Get emergency medical help if you have any of these signs of an allergic reaction to penicillin V: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:
diarrhea that is watery or bloody;
fever, chills, body aches, flu symptoms;
easy bruising or bleeding, unusual weakness;
urinating less than usual or not at all;
severe skin rash, itching, or peeling;
agitation, confusion, unusual thoughts or behavior; or
seizure (black-out or convulsions).
Less serious penicillin V side effects are more likely to occur, such as:
nausea, vomiting, stomach pain;
vaginal itching or discharge;
headache;
swollen, black, or "hairy" tongue; or
thrush (white patches or inside your mouth or 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.
 Penicillin v potassium side effects (more detail)
