Januvia: what it is used for, dosage and side effects

What Januvia is and which active substance it contains

Januvia contains sitagliptin, an active substance from the group of dipeptidyl peptidase-4 inhibitors, usually shortened to DPP-4 inhibitors. In the Maltese register of medicines it is recorded with sitagliptin as its active substance and the oral route of administration. It is a tablet, it is not insulin and it is not injected.

Sitagliptin appears on the same register under a considerable number of other names, both as a single substance and in fixed combination with metformin hydrochloride, of which Janumet is the best known example. This is a practical warning rather than a curiosity: if you already take a combination tablet containing sitagliptin, adding plain Januvia on top of it means taking the same substance twice. Check the composition printed on the pack rather than trusting the name, and ask a pharmacist when two packs look unfamiliar.

Sitagliptin was authorised for the whole European Union through the central procedure, so the European Medicines Agency publishes the full product information, and the leaflet in your pack carries the same content in shorter form. Read that leaflet before starting a new pack, because wording on warnings and interactions is revised from time to time and the version in your hand may be older than the one published online. Authorised products in Malta and their product information are listed by the Medicines Authority.

The authorised indications for your own product are set out in that product information. The groups of medicines used in type 2 diabetes and how they differ are compared at /diabetes-and-blood-sugar/, and how the disease presents is described at /health-guide/type-2-diabetes-symptoms/.

What it is used for

Sitagliptin is used in type 2 diabetes to bring blood sugar towards target, on its own where metformin cannot be used, or in combination with metformin, with an SGLT2 inhibitor, with a sulfonylurea or with insulin. The combination with metformin is by far the most common, which is why a fixed-dose tablet containing both exists on the register.

Which medicine is added, and in what order, is a decision for the doctor, taken on your test results, your kidney function, your weight and your other conditions rather than on a single blood sugar reading. Gliptins are generally chosen where a low risk of hypoglycaemia and a neutral effect on weight matter, but that trade-off is a clinical judgement and not a preference to be made from a website.

The medicine does not replace diet and physical activity, and it does not remove the need for the regular checks that belong to the disease. Type 2 diabetes very often produces no symptoms at all for years, so treatment is assessed on measurements: feeling well is not evidence that blood sugar is where it should be.

How sitagliptin works

When food reaches the gut, the gut releases hormones known as incretins, which tell the pancreas to release insulin and at the same time damp down the release of glucagon, the hormone that raises blood sugar. These incretins are broken down quickly by an enzyme called DPP-4, so their effect is short-lived by nature.

Sitagliptin blocks that enzyme. The body's own incretins therefore survive longer and their effect lasts longer, so more insulin is released after a meal and less glucagon is released between meals. The important detail is that this whole system is driven by food: the effect appears when blood sugar rises and fades when it does not.

That glucose dependence is why sitagliptin taken on its own rarely causes hypoglycaemia and why it is broadly neutral for body weight. The risk of a low blood sugar appears in combination with insulin or with a sulfonylurea, and in those combinations the doctor usually reduces the dose of the other medicine rather than the sitagliptin.

The substance is largely removed from the body by the kidneys, which is why kidney function sets the dose, why the doctor rechecks it and why a fall in kidney function is a reason to review the prescription rather than to continue unchanged. The effect on blood sugar builds up over weeks and is judged from HbA1c compared with the result before treatment.

How it is taken and what to watch for

The dose is set by the doctor and written in the leaflet supplied with your pack; the tablet is taken once a day, with or without food, and swallowed whole. Where kidney function is reduced the dose is lower, and the figure that applies to you comes from your own results and your own product information rather than from a general table.

The medicine is not used where there is hypersensitivity to sitagliptin or to any of the excipients in your pack. Particular care and a decision by the doctor are needed where there is a history of inflammation of the pancreas, where there are gallstones, where alcohol intake is high, where you have heart failure and where kidney function is reduced. Type 1 diabetes and diabetic ketoacidosis are not conditions this medicine is intended for.

Two warnings deserve to be stated plainly rather than softened. Inflammation of the pancreas has been reported with this group: severe, persistent pain in the upper abdomen that may spread to the back, with nausea and vomiting, means stopping the medicine and seeking urgent medical help. Severe and persistent joint pain has also been reported, and it is a reason to contact the doctor rather than to wait it out, because it can settle when the medicine is stopped.

Bullous pemphigoid, a blistering skin condition, has been described with this group as well; blisters or erosions of the skin are a reason for medical assessment. In pregnancy, when planning a pregnancy and while breastfeeding, the treatment is reviewed by the doctor. Do not stop the medicine on your own initiative because the result has come to target, since the result reflects the treatment.

Interactions with other medicines

Sitagliptin has fewer clinically important interactions than several other groups used in diabetes, and that is one of the reasons it is often chosen for patients who already take a long list of medicines. It does not follow that the list stops mattering.

The interaction that matters most is with medicines that themselves lower blood sugar. With insulin and with sulfonylureas the risk of hypoglycaemia rises, and the doctor usually lowers the dose of those rather than of the sitagliptin. Recognising a low blood sugar, and knowing what to do about it, is part of treatment in those combinations.

Care is needed with digoxin, whose level can rise slightly, and with medicines that reduce kidney function, including non-steroidal anti-inflammatory medicines and some blood pressure medicines, because kidney function governs the dose of this one. Where several of those are taken together during an illness with vomiting or diarrhoea, the doctor may want kidney function rechecked.

List for your doctor and your pharmacist everything you take, including medicines bought without a prescription, food supplements and herbal products. A single review of the full list is more useful than checking one item at a time.

Side effects and when to seek help

The medicine is generally well tolerated. The effects described most often are headache, symptoms of an upper respiratory infection, inflammation of the nose and throat, and digestive complaints such as nausea, abdominal pain, constipation or diarrhoea. Low blood sugar appears mainly in combination with insulin or a sulfonylurea rather than with sitagliptin alone.

Less often, dizziness, itching, rash and swelling of the ankles are reported, the last of these particularly in combination with certain other diabetes medicines. Changes in blood test results, including kidney function tests, are also described.

Rare but serious events include inflammation of the pancreas, severe hypersensitivity reactions with swelling of the face, lips or tongue, severe skin reactions, bullous pemphigoid with blistering of the skin, and severe joint pain. Seek urgent medical help for severe and persistent upper abdominal pain, for persistent vomiting, for swelling of the face or tongue with difficulty breathing, or for a widespread blistering rash, and call 112 in a life-threatening situation.

The complete list of side effects with information on how often each occurs is in the leaflet supplied with your pack and in the product information published by the European Medicines Agency. A suspected side effect can be reported to your doctor or pharmacist, and safety of medicines on the Maltese market is monitored by the Medicines Authority.

Prescription status and what we can do

Januvia is a prescription-only medicine in Malta, so the decision to start it and the dose belong to a doctor. We do not sell medicines and we cannot send you one. What we offer is a written medical questionnaire and a doctor review of your answers. There is no video call, no telephone consultation and no live chat.

We are not part of any Maltese state health record and we write nothing into one. The doctor issues a cross-border prescription in the format set out in the Annex to Directive 2012/52/EU, which reaches you as a PDF by e-mail. You print it or show it on screen at the pharmacy, together with a photo identity document. There is no code and no number to quote, and a pharmacy in Malta may dispense it; the decision rests with the pharmacist, who can refuse if the document is illegible or if its authenticity is in doubt.

If sitagliptin has already been started for you and this is a continuation of established treatment, you can fill in the questionnaire at /repeat-prescription/. The review is carried out by lek. Damian Wojno, a doctor registered with the Polish Medical Chamber, licence no. 3211301; he is not registered with the Medical Council of Malta. A recent HbA1c and a recent measure of kidney function are the results the doctor asks for most often, because the dose depends on the second of them. We do not start this treatment for the first time from a questionnaire, and we do not deal this way with the warning signs described above.

The assessment costs 24,90 €, with an optional priority surcharge of 9,90 €. The fee covers the medical consultation, not the issuing of a document, and it is not funded by the Maltese public health system. If the doctor declines on medical or legal grounds, we refund the fee. If the doctor asks for documents, you have at least seven days to send them in, and if the consultation cannot be completed, we close the request and refund the fee in full. The medicine itself is paid for separately at the pharmacy; what the fee does and does not cover is set out at /blog/online-prescription-cost-malta/.