Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Less common
Chest pain or discomfort
decreased urine output
difficult or labored breathing
difficulty with swallowing
dilated neck veins
extreme fatigue
fainting
fast, slow, irregular, pounding, or racing heartbeat or pulse
fever
heat intolerance
hives or welts, skin itching, rash, or redness
irregular breathing
irritability
menstrual changes
nausea
pain or discomfort in the arms, jaw, back, or neck
sweating
swelling of the eyes, face, lips, throat, or tongue
tightness in the chest
tremors
Rare
Blurred or double vision
dizziness
eye pain
lack or slowing of normal growth in children
limp or walk favoring one leg
pain in the hip or knee
seizures
severe headache
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Change in consciousness
cold, clammy skin
confusion
disorientation
fast or weak pulse
lightheadedness
loss of consciousness
sudden headache
sudden loss of coordination
sudden slurring of speech
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Abdominal or stomach cramps
change in appetite
crying
diarrhea
false or unusual sense of well-being
fear or nervousness
feeling not well or unhappy
feeling of discomfort
feeling of warmth
feeling things are not real
feelings of suspicion and distrust
hair loss
headache
increased appetite
mental depression
muscle weakness
quick to react or overreact emotionally
rapidly changing moods
redness of the face, neck, arms, and occasionally, upper chest
restlessness
trouble getting pregnant
trouble sitting still
unusual tiredness or weakness
vomiting
weight gain or loss
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
 Unithroid side effects (more detail)
