acting insulins, such as insulin degludec. The dosage of Tresiba in elderly people should be conservative.
  • Tresiba must be given by subcutaneous (under the skin) injection. It should not be given by IV, IM, or via an infusion pump.
  • Tresiba is not suitable for the treatment of diabetic ketoacidosis. Short-acting insulins should be used to treat this condition.
  • Seniors may have more difficulty using the Tresiba FlexTouch pen due to poor vision or dexterity problems, making it difficult to dial the correct dosage or inject the insulin under their skin.
  • Tresiba must be given by subcutaneous (under the skin) injection, once daily.
  • Studies that investigated the use of insulin, such as Tresiba during pregnancy, have not identified a clear association with insulin and adverse developmental outcomes. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy such as diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, and delivery complications. The risk of major birth defects is 6% to 10% in women with pregestational diabetes with an HbA1c >7 and has been reported to be as high as 20% to 25% in women with an HbA1c >10. In general, the benefits of using insulin during pregnancy outweigh the risks.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Tresiba contains insulin degludec, an ultra-long acting insulin that starts to work 60 minutes after administration and keeps working for up to 42 hours. Tresiba is approved for use in adults and children over the age of one with type 1 or type 2 diabetes.

5. Tips

  • Tell your doctor if you have ever had an allergic reaction to any type of insulin before you start using Tresiba.
  • Children are especially sensitive to the effects of insulin, particularly around puberty.
  • There are so many different types of insulin that medication errors are common. Always check the label on your insulin to make sure it is the right concentration (U-100 or U-200) and the right brand. Talk to your doctor or pharmacist if you are unsure. Always make sure you dial up the correct dose of Tresiba for you.
  • The dosage of Tresiba needs to be individualized. This may take time, so ensure you monitor your blood sugars regularly when titrating the dosage of Tresiba, and tell your doctor the results.
  • Never share your Tresiba FlexTouch pen with other people. Store your pens as recommended on the label.
  • Inject your insulin exactly as directed by your doctor. Take all other medications as prescribed.
  • Your insulin requirements may change if you become unwell, develop an infection, or other medical conditions. Surgery, injury, mental stress, your diet, and how much exercise you do can also affect how much insulin you need. Puberty, pregnancy, and menopause can also affect insulin requirements. Conditions that delay food absorption or stomach emptying can slow down the time it takes to break down and absorb food which can change how much insulin you need.
  • Be alert for symptoms of hypoglycemia which may include a headache, sweating, trembling, anxiety, confusion, irritability, rapid breathing, or a fast heartbeat. People with hypoglycemia may also faint and severe hypoglycemia that is left untreated may be fatal. Tell your family, friends, and caregivers to give you some fast-acting sugar (such as some jellybeans, fruit juice, or honey) if they notice you have symptoms of hypoglycemia and then follow it up with a more substantial meal or glucagon injection if you are unconscious.
  • Insulin is easily broken down by extreme temperatures, which means you need to be careful if you live in a part of the U.S. that gets very hot in summer, or very cold in winter.
  • Tresiba that has been opened may be kept at room temperature (59 to 77 degrees Fahrenheit [15-25 degrees Celcius]) for up to 56 days (8 weeks), much longer than most other insulins that can only be left unrefrigerated for up to 28 days.
  • If you are going out in the sun, always use an insulated bag protected by a cool pack to ensure your Tresiba doesn't heat up; but avoid freezing it. During cold weather, keep your Tresiba close to your skin so your body heat keeps it at a more even temperature. Discard any Tresiba pens that you think may have inadvertently got too hot or too cold. The expiry date on Tresiba applies to unopened, refrigerated insulin.
  • If you become pregnant while on Tresiba, tell your doctor immediately. Controlling diabetes during pregnancy is very important and high blood sugar levels can be detrimental both to you and your developing baby.

6. Response and effectiveness

  • Trials have shown that Tresiba is just as effective as Lantus and Levemir at achieving blood glucose control and lowering HbA1c levels.
  • Tresiba is less likely than insulin glargine to cause severe hypoglycemia.

7. Interactions

Medicines that interact with Tresiba may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Tresiba. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Tresiba include:

  • antibiotics, such as doxycycline and minocycline
  • antidepressants such as SSRIs (eg, fluoxetine, sertraline), monoamine oxidase inhibitors (MAOI) such as selegiline, isocarboxazid, and phenelzine
  • antiepileptics, such as fosphenytoin and phenytoin
  • antipsychotics, such as aripiprazole, chlorpromazine
  • antivirals such as amprenavir, atazanavir, and fosamprenavir
  • aspirin
  • beta-blockers, such as acebutolol, atenolol, or timolol
  • cyclosporine
  • diuretics, such as furosemide, chlorthalidone, or hydrochlorothiazide
  • fluoroquinolone antibiotics, such as ciprofloxacin or norfloxacin
  • gemfibrozil
  • heart medications such as captopril, candesartan, or clonidine
  • hormones, such as estradiol, estrone, and norethindrone
  • lithium
  • niacin
  • pentamidine
  • salmeterol
  • steroids, such as cortisone, dexamethasone, fludrocortisone, or prednisone
  • sucralfate
  • tacrolimus or pimecrolimus
  • topiramate
  • turmeric
  • aloe vera
  • other insulins
  • other medications that affect blood sugar levels or are used for diabetes, such as chlorpropamide, glimepiride, or glipizide.

Alcohol may also interact with Tresiba by blocking the production of glucose by the liver, causing hypoglycemia.

Note that this list is not all-inclusive and includes only common medications that may interact with Tresiba. You should refer to the prescribing information for Tresiba for a complete list of interactions


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Tresiba only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2022 Revision date: October 4, 2021.