Janumet tablets contain two active ingredients, metformin and sitagliptin. These are both medicines used to help control blood sugar levels in people with type 2 diabetes.
What is Janumet used for?
- Type 2 diabetes.
Janumet tablets are licensed for use in people with type 2 diabetes whose blood sugar is not controlled by the maximum tolerated dose of metformin alone, or who are already taking metformin and sitagliptin as separate tablets.
They are also licensed for use in combination with a sulphonylurea (eg gliclazide) or a glitazone (eg pioglitazone), when one of these combined with metformin has not controlled blood sugar well enough. Janumet tablets may also be used in combination with insulin.
How does Janumet work?
- Janumet tablets contain two active ingredients, metformin and sitagliptin.
- Metformin is a type of antidiabetic medicine known as a biguanide. It works in a number of ways to decrease the amount of sugar in the blood. Firstly, it reduces the amount of sugar produced by cells in the liver. Secondly, it increases the sensitivity of muscle cells to insulin. This enables these cells to remove sugar from the blood more effectively. Finally, it also delays absorption of sugar from the intestines into the bloodstream after eating.
- Sitagliptin is a type of antidiabetic medicine known as a dipeptidyl peptidase-4 (DPP-4) inhibitor. It helps to reduce blood sugar levels by preventing the breakdown of two incretin hormones, called glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). These hormones are normally produced naturally by the body in response to food intake. They stimulate the pancreas to produce insulin in response to increasing levels of glucose in the blood, and they also reduce the production of glucagon, which is a hormone that normally increases glucose production by the liver. These actions help control blood sugar levels.
- This combination of medicines helps control blood sugar levels both directly after meals and between meals.
How do I take Janumet?
- Janumet tablets are usually taken twice a day, morning and evening.
- The tablets should be taken with a meal.
- If you forget to take a dose of this medicine, take it with your next meal, unless you were due to take a tablet then anyway. Do not take a double dose to make up for a forgotten tablet.
Who should not take Janumet?
- People with type 1 diabetes.
- People with diabetic keto-acidosis (due to severe and inadequately treated diabetes).
- People with moderate to severely decreased kidney function.
- People with liver problems.
- People with acute heart failure or who have recently had a heart attack.
- People with conditions that cause breathing to be ineffective, ie to not effectively oxygenate the blood or remove carbon dioxide from the lungs (respiratory failure).
- People with reduced blood flow to vital internal organs (shock).
- People with severe infections or blood poisoning (sepsis).
- People who are dehydrated.
- People who drink large amounts of alcohol or who suffer from alcoholism.
- Women who are pregnant or breastfeeding.
- Janumet is not recommended for children and adolescents under 18 years of age, because its safety and effectiveness have not been established in this age group.
- Janumet should not be used if you are allergic to any of its ingredients. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Can I take Janumet while pregnant or breastfeeding?
- The safety of sitagliptin for use during pregnancy has not been established. It should not be used during pregnancy. Diabetes mellitus is usually controlled using insulin during pregnancy, because this provides a more stable control of blood sugar. Metformin many also sometimes be used. However, as Janumet contains a combination of metformin and sitagliptin it should not be used during pregnancy.
- If you get pregnant while taking Janumet, or want to plan a pregnancy, you should seek medical advice from your doctor.
- It is not known if sitagliptin passes into breast milk. Metformin does pass into breast milk. The manufacturer states that Janumet should not be used by breastfeeding mothers. Seek further medical advice from your doctor.
What are the possible side effects of Janumet?
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with Janumet. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Disturbances of the gut such as nausea, vomiting or abdominal pain, constipation, flatulence and diarrhoea.
- Metallic taste.
- Loss of appetite.
- Swelling of feet or ankles (peripheral oedema).
- Upper respiratory tract infection.
- Inflammation of the nose and throat, causing a blocked or runny nose and sore throat (nasopharyngitis).
- Dry mouth.
- Low blood sugar levels (hypoglycaemia - when used with a sulphonylurea or insulin). See warning section above.
- Skin reactions, such as redness, itching or rash.
- Elevated levels of lactic acid in the blood (lactic acidosis).
- Decreased absorption of vitamin B12 during long-term use.
- Inflammation of the liver (hepatitis).
- Inflammation of the pancreas (acute pancreatitis).
- Inflammation of blood vessels (vasculitis).
- Severe blistering skin reaction affecting the tissues of the eyes, mouth, throat and genitals (Stevens-Johnson Syndrome).
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. Other side effects have been reported with both metformin and sitagliptin used on their own and are therefore possible with this combination product. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
Can I take other medicines with Janumet?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
When Janumet is taken with other antidiabetic medicines, such as sulphonylureas (eg gliclazide, glibenclamide) or insulin, there will be an enhanced blood sugar lowering effect. Your blood sugar level may need to be monitored if you are taking Janumet in combination with other antidiabetic medicines. Ask your doctor for advice.
Cimetidine and rilpivirine may increase the blood level of metformin, which could increase the risk of its side effects. Your doctor may need to reduce your dose of this medicine if you regularly take one of these medicines as well.
Medicines that increase blood sugar levels as a side effect may make this medicine less effective at controlling blood sugar. Medicines that can increase blood sugar levels include the following:
- antipsychotic medicines, such as chlorpromazine, olanzapine, risperidone
- beta-2-agonists, such as salbutamol, salmeterol
- corticosteroids, such as prednisolone
- oestrogens and progestogens, such as those contained in oral contraceptives
- thiazide diuretics, such as bendroflumethiazide.
Your doctor may want to monitor your blood sugar if you start or stop treatment with any of these while taking this medicine, and if necessary your doctor may alter your dose of this medicine.
Low blood sugar levels (hypoglycaemia) may occur, sometimes unpredictably, if disopyramide or ACE inhibitors such as captopril are taken with this medicine. Your doctor may want you to temporarily check your blood sugar more frequently if you start treatment with one of these while taking this medicine.
MAOI antidepressants, such as phenelzine, tranylcypromine or isocarboxazid, may enhance the blood sugar lowering effect of metformin. Your doctor may ask you to monitor your blood sugar more frequently if you are prescribed an MAOI antidepressant with this medicine.
A drop in the number of blood cells called platelets in the blood has been seen in some people taking the antihistamine ketotifen in combination with metformin. The manufacturer of ketotifen recommends that it should be avoided in people taking metformin.
Sitagliptin may cause a small increase in the amount of digoxin in the blood when both medicines are being taken together. If you are taking digoxin, your doctor may want you to have regular blood tests to monitor the amount of digoxin in your blood after you start treatment with this medicine.
If you have any more questions please ask your Pharmacist.
Remember to keep all medicines out of reach of children
Please Note: We have made every effort to ensure that the content of this information sheet is correct at time of publish, but remember that information about drugs may change. This sheet does not list all the uses and side-effects associated with this drug. For full details please see the drug information leaflet which comes with your medicine. Your doctor will assess your medical circumstances and draw your attention to any information or side-effects which may be relevant in your particular case.