Treating diabetes


Type 1 diabetes

Thanks to multiple studies done all over the world, there is now extensive evidence on the optimal management of type 1 diabetes. This offers people with type 1 diabetes the opportunity to improve their immediate and long-term quality of life.

If you have type 1 diabetes, your pancreas produce very little or no insulin and you risk diabetic ketoacidosis, a life-threatening complication characterised by severe disturbances in carbohydrate, protein and fat metabolism. The recommended treatment for type 1 diabetes is, therefore, insulin. There really are no other alternatives.

Insulin treatment must be started as soon as possible after diagnosis and will continue for the rest of your life. Good technical skill in terms of using syringes, insulin pens and pumps (if applicable) is important. Your healthcare team will be able to assist you in mastering these tools.

In addition to taking insulin, you’ll have to follow a healthy, active lifestyle that includes a balanced, nutritious diet. It’s important to work closely with a registered dietitian as well as your doctor, as you’ll have to learn how to manage the amount of carbohydrate you eat, the amount of exercise you do, and the insulin you have to take.

The different types of insulin

Before human insulin was developed, animal insulin was used for insulin therapy. This was usually a form of purified pig insulin.

The first generation of man-made insulin – “human insulin” – was developed throughout the 1960s and 1970s and was approved for pharmaceutical use in 1982. It’s a synthetic insulin “grown” in the laboratory to mimic the insulin produced by the human pancreas.

A new type of synthetic insulin was developed in the late 1990s. “Analogue insulin” is also created in the laboratory, but is genetically altered to produce either more rapid or more uniform effects on blood-glucose levels.

Insulin has three characteristics:

  • Onset: The length of time before the insulin reaches the bloodstream and begins to lower blood glucose.
  • Peak time: The time during which the insulin is at its maximum strength in terms of lowering blood glucose.
  • Duration: How long the insulin continues to lower blood glucose.

Using these characteristics, insulin is classified into different types:

  • Rapid-acting insulin begins to work about 15 minutes after injection, peaks in about 1 hour, and continues to work for 2-4 hours. Types: Insulin glulisine (Apidra), insulin lispro (Humalog), insulin aspart (Novorapid)
  • Regular or short-acting insulin usually reaches the bloodstream within 30 minutes after injection, peaks anywhere from 2-3 hours after injection, and is effective for approximately 3-6 hours. Types: Humulin R, Actrapid, Biosulin R
  • Intermediate-acting insulin generally reaches the bloodstream about 2-4 hours after injection, peaks 4-12 hours later, and is effective for about 12-18 hours. Types: NPH (Humulin N, Protaphane, Biosulin N)
  • Long-acting insulin reaches the bloodstream several hours after injection and tends to lower glucose levels fairly evenly over a 24-hour period. Types: Insulin detemir (Levemir), insulin glargine (Lantus, Basaglar, Optisulin,Toujeo)
  • Ultralong-acting insulin, which has just been launched, has a duration of action of up to 42 hours. This makes it a once-daily basal insulin. Types: Insulin degludec (Tresiba)

Insulin type



Duration of action



  • Lispro

5-15 min.

30-60 min.

3-4 hours


  • Aspart

10-20 min.

40-50 min.

3-5 hours


  • Glulisine

20 min.

1 hour

4 hours




  • Regular

30 min.

60-120 min.

6-8 hours




  • NPH

1-2 hours

3-8 hours

12-15 hours



  • Glargine

1.2 hours


24 hours


  • Determir

1.6 hours


24 hours


(Source: Morello 2011)

Premixed insulin

Insulin is also available in premixed form. NPH insulin (Humulin N, Protaphane, Biosulin N) may be mixed with both rapid-acting insulin analogues and fast-acting human regular insulin. These mixtures include various combinations:

  • In South Africa, lispro (Humalog), the rapid-acting insulin, is mixed with NPH in a 50:50 mix (50% NPH and 50% insulin lispro). This is called Humalog Mix50. It’s also mixed in a 75:25 ratio (75% NPH and 25% insulin lispro) and sold as Humalog Mix25.
  • Insulin aspart combinations are also available as 70:30 mixtures (70% NPH, 30% insulin aspart). This is sold under the Novomix brand name.
  • The traditional NPH ratio of regular pre-mixed insulin, 70:30 (70% NPH, 30% regular), is still available. These insulins are available as vials and as insulin pens (Actraphane and Biosulin 30/70).
  • The first-ever mix with both long- and short-acting analogue insulin is Ryzodeg, which has rapid-acting insulin aspart mixed with ultralong-acting basal insulin analogue decludec in a 30:70 combination.

In South Africa, insulin is sold in vials, cartridges and pre-filled pens at a standard strength of 100 units per millilitre. Recently a new product (glargine), with a strength of 300 units per millilitre, has been added to the long-acting range.

Insulin regimens

In healthy people, insulin is secreted by the pancreas at a constant, low level over 24 hours. This prevents glucose release by the liver, which may occur via the process of gluconeogenesis (when glucose is produced from non-carbohydrate sources such as amino acids from protein) and glycogenolysis (when the carbohydrate, glycogen, is broken down into glucose). Insulin secretion is increased during and after meals when the digestion of food leads to an increase in blood glucose. The insulin helps to keep the blood-glucose levels within a normal range.

In treating type 1 diabetes, the aim is to mimic normal insulin secretion. This is best done by the so-called “basal bolus regimen”, where a long-acting insulin (basal) is given once a day, at the same time every evening. Sometimes this is split into two doses for children (especially those of school age), with the second dose given in the morning.

The aim of the basal bolus regimen is to provide a 24-hour basal insulin supply with the goal of keeping the fasting blood-glucose level between 4 and 7mmol/l. Rapid-acting or short-acting insulin is then taken before meals to cover meal-time surges in glucose. This usually involves up to three insulin injections during the day.

The basal bolus regimen therefore usually involves up to four or more injections per day. It gives the individual some flexibility, better blood-glucose control and fewer hypoglycaemic episodes (when there’s too little glucose in the bloodstream), especially if analogue insulin is used.

Insulin pumps

Continuous subcutaneous insulin pumps (CSIIs) are a good option for mimicking normal insulin secretion. Rapid-acting insulin, delivered via a needle or soft tube inserted under the skin, is used in these small, computerised devices.

Insulin pumps are useful in the following instances:

  • Type 1 diabetes
  • Recurrent hyperglycaemia (elevated blood-glucose levels)
  • Hypoglycaemia unawareness (when you don’t experience or perceive the symptoms of low blood-glucose levels)
  • Dawn phenomenon (an abnormal, early-morning increase in blood glucose)
  • Difficulty managing diabetes while pregnant
  • Gastroparesis (delayed gastric emptying)
  • In post-renal transplant patients

Research shows that these pumps are much more effective in reducing the frequency and severity of complications in teenagers and adults with type 1 diabetes than multiple daily injections. The pump continuously delivers pre-determined basal rates to meet insulin requirements when you’re not eating. A bolus dose can also be given during a meal or snack time.

Advantages include increased flexibility in lifestyle and more precise insulin delivery, which ultimately improves glycaemic control and reduces the risk of complications. The disadvantages are that, if the flow of the insulin is disrupted, you can go into diabetic ketoacidosis. The catheter site can also become infected, and there’s a risk for weight gain.

To prevent diabetic ketoacidosis if you’re using a pump, it’s essential to monitor your glucose levels every 4-6 hours.

Using premixed insulin

Another simple regimen is to use twice-daily premixed insulin at breakfast and supper time. In some people, a third dose is needed at lunchtime.

The treatment that’s best for youYour doctor will work with you to decide on the type of insulin and the type of regimen that will be best for you. Making that choice will depend on a number of factors, including:

  • Your age.
  • How you respond to insulin, i.e. how long it takes your body to absorb it and how long it remains active. This varies from person to person.
  • Your lifestyle – the type of food you eat, how much alcohol you drink, and how much exercise you get, as these factors affect how your body uses insulin.
  • Your willingness to give yourself multiple injections per day.
  • How often you check your blood-glucose levels.
  • Your goals for managing your blood-glucose levels.

Note that every person with diabetes is prescribed their own appropriate dose. Don’t compare your dose to someone else’s, as the other person’s circumstances may be very different to your own.

Insulin storage

Storing your insulin correctly is incredibly important.

Take note of the following:

  • Unused insulin should be stored in a refrigerator between 4°C and 8°C.
  • Insulin must never be frozen.
  • Insulin must be kept away from direct sunlight and hot temperatures.
  • Never use insulin that has changed appearance (e.g. clumping, frosting, precipitation, discolouration).
  • After first usage, an insulin vial should be discarded after 3 months if kept at 2-8°C, or 4 weeks if kept at room temperature. However, for some insulin preparations, manufacturers recommend only 10-14 days of use at room temperature. Read the package inserts carefully. 

Type 2 diabetes 

If you have type 2 diabetes, your lifestyle and/or medication will have to work together to bring your blood-glucose levels under control. Your doctor will help you to determine whether you need to take medicine, which kind of medicine is right for you, and how often you should take it.

Over your lifetime, you’ll probably have to manage your condition in different ways. First you may only have to make lifestyle changes. Later, you may have to start taking medicine. At some point, one of your medications may stop working, and you’ll have to switch to something else or add a new drug. You’ll need to adjust to changes in your body as you age.

The key principles of medical management are:

  • Regular blood-glucose self-monitoring as a part of daily living.
  • Taking diabetes medication such as pills, injected medicines or even insulin, if prescribed.
  • Problem solving how and when to make adjustments in your medication doses to prevent high or low blood-glucose levels.
  • Understanding complications and how to screen for, prevent and treat them.

Lifestyle changes

If you have type 2 diabetes, you should consult with a registered dietitian as soon as possible after your diagnosis. It’s best to work from a personal eating programme that has been tailored to your exact needs and preferences.

Talk to your dietitian about how to manage portion sizes (see a picture of what your plate should look like below), how to read food labels, how to keep track of your carbohydrate intake, and how to make healthy choices when you’re eating out and shopping for food.

Physical activity should also form an integral part of your treatment plan. Exercise will improve your insulin sensitivity, reduce your cardiovascular risk factors, control your weight, and improve your overall wellbeing. After your doctor has given you the green light to exercise, you should aim for at least 150 minutes per week of moderate-intensity aerobic exercise (50-70% of maximum heart rate) or at least 90 minutes of vigorous aerobic exercise per week.

It’s furthermore incredibly important to stop smoking if you are a smoker.


Many people with type 2 diabetes – even those who follow their prescribed diet and exercise regularly – need to control their blood glucose with medication.

The broad range of metabolic defects that are associated with type 2 diabetes also often require treatment with combinations of more than one drug. Increasing doses of medication and insulin injections may be required to control your blood glucose as you grow older. This is why it’s important to have your blood-glucose levels checked regularly by your doctor.

Medication to regulate blood-glucose levels include:

  • Non-insulin oral medication 
  • Insulin
  • Non-insulin injectable medication (GLP-1 agonists)

Non-insulin oral medication

Most of these medicines are available in tablet form. The different non-insulin oral medications differ in their modes of action, side effects, cost and dosing schedule, and the choice of the most suitable one will be made after a full medical assessment.

The main groups are:

  • Biguanides (metformin). Metformin is generally the first medication prescribed for type 2 diabetes. It works by improving the sensitivity of the tissues to insulin so that the body can use it more effectively. Metformin also lowers glucose production in the liver.
  • Sulphonylureas (glyclazide or glimepiride). These help the body to secrete more insulin.
  • Thiazolidinediones (pioglitazone). Like metformin, these drugs make the body’s tissues more sensitive to insulin.
  • DPP-4-inhibitors (sitagliptin, vildagliptin, saxagliptin). These drugs increase incretin levels (GLP-1 and GIP), which inhibit glucagon release. This, in turn, increases insulin secretion, decreases gastric emptying, and decreases blood-glucose levels.
  • Alpha-glucosidase inhibitors. These drugs delay carbohydrate digestion.
  • SGLT2 inhibitors (dapagliflozin, empagliflozin). These are the newest diabetes drugs on the market. They work by preventing the kidneys from reabsorbing glucose into the blood. Instead, the glucose is excreted in the urine.


In order to adequately control blood-glucose levels, most people with type 2 diabetes will need insulin at some stage.For years, doctors only prescribed insulin therapy for people with type 2 diabetes as a last resort. Now experts advocate earlier introduction of insulin because it protects the remaining insulin-producing cells in the pancreas. Insulin treatment shouldn’t be delayed if your blood-glucose levels aren’t adequately controlled with oral medication, as this may lead to complications.

Non-insulin injectable diabetes medication

The GLP-1 receptor agonists (e.g. exenatide, liraglutide) affect glucose control through several mechanisms. These include increasing insulin release when you eat, keeping food in the stomach for longer, and lowering the amount of glucose released by the liver. 

Gestational diabetes

Gestational diabetes can often initially be managed with a healthy eating pattern and regular physical activity. However, approximately 10-20% of women diagnosed with gestational diabetes have to use insulin injections throughout their pregnancy. Insulin pumps can also be used during this time.

If gestational diabetes isn’t well controlled and blood-glucose levels remain too high, the condition may result in complications such as miscarriage, stillbirth or a large-for-gestational-age baby. A large baby increases the risk of injury during delivery, caesarean delivery, forceps delivery, and a need for the baby to be looked after in a special-care unit to stabilise glucose levels after delivery. Another possible complication is premature delivery.

It’s important to monitor your blood-glucose levels at home and to ensure that they’re kept within the target range. Your doctor or diabetes educator will give you guidance on your recommended blood-glucose target levels and testing times.

If your blood-glucose levels cannot be managed with a healthy eating pattern and regular physical activity, your doctor may suggest medication. Most diabetes tablets aren’t suitable for use during pregnancy, but insulin injections and/or metformin is safe if taken as prescribed.

Gestational diabetes, if untreated, can pose a serious risk to the health of both the mother and her unborn child. The condition can also greatly increase the risk of miscarriage, still-birth and serious birth defects.

The good news is that through proper control and treatment, these risks are greatly reduced. Many mothers with gestational diabetes experience healthy pregnancies by following treatment guidelines.

Treating gestational diabetes means taking steps to keep your blood glucose levels in a normal blood sugar target range. You will learn how to control your blood glucose with a strict meal plan, some physical activity and appropriate medication advised by your specialist.

How will I know whether my blood glucose levels are on target?

Your health care team may ask you to use a small device called a blood glucose meter (glucometer) to check your levels on your own.

You will learn:

  • How to use the meter
  • How to prick your finger to obtain a drop of blood
  • What your target range is
  • When to check your blood glucose

You may be asked to check your blood glucose:

  • When you wake up
  • Just before meals
  • 2–3 hours after breakfast
  • 2–3 hours after lunch
  • 2–3 hours after dinner

Eating well with gestational diabetes

Your diet is an incredibly important part of managing gestational diabetes. Following a healthy eating plan will assist in:

  • Managing your blood-glucose levels and keeping them within the target range advised by your doctor.
  • Providing adequate nutrition for you and your growing baby.
  • Achieving appropriate weight changes during your pregnancy.

Get in touch with a registered dietitian to work out an eating plan for you. Generally, women with gestational diabetes are encouraged to:

  • Maintain a healthy weight.
  • Eat small amounts often.
  • Make some fibre-rich carbohydrates part of every meal and snack (e.g. multigrain bread, bulgur, wholegrain pasta, sweet potato, lentils, butternut, chickpeas, beans).
  • Choose foods that are varied and enjoyable, and which provide the nutrients you need during pregnancy. This includes foods rich in calcium (e.g. milk and cheese), iron (e.g. red meat, chicken and fish), and folic acid (e.g. dark green leafy vegetables).
  • Meals should be lightly cooked and low in fat, particularly saturated fat. Use oils such as canola and olive oil and choose lean meats such as skinless chicken and fish.
  • Go for foods that are high in fibre (e.g. fruit, vegetables, legumes).
  • Avoid foods and drinks that contain large amounts of sugar.
  • Choose basmati rice over normal white rice, as it has a lower glycaemic index and will help you to stay fuller for longer.

After the baby is born, gestational diabetes usually disappears. A special blood-glucose test is performed six weeks after delivery to ensure that your blood-glucose levels have returned to normal. Note, however, that if you’ve had gestational diabetes, you’re at increased risk of developing type 2 diabetes later in life. Be sure to go for regular screenings.

Information and picture supplied by Jeannie Berg, diabetes educator and Chairperson of the Diabetes Education Society of South Africa (DESSA), and reviewed by Dr Joel Dave (MBChB PhD FCP Cert Endocrinology), Senior Specialist in the Division of Diabetic Medicine and Endocrinology, University of Cape Town. August 2018.

Read more:

How is diabetes diagnosed?

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