Get emergency medical help if you have signs of an allergic reaction (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 loperamide and call your doctor at once if you have:
diarrhea that is watery or bloody;
stomach pain or bloating;
ongoing or worsening diarrhea; or
fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out).
Common side effects may include:
constipation;
dizziness, drowsiness;
nausea; or
stomach cramps.
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.
 Loperamide side effects (more detail)
