It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood and urine tests may be needed to check for unwanted effects.
Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
Do not use this medicine if you are also taking any of the following medicines: boceprevir (Victrelis®), cyclosporine (Gengraf®, Neoral®, Sandimmune®), danazol (Danocrine®), gemfibrozil (Lopid®), nefazodone (Serzone®), telaprevir (Incivek®), certain antibiotics (such as clarithromycin, erythromycin, itraconazole, ketoconazole, posaconazole, telithromycin, voriconazole, Nizoral®), or medicines to treat HIV/AIDS (such as atazanavir, indinavir, nelfinavir, ritonavir, saquinavir, tipranavir, Crixivan®, Kaletra®, Lexiva®, Norvir®, Prezista®, Reyataz®). Using these medicines together with sitagliptin and simvastatin combination may increase your risk of muscle injury and could result in kidney problems.
Chinese patients who are taking large amounts of niacin (greater than or equal to 1 gram or 1000 milligrams per day) together with this medicine may have an increased risk for muscle injury. Talk to your doctor if you are Chinese or have Chinese ancestry and take large amounts of niacin (Niacor®, Niaspan®). You may need a different dose of this medicine.
Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness, especially if you also have unusual tiredness or a fever. These could be symptoms of serious muscle problems, such as myopathy or immune-mediated necrotizing myopathy (IMNM). Myopathy is more common when high doses of simvastatin (e.g., 80 milligrams) are used, but some people get myopathy with lower doses.
Call your doctor right away if you have dark-colored urine, diarrhea, a fever, muscle cramps or spasms, muscle pain or stiffness, or unusual tiredness or weakness. These could be symptoms of a serious muscle problem called rhabdomyolysis, which can cause kidney problems.
Call your doctor right away if you have dark-colored urine, a general feeling of tiredness or weakness, a headache, light-colored stools, loss of appetite, stomach pain, upper right stomach pain, vomiting, weight loss, or yellow eyes or skin. These could be symptoms of liver damage.
Stop using this medicine and tell your doctor right away if you have sudden and severe stomach pain, nausea, vomiting, fever, or lightheadedness. These may be symptoms of pancreatitis (swelling and inflammation of the pancreas).
This medicine may cause serious allergic reactions, including anaphylaxis, angioedema, or certain skin conditions (Stevens-Johnson syndrome). These reactions can be life-threatening and require immediate medical attention. Call your doctor right away if you have a rash, itching, blistering, peeling, or loosening of the skin, fever or chills, trouble breathing or swallowing, or any swelling of your hands, face, mouth, or throat while you are using this medicine.
This medicine may cause hypoglycemia (low blood sugar). Low blood sugar can also occur if you delay or miss a meal or snack, exercise more than usual, drink alcohol, cannot eat because of nausea or vomiting, take certain medicines, or take sitagliptin with another type of diabetes medicine (e.g., insulin, glimepiride, metformin, or pioglitazone). Symptoms of low blood sugar must be treated before they cause you to pass out (unconsciousness). People feel different symptoms with low blood sugar. It is important that you learn which symptoms you usually have so you can treat it quickly.
Symptoms of low blood sugar include anxiety, behavior changes similar to being drunk, blurred vision, cold sweats, confusion, cool, pale skin, difficulty with thinking, drowsiness, excessive hunger, a fast heartbeat, headaches that continue, nausea, nervousness, nightmares, restless sleep, shakiness, slurred speech, or unusual tiredness or weakness.
If symptoms of low blood sugar occur, check your blood sugar level. If you have low blood sugar, eat glucose tablets or gel, corn syrup, honey, or sugar cubes; or drink fruit juice, non-diet soft drinks, or sugar dissolved in water. Glucagon is a medicine that is used in emergency situations when severe symptoms, such as seizures (convulsions) or unconsciousness occur. Have a glucagon kit available, along with a syringe and needle, and know how to use it. The members of your family should also know how to use glucagon.
There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says you have diabetes with a list of all your medicines.
Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine if you have major surgery, a major injury, or you develop other serious health problems.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.