What side effects may I notice from receiving Metformin Hydrochloride?

Side effects that you should report to your doctor or health care professional as soon as possible:

-allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
-breathing problems
-feeling faint or lightheaded, falls
-muscle aches or pains
-signs and symptoms of low blood sugar such as feeling anxious, confusion, dizziness, increased hunger, unusually weak or tired, sweating, shakiness, cold, irritable, headache, blurred vision, fast heartbeat, loss of consciousness
-slow or irregular heartbeat
-unusual stomach pain or discomfort
-unusually tired or weak

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

-diarrhea
-headache
-heartburn
-metallic taste in mouth
-nausea
-stomach gas, upset

This list may not describe all possible side effects for Metformin Hydrochloride. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.