Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Janumet. If you are concerned about side effects, discuss the risks and benefits of Janumet with your doctor.

The following side effects have been reported by at least 1% of people taking Janumet. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• back pain
• bloating
• Constipation
• Diarrhea
• headache
• itching
• joint or muscle pain
• loss of appetite
• metallic taste in mouth
• nausea
• passing of gas
• sore throat
• stomach upset
• stuffy or runny nose
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blisters
• signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of kidney failure (e.g., decreased urine production, swelling, fatigue, abdominal pain, nausea, loss of appetite)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• symptoms of mildly low blood sugar (e.g., anxiety, difficulty concentrating, nausea, cold sweat, cool pale skin, headache, fast heartbeat, weakness, shakiness)
• symptoms of decreased Thyroid function (e.g., weight gain, feeling cold, fatigue)
• tingling and numbness of feet or hands

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of lactic acidosis (e.g., nausea, vomiting, increased breathing rate, abdominal pain, unusual tiredness, dizziness, rapid heart rate, muscle pain or cramping, feeling cold)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, Fever, chills, rapid heartbeat, swollen abdomen)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• symptoms of a Anaphylaxis (severe allergic reaction) (e.g., Hives, difficulty breathing or swallowing, swelling of the face, lips, tongue, or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Janumet.

50 mg/500 mg
Each light pink, capsule-shaped, film-coated tablet with "575" debossed on one side contains 64.25 mg of sitagliptin phosphate monohydrate, equivalent to 50 mg of sitagliptin as free base, and 500 mg of metformin hydrochloride. Nonmedicinal ingredients: microcrystalline cellulose, polyvinylpyrrolidone, sodium lauryl sulfate, and sodium stearyl fumarate; film coating: black iron oxide, polyvinyl alcohol, polyethylene glycol, red iron oxide, talc, and titanium dioxide.

50 mg/850 mg
Each pink, capsule-shaped, film-coated tablet with "515" debossed on one side contains 64.25 mg of sitagliptin phosphate monohydrate, equivalent to 50 mg of sitagliptin as free base, and 850 mg of metformin hydrochloride. Nonmedicinal ingredients: microcrystalline cellulose, polyvinylpyrrolidone, sodium lauryl sulfate, and sodium stearyl fumarate; film coating: black iron oxide, polyvinyl alcohol, polyethylene glycol, red iron oxide, talc, and titanium dioxide.

50 mg/1000 mg
Each red, capsule-shaped, film-coated tablet with "577" debossed on one side contains 64.25 mg of sitagliptin phosphate monohydrate, equivalent to 50 mg of sitagliptin as free base, and 1000 mg of metformin hydrochloride. Nonmedicinal ingredients: microcrystalline cellulose, polyvinylpyrrolidone, sodium lauryl sulfate, and sodium stearyl fumarate; film coating: black iron oxide, polyvinyl alcohol, polyethylene glycol, red iron oxide, talc, and titanium dioxide.

Do not take sitagliptin - metformin if you:

• are allergic to sitagliptin, metformin, or any ingredients of the medication
• are breast-feeding
• are pregnant or planning to become pregnant
• are undergoing radiologic studies involving use of iodinated contrast materials
• are severely dehydrated
• drink a lot of alcohol in a short term or on a regular basis
• have cardiovascular collapse (sudden failure of blood circulation) or cardio-respiratory insufficiency (reduced oxygen supply to tissues)
• have metabolic acidosis (including diabetic ketoacidosis) or a history of ketoacidosis or lactic acidosis (too much acid in the blood)
• have or are recovering from a severe infection, trauma, or surgery
• have poor blood glucose control or insulin-dependent (Type 1) diabetes mellitus
• have reduced kidney function or Kidney Disease
• have severely reduced liver function or liver disease

There may be an interaction between sitagliptin - metformin and any of the following:

• Acetazolamide
• alcohol
• Amiodarone
• angiotensin converting enzyme inhibitors (ACEIs; Captopril, Enalapril, Ramipril)
• antipsychotics (e.g., Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• β2-agonists (e.g., salbutamol, formoterol)
• birth control pills
• calcium channel blockers (e.g., Amlodipine, Diltiazem, Nifedipine, Verapamil)
• Carbamazepine
• Carvedilol
• Cephalexin
• Cimetidine
• Cobicistat
• inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
• oral corticosteroids (e.g., Dexamethasone, Hydrocortisone, Prednisone)
• Crizotinib
• Cyclosporine
• Cyproterone
• Danazol
• other diabetes medications (e.g., chlorpropamide, Glyburide, insulin, metformin, Rosiglitazone)
• Digoxin
• Dipyridamole
• Disopyramide
• diuretics (water pills; e.g., Hydrochlorothiazide, Furosemide, Amiloride, triamterene)
• dofetilide
• dolutegravir
• Dronedarone
• estrogens (e.g., conjugated estrogen, Estradiol, ethinyl estradiol)
• Everolimus
• Goserelin
• Glucagon
• glycopyrrolate
• grapefruit juice
• Hepatitis C antivirals (e.g., ombitasvir, paritaprevir, ritonavir, dasabuvir,
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• iodinated contrast material
• isoniazid
• itraconazole
• Lamotrigine
• Lanreotide
• Leuprolide
• Lomitapide
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• Mefloquine
• mifepristone
• monoamine oxidase inhibitors (M.O.S. e.g., Moclobemide, Phenelzine, Rasagiline, Selegiline, Tranylcypromine)
• nefazodone
• nicotinic acid
• Nilotinib
• Octreotide
• Ondansetron
• Pasireotide
• Phenytoin
• Prazosin
• progestins (e.g., Dienogest, Levonorgestrel, medroxyprogesterone, Norethindrone)
• quinidine
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, levofloxacin, moxifloxacin)
• Ranitidine
• rifampin
• St. John's wort
• salicylates (e.g., Asa)
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
• Somatropin
• "statin" anticholesterol medications (e.g., Atorvastatin, Lovastatin, Simvastatin)
• sulfonamides (e.g., sulfamethoxazole)
• Sunitinib
• Tacrolimus
• testosterone
• thyroid replacements (e.g., desiccated thyroid, Levothyroxine)
• Topiramate
• Trimethoprim
• Vorinostat

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Janumet. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Janumet.

Alcohol intake: Large amounts of alcohol or regular use of alcohol increases the risk of developing lactic acidosis when taking metformin. People taking Janumet should avoid excessive alcohol intake.

Blood glucose control: People taking Janumet who have a fever, experience trauma, or have surgery may experience a temporary loss of blood glucose control. At such times, it may be necessary to stop Janumet and temporarily inject insulin. Janumet may be started again after the problem is resolved.

Congestive Heart Failure (CHF): Congestive heart failure can increase the risk of lactic acidosis caused by metformin. For this reason, Janumet is not recommended for people with CHF. If you have CHF, speak to your doctor.

Diabetes complications: The use of Janumet will not prevent the development of complications of diabetes mellitus (e.g., kidney disease, nerve disease, eye disease).

Dye or contrast agents: If you are going to have an X-ray procedure that uses dye or a contrast agent, you may need to stop taking Janumet for a short time. Contact your doctor for instructions.

Hypersensitivity reaction: A severe allergic reaction called a hypersensitivity reaction has occurred for some people with the use of sitagliptin. Stop taking the medication and get immediate medical attention if you have symptoms of a severe allergic reaction, including fever, swollen glands, yellowing of the skin or eyes, or flu-like symptoms with skin rash or blistering.

Kidney function: Kidney disease or reduced kidney function may cause metformin or sitagliptin to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how Janumet may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Janumet, and whether any special monitoring is needed.

Sitagliptin may cause decreased kidney function, including kidney failure. Your doctor may recommend regular testing to check your kidney function while you are taking Janumet. Janumet is not recommended for people with reduced kidney function.

Lactic acidosis: Lactic acidosis is a rare but serious problem that occurs due to metformin accumulation (i.e., the body doesn't get rid of the medication fast enough) during treatment. People with severe kidney disease, heart failure, or dehydration are at higher risk of developing lactic acidosis. Since alcohol may increase the risk of lactic acidosis, do not drink a lot of alcohol over the short or long term while taking Janumet. When it does occur (very rarely), it is fatal in 50% of cases. If you experience symptoms of lactic acidosis (e.g., weakness; tiredness; drowsiness; unusual muscle pain; trouble breathing; stomach pain with nausea, vomiting, or diarrhea; feeling cold; dizziness; lightheadedness; slow or irregular heartbeat), stop taking Janumet and get immediate medical attention.

Liver function: Janumet is not recommended for people with severely reduced liver function. If you have moderately reduced liver function, discuss with your doctor how Janumet may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Janumet, and whether any special monitoring is needed.

Low blood glucose: Low blood glucose can occur when sitagliptin – metformin is used in combination with other medications to treat diabetes. Low blood glucose may also occur when not enough food is eaten, especially when strenuous exercise is undertaken at the same time or when large amounts of alcohol have been consumed. If you experience low blood sugar (e.g., headache, drowsiness, weakness, dizziness, confusion, irritability, hunger, fast heartbeat, sweating, and feeling jittery) while taking Janumet, contact your doctor.

Pancreatitis: Janumet may cause pancreatitis (inflammation of the pancreas). If you have a history of pancreatitis, gallstones, Alcoholism, or high triglycerides you may be more at risk of experiencing this. If you experience prolonged and severe abdominal pain with or without vomiting while taking Janumet, contact your doctor immediately.

Reduced response: Over a period of time, people may become progressively less responsive to a particular treatment for diabetes because their diabetes worsens. If your blood glucose control worsens or you are not staying within your target levels, talk to your doctor.

Surgery: Janumet should be stopped temporarily for surgery (except for minor surgery where food and fluid intake is not restricted). You will be restarted on Janumet once you are eating and drinking and your kidney function has been tested and is normal. Talk to your doctor for specific instructions.

Thyroid function: People with low thyroid function may develop further decreases in the function of their thyroid. Symptoms of these changes include feeling cold all the time, weight gain, fatigue, dry skin, and decreased memory and concentration. Contact your doctor if you experience these symptoms.

Vitamin B12 levels: Janumet may decrease vitamin B12 levels. Your doctor will monitor your B12 levels with blood tests while you are taking Janumet.

Pregnancy: Janumet is not recommended for use during pregnancy or for women who are planning to become pregnant. If you become pregnant while taking Janumet, contact your doctor immediately. Insulin is usually used during pregnancy to control blood glucose levels.

Breast-feeding: It is not known if sitagliptin passes into breast milk. Metformin does pass into breast milk. If you are a breast-feeding mother and are taking Janumet, it may affect your baby. Janumet should not be used by women who are breast-feeding.

Children: The safety and effectiveness of Janumet have not been established for children less than 18 years of age.

Seniors: Kidney function often decreases with age. As a result, seniors may be more likely to experience side effects of Janumet.