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  1. About sitagliptin
  2. Key facts
  3. Who can and can't take sitagliptin
  4. How and when to take it
  5. Side effects
  6. Pregnancy and breastfeeding
  7. Cautions with other medicines
  8. Common questions

1. About sitagliptin

Sitagliptin is a medicine used to treat type 2 diabetes. Type 2 diabetes is an illness where the body does not make enough insulin, or the insulin that it makes does not work properly.

This can cause high blood sugar levels (hyperglycaemia).

Sitagliptin is prescribed for people who still have high blood sugar, even though they have a sensible diet and exercise regularly.

Sitagliptin is only available on prescription.

It comes as tablets that you swallow. It also comes as tablets containing a mixture of sitagliptin and metformin. Metformin is another drug used to treat diabetes.

2. Key facts

  • Sitagliptin works by increasing the amount of insulin that your body makes. Insulin is the hormone that controls sugar levels in your blood.
  • You take sitagliptin once a day.
  • The most common side effect of sitagliptin is headaches.
  • This medicine does not usually make you put on weight.
  • Sitagliptin is also called by the brand name Januvia. When combined with metformin it's called Janumet.

3. Who can and can't take sitagliptin

Sitagliptin can be taken by adults (aged 18 years and older).

Sitagliptin is not suitable for some people. To make sure it's safe for you, tell your doctor if you:

  • have had an allergic reaction to sitagliptin or any other medicines in the past
  • have problems with your pancreas
  • have gallstones or very high levels of triglycerides (a type of fat) in your blood
  • are a heavy drinker or dependent on alcohol
  • have (or have previously had) any problems with your kidneys
  • are pregnant or breastfeeding, or trying to get pregnant

This medicine is not used to treat type 1 diabetes (when your body does not produce insulin).

4. How and when to take it

Take sitagliptin once a day.

You can take it at any time - for example, in the morning or in the evening. Just try to take it at the same time every day.

Take your tablet with a glass of water. Swallow the tablet whole, without breaking it.

You can take sitagliptin with or without food.

How much will I take?

Sitagliptin comes as 25mg, 50mg and 100mg tablets.

The usual dose is 100mg a day.

Your doctor might give you a lower dose of 25mg or 50mg a day if you have problems with your kidneys.

What if I take too much?

Urgent advice: Talk to your doctor if you take too much sitagliptin and:

  • have stomach pains
  • are feeling or being sick (nausea or vomiting)
  • feel dizzy
  • are worried

What if I forget to take it?

Take the missed dose as soon as you remember, unless it's nearly time for your next dose.

In this case, skip the missed dose and take your next dose at the usual time.

Do not take a double dose to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you.

You could ask your pharmacist for advice on other ways to remember your medicines.

5. Side effects

Like all medicines, sitagliptin can cause side effects in some people.

But many people have no side effects, or only minor ones.

Common side effects

The most common side effects, which happen in more than 1 in 100 people, are headaches.

Talk to your doctor if headaches last longer than a week or are severe.

If taking sitagliptin gives you a headache, make sure you rest and drink plenty of fluids. Do not drink too much alcohol.

Ask your pharmacist to recommend a painkiller.

Serious side effects

It happens rarely, but some people may have serious side effects after taking sitagliptin.

Call your doctor straight away if you have:

  • severe stomach pains
  • yellowing of your skin, or the whites of your eyes turn yellow

Low blood sugar

Sitagliptin does not usually cause low blood sugar (known as hypoglycaemia, or "hypos") when taken on its own.

But hypos can happen when you take sitagliptin with other diabetes medicines, such as insulin or gliclazide.

Early warning signs of low blood sugar include:

  • feeling hungry
  • trembling or shaking
  • sweating
  • confusion
  • difficulty concentrating

It's also possible for your blood sugar to go too low while you're asleep.

If this happens, it can make you feel sweaty, tired and confused when you wake up.

Low blood sugar may happen if you:

  • take too much of some types of diabetes medicines
  • eat meals irregularly or skip meals
  • are fasting
  • do not eat a healthy diet and are not getting enough nutrients
  • change what you eat
  • increase your physical activity without eating more to compensate
  • drink alcohol, especially after skipping a meal
  • take some other medicines or herbal medicines at the same time
  • have a hormone disorder, such as hypothyroidism
  • have kidney or liver problems

It's important to have regular meals, including breakfast, to prevent hypoglycaemia. Never miss or delay a meal.

If you're planning to exercise more than usual, make sure you eat carbohydrates like bread, pasta or cereals before, during or after exercise.

Always carry a fast-acting carbohydrate with you, like sugar cubes, fruit juice or some sweets, in case your blood sugar level gets low. Artificial sweeteners will not help.

You may also need to eat a starchy carbohydrate, like a sandwich or a biscuit, to maintain your blood sugar for longer.

If taking in sugar does not help or the hypo symptoms come back, contact your doctor or the nearest hospital.

Make sure your friends and family know about your diabetes and the symptoms of low blood sugar levels so they can recognise a hypo if it happens.

Serious allergic reaction

It's possible to have a serious allergic reaction (anaphylaxis) to sitagliptin.

Immediate action required: Call 999 or go to A&E if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of sitagliptin.

For a full list, see the leaflet inside your medicines packet.


You can report any suspected side effect to the UK safety scheme.

6. Pregnancy and breastfeeding

Sitagliptin is generally not recommended in pregnancy or while breastfeeding.

Talk to your doctor, as there may be other medicines you can take instead of sitagliptin.

Non-urgent advice: Tell your doctor if you're:

  • pregnant
  • trying to get pregnant
  • breastfeeding

7. Cautions with other medicines

Some medicines and sitagliptin can interfere with each other.

Some can increase your risk of getting side effects.

Tell your doctor if you're taking:

  • insulin or any other anti-diabetic medicine
  • ketoconazole or itraconazole (medicines for fungal infections)
  • ritonavir (medicine used in treating HIV/AIDS)
  • clarithromycin (antibiotic for treating pneumonia and ear infections)
  • digoxin (medicine for heart conditions, including heart failure)

Make sure that your doctor and pharmacist know you're taking sitagliptin before starting or stopping any other medicine.

Mixing sitagliptin with herbal remedies and supplements

There's very little information about taking herbal remedies and supplements with sitagliptin.


For safety, tell your doctor and pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

8. Common questions

How does sitagliptin work?

Sitagliptin belongs to a group of medicines called dipeptidylpeptidase-4 inhibitors (DPP-4 inhibitors) or gliptins.

It's used to treat type 2 diabetes, which is caused by problems with a hormone in your body called insulin.

Gliptins help your body make more insulin. They also stop your body releasing too much sugar (glucose) into your blood.

Both of these things help keep your blood sugar levels stable.

How long does it take to work?

Sitagliptin starts to work within a few hours.

You need to take it every day to make sure your blood sugar stays as stable as possible.

How long will I take sitagliptin for? Can I come off it?

Sitagliptin helps keep your blood sugar level as normal as possible to prevent health problems.

You'll probably have to take it for a long time, even for the rest of your life.

Over time it gets harder to control blood sugar levels, so your doctor might eventually recommend stopping sitagliptin and trying a different treatment.

Do not stop taking sitagliptin without speaking to your doctor.

Does it cause hypoglycaemia ('hypos')?

Sitagliptin does not usually cause low blood sugar (known as hypoglycaemia, or "hypos") when taken on its own.

If you're taking other medicines for diabetes, your doctor may recommend reducing the dose of your other medicines when you start sitagliptin.

This will reduce the risk of hypos.

Is it safe to take long term?

Sitagliptin is safe to take for a long time. There do not seem to be any lasting harmful effects from taking it for many months or even years.

You may have seen news stories linking sitagliptin with pancreatic cancer. But there's no firm evidence that sitagliptin causes cancer.

Are there similar medicines to sitagliptin?

Sitagliptin is a dipeptidylpeptidase-4 inhibitor (DPP-4 inhibitor).

Similar medicines include alogliptin, linagliptin, saxagliptin and vildagliptin.

There are other diabetes medicines that you swallow, such as metformin, gliclazide, glimepiride, pioglitazone, canagliflozin, dapagliflozin and empagliflozin.

Are there different types of diabetes medicines?

There are several medicines that can lower blood sugar levels:

  • metformin
  • sulphonylureas, like gliclazide
  • pioglitazone
  • DPP-4 inhibitors, like sitagliptin
  • SGLT2 inhibitors, like dapagliflozin
  • GLP-1 agonists, like exenatide (given by injection)
  • insulin (given by injection)

Your doctor might recommend taking more than one type of diabetes medicine at the same time.

Can I get diabetes medicines for free?

If you have diabetes, you're entitled to free prescriptions for all of your medicines, not just your diabetes ones.

To claim your free prescriptions, you'll need to have a medical exemption certificate (FP92A).

You can get an application form at your GP surgery.

Can I take sitagliptin before surgery?

Yes, you can take sitagliptin before surgery.

Tell your surgeon that you're taking sitagliptin and any other medicines.

Will it affect my contraception?

Sitagliptin does not affect any type of contraception, including the combined pill and emergency contraception.

Will it affect my fertility?

There's no firm evidence to suggest that taking sitagliptin will reduce fertility in either men or women.

But speak to a pharmacist or your doctor if you're trying to get pregnant. They may want to review your treatment.

Can I drink alcohol with it?

Yes, you can drink alcohol while taking sitagliptin.

But it's best to drink no more than 2 units per day. Drinking more than this can increase your risk of low blood sugar.

Try to keep to the recommended guidelines of no more than 14 units of alcohol a week.

A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.

Is there any food or drink I need to avoid?

It's a good idea to cut down on foods with added sugar.

Check the nutrition labels as many foods and drinks are high in sugar, such as:

  • sweets
  • cakes
  • biscuits
  • chocolate
  • some fizzy drinks
  • juice drinks
Will it make me lose weight?

Sitagliptin does not usually make people lose weight or put on any weight.

Can I drive or ride a bike?

If your blood sugar levels are stable, taking sitagliptin should not affect your ability to drive, cycle or use machinery and tools.

If your blood sugar levels become too low, this can reduce your concentration.

If this happens to you, do not drive, cycle or use machines or tools until you feel better.

Can lifestyle changes help?

There are some lifestyle changes you can make to help control the symptoms of diabetes.

These include:

Sitagliptin is usually prescribed when diet and exercise alone have not been enough to control your blood sugar levels.