Common Side Effects of Diabetes Medication

Common Side Effects of Diabetes Medication

Medications are active substances that can induce positive effects and adverse reactions. There’s a wide range of different diabetes medications, each working in differing ways. Many people living with diabetes have to take one or more medications to treat their diabetes, which can cause a number of side effects.

What are side effects?

The Oxford Dictionary defines a side effect as:

‘A secondary, typically undesirable effect of a drug or medical treatment.’

All drugs have side effects. In order to find an acceptable treatment, you and your doctor need to balance out the benefits of therapy with the risks and side effects of medication.

Side effects of diabetes medication

Your doctor can prescribe many different diabetes medications. They will work with you to try and find a treatment or combination of drugs that can control your diabetes and protect your health without causing uncomfortable or unpleasant side effects.

Depending on how you react to your therapy, your doctor may change your medication, alter the dose, add another drug or consider injectable treatment with insulin. Side effects of common diabetes medications include:

Metformin side-effects

Metformin is widely used in the UK and internationally. The National Institute for Health and Care Excellence (NICE) recommends that doctors prescribe Metformin as the first line of treatment if type 2 diabetes hasn’t responded to weight loss and dietary measures.

The response to Metformin differs between individuals. If you’re struggling with symptoms, your doctor can start you on a low dose and gradually increase the dose, or they may prescribe a modified-release formulation.

  • Gastrointestinal disturbance: GI problems are common in people taking Metformin. They include abdominal pain, nausea, bloating, and diarrhoea.
    Taking the medication with a meal, reducing the amount of carbohydrates in your diet.
  • Loss of appetite.
  • A metallic taste in your mouth.
  • Hypoglycaemia: Hypos are uncommon with Metformin but are more likely if you also take a sulfonylurea or drink alcohol.
  • Anaemia: Metformin can block vitamin B12 absorption and cause anaemia, especially after long-term use.
  • Lactic acidosis: Rarely Metformin can make lactic acid build up in your bloodstream. It is more likely to happen if Metformin accumulates in the body because of kidney failure, heart failure, or liver disease.
  • Liver inflammation-causing abdominal pain, jaundice, pale stools and dark urine.
  • Skin rash with redness, flushing and itching.

Side effects of sulfonylureas

Sulfonylureas have been extensively used for type 2 diabetes treatment for nearly 50 years. They are generally well-tolerated, and moderated release formulations are available to reduce side effects.

  • Hypos are the most common side effect, especially if you skip meals
  • Weight gain
  • Nausea
  • An itchy, red rash during the first 6-8 weeks of treatment
  • Uncommon and rare side effects include liver problems and a possible impact on heart function

Side effects of alpha-glucosidase inhibitors

Acarbose blocks the absorption of starchy foods. This can improve diabetes control, but it can also cause gastrointestinal disturbance, especially if you eat a high carbohydrate meal. Cutting carbs and gradually increasing the dose can reduce side effects.

  • Abdominal pain and bloating
  • Nausea
  • Diarrhoea
  • Rarely it can cause liver problems, oedema and low platelets

Side effects of prandial glucose regulators

Prandial glucose regulators are generally safe- but they do have some adverse effects.

  • Hypoglycaemia: They can cause hypos, but these are less common than with sulfonylureas
  • Nausea
  • Gastrointestinal disturbance, including diarrhoea and constipation
  • Abdominal pain
  • Allergic skin reactions
  • Liver inflammation

Side effects of SGLT2 inhibitors

SGLT2 inhibitors can be beneficial when you are living with diabetes. However, they can cause complications that you should be aware of so that you can take action if you develop symptoms:

  • Diabetic ketoacidosis (DKA): Diabetic ketoacidosis can develop in people with Type 1 and Type 2 diabetes taking SGLT2 inhibitors. DKA can occur even if your blood glucose level is optimal or near-optimal. If you have symptoms or have raised ketones, you should stop taking the SGLT2s and get urgent medical support. You should continue to take your insulin or other medication
  • Hypoglycaemia: You can get a hypo, especially if you skip meals or take insulin or a sulfonylurea
  • Genital and urinary tract infections
  • Increased urinary frequency
  • Dry mouth and increased thirst
  • Postural hypotension causing dizziness on standing
  • Constipation

Gliptin side effects

  • Gastrointestinal disturbances, including constipation, vomiting, nausea, diarrhoea and indigestion, are the most frequent side effects
  • Headache affects one in a hundred people taking gliptins
  • Dizziness and a tremor
  • Itchy, allergic rash
  • Muscle aches, joint pain and swelling
  • Acute pancreatitis is an uncommon but severe complication
  • Other uncommon side effects include liver inflammation and jaundice, lung disease, impaired renal function and low platelets, bruising and bleeding

Glitazone side effects

The only glitazone currently available in the UK is Pioglitazone. Members of the group of drugs have different side effects. The previously approved glitazone drug Rosiglitazone was linked to an increased risk of heart attack and stroke. As the risks were more significant than the benefits, it was banned in the UK in 2010. These risks are not the same for Pioglitazone. Side effects include:

  • Weight gain
  • Water retention
  • Numbness
  • Chest infections
  • Allergies and skin rashes skin reactions
  • Worsening of osteoporosis and bone fractures
  • Uncommonly it may cause oedema and heart failure, liver problems, macular oedema or anaemia

Incretin mimetics

It’s common to feel nauseous when first starting treatment with an incretin mimetic. It settles over time; you can reduce discomfort by eating bland foods, eating liquid foods like soups and stews and getting up and about after eating.

  • Nausea, vomiting, indigestion, diarrhoea and constipation
  • Problems with hypoglycaemia
  • Insomnia and fatigue
  • Dizziness
  • Dry mouth
  • Inflammation at the injection site
  • Headache
  • More rarely, there may be an increased risk of gallstones, pancreatitis, mental health disturbance, allergies and thyroid tumours

If you are worried about any symptoms, contact your GP, diabetes team or contact accident and emergency. These lists of side effects are not fully comprehensive. Look at the linked pages for more complete lists of potential complications, and always get medical help if you are concerned.


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Carol Willis - Diabetes Clinic Facilitator

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