Stop using Levoxyl and obtain emergency medical assistance if you have any of these signs of an allergic reaction: hives, difficulty breathing, swelling of the face, lips, tongue, or throat. Call your doctor immediately if you have any of these serious side effects:

• headache;
• sleep problems (insomnia);
• nervous or irritable feeling;
• fever, hot flashes, sweating;
• changes in your menstrual periods;
• changes in appetite, weight changes;

Less serious side effects May include mild hair loss.

This is not a complete list of side effects and others occur in May Talk to your doctor about any unusual or bothersome side effect.