Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
hearing loss, or a roaring sound in your ears;
severe or ongoing dizziness;
weak or shallow breathing;
numbness or tingly feeling;
twitching, muscle tightness or contraction;
seizure (convulsions);
severe stomach pain, diarrhea that is watery or bloody;
fever, blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;
kidney problems--little or no urinating; painful or difficult urination; swelling in your feet or ankles; feeling tired or short of breath;
signs of an electrolyte imbalance--confusion, weakness, bone pain, increased urination; or
increased pressure inside the skull--severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes.
Side effects may be more likely in older adults.
Common side effects may include:
vision problems;
nausea, vomiting, loss of appetite, weight loss;
a light-headed feeling, like you might pass out;
itching or rash;
pain where the medicine was injected;
headache, mood changes; or
joint pain.
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.
 Gentamicin side effects (more detail)
