Get emergency medical help if you have signs of an allergic reaction to Janumet: (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).
Stop taking this medicine and call your doctor right away if you have symptoms of pancreatitis: severe pain in your upper stomach spreading to your back, nausea and vomiting, loss of appetite, or fast heartbeats.
Some people develop lactic acidosis while taking metformin. Early symptoms may get worse over time and this condition can be fatal. Stop taking this medicine and get emergency medical help if you have even mild symptoms such as:
unusual muscle pain;
feeling cold;
trouble breathing;
feeling dizzy, light-headed, tired, or very weak;
stomach pain, nausea with vomiting; or
slow or irregular heartbeat.
Call your doctor at once if you have any of these serious side effects:
itching, blisters, breakdown of the outer layer of skin;
severe or ongoing pain in your joints;
little or no urinating; or
shortness of breath (even while lying down), swelling in your legs or feet, rapid weight gain; or
signs of low blood sugar, including headache, sleepiness, dizziness, sweating, feeling jittery, hunger, or fast heartbeat.
Common Janumet side effects may include:
low blood sugar (if you also use insulin or another oral diabetes medication);
upset stomach, indigestion, gas, diarrhea, nausea, vomiting;
headache, weakness; or
cold symptoms such as runny or stuffy nose, sneezing, sore throat.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Janumet side effects (more detail)
