By Emeritus Professor Datuk Dr Mustaffa Embong
KUALA LUMPUR: People with diabetes who are not treated (or do not control their diabetes well) have blood glucose levels (much) higher than non-diabetics.
Healthy eating (avoiding sugary foods, reducing carbohydrates and cutting down on calories if overweight or obese) and regular physical activity are the mainstays of keeping diabetes under control.
It is estimated that about 30 to 40 per cent (some say up to 60 per cent) of people with diabetes type 2 can achieve their blood glucose targets just by adopting a healthy lifestyle with healthy eating and regular exercise (and keeping to ideal body weight) as mentioned above.
Unfortunately, many are not able to achieve targets with lifestyle adjustments alone – mostly because they are not strict with their diet control and not physically active – because they have had diabetes for a long time.
In such circumstances, these individuals are prescribed medications to help manage their blood glucose levels. Most of these medications are in the form of tablets but some medications, for example insulin, are given by injection.
Oral medications
There are six major groups of oral medications for people with diabetes in Malaysia. These tablets, referred to as Oral Hypoglycaemic Agents (OHAs), work differently in lowering your blood glucose levels.
Your doctor will decide which type of oral drug is most suitable for you and whether you only need to take a single drug or a combination of drugs (including insulin) to get you to achieve your target HbA1c level.
You must always take your diabetes medication as prescribed by your doctor. Do not alter the dose or schedule of your medication without first consulting your diabetes care team.
GROUPS/TYPES OF ORAL HYPOGLYCAEMIC AGENTS (OHAs)
| Group / Types | Action | Examples |
| Sulphonylureas (SUs) and Meglitinides (‘glinides’) | Stimulate the pancreas to release more insulin | ‘Daonil’,
‘Diamicron-MR’, gliclazide, ‘Amaryl’ and ‘Novonorm’ |
| Biguanides | Reduce glucose released by the liver, slow absorption of glucose from the intestine, and help the body to become more sensitive to insulin so that your own insulin works better | ‘Glucophage-XR’, Metformin |
| Thiazolidinediones (‘glitazones’, TZDs) | Reduce insulin resistance, allowing your own insulin to work more effectively especially on muscles and fat cells | ‘Actos’ |
| Alpha-glucosidase inhibitors | Delay breakdown of complex carbohydrates in the intestines thus slowing the rise in blood glucose levels after food | ‘Glucobay’, Acarbose |
| Dipeptidyl peptidase-4 Inhibitors (DPP4-I) | Increase insulin and reduce glucagon release associated with food intake | ‘Januvia’;‘Galvus’; ‘Onglyza’, ‘Tragenta’ |
| Sodium-glucose Co-transporter inhibitors
(SGLT2-Is) |
Reduce absorption of glucose by the kidneys so that excess glucose is excreted in the urine. Associated with weight loss, heart and kidney protection. | ‘Forxiga’, ‘Jardiance’, ‘Invokana’ |
Precaution
Oral diabetes medications are not without side-effects, the one of most concern being hypoglycaemia (low blood glucose level). This is likely to occur if we take a sulphonylurea such as ‘daonil’ (glibenclamide) or a meglitinide (for example, ‘Novonorm’).
Other OHAs usually do not cause hypoglycaemia (or hypo), unless they are taken in combination. If you develop hypo, make sure that you know how to manage it well. Ask your doctor if you are not sure.
Another problem people on OHAs may encounter is weight gain. This is worrying as many people with type 2 diabetes are usually overweight or obese; weight increase would make their diabetes more difficult to control.
Sulphonylureas, meglitinides (and TZDs) may cause weight gain while other tablets are weight neutral (DPP4-I, for example, januvia) or even may cause weight loss (biguanides, for example, metformin; SGLT2-I, for example, forxiga).
Allergic reactions may occur in people taking an OHA, the most common being skin rashes. More serious reactions are rarely seen, such as swollen lips, skin blistering or difficulty in breathing. If you have such severe reactions, stop the medication and seek medical help immediately.
Other side-effects are more group-specific. These include gastrointestinal effects such as abdominal pain, flatulence, bloating and diarrhoea which are commonly seen in those prescribed a biguanide (‘metformin’), DPP4-I (‘galvus’) or an alpha-glucosidase inhibitor (‘acarbose’). To avoid/minimise the effects, your doctor may start the medication at a low dose and increase it only slowly.
One reason for the weight gain in people taking a TZD (‘actos’) is due to water retention. For this reason, the drug is contra-indicated in diabetics with (or prone to) heart failure. TZD may also increase the risk of bone fracture.
People taking an SGLT2-I tablet (for example, ‘jardiance’) are more prone to urinary tract infections or genital thrush because of the increased amount of glucose in the urine. They may also develop giddiness due to excessive loss of water leading to low blood pressure. As a precaution, diabetics taking SGLT2-I tablets are advised to practice good hygiene after passing urine and to drink a lot of plain water.
Always inform your doctor if you experience side-effects (or are not comfortable) with a tablet. He/she will adjust the dose or provide you with an alternative medicine.
Some of the drugs used to treat diabetes are contraindicated in people with certain conditions. As mentioned above, TZDs cannot be used in people with heart failure or prone to fracture. Similarly, drugs such as TZDs and biguanides are not recommended for those with liver impairment while metformin, SGLT2 and most SUs and DPP4-Is are contra-indicated in diabetics with (severe) kidney disease.
It is important to note that most OHAs are not recommended for those who are (or intending to be) pregnant or planning to breastfeed. Please inform your doctor of your intention so that a safer medication can be prescribed.
Reminder
In concluding this discussion, it is important for us to again stress that these medications are to help us control our diabetes, that is, to be used in addition to (not instead of) our adoption of healthy eating and regular exercise.
Medications alone, however good they are – without due attention to diet and increased physical activity – will not be able to control our diabetes well (as many of us must have realised).
Managing your diabetes well is indeed your own personal responsibility, for your own sake and that of your beloved family. We are confident you can do your best to achieve this. – Bernama
The writer Emeritus Professor Datuk Dr Mustaffa Embong is consultant diabetologist at the National Diabetes Institute (NADI). In this first part of his article, he discusses oral medications for people with diabetes.
