Minor Side Effects

• There are several minor side effects that could occur from Cymbalta use. These side effects usually go away very quickly after starting the medication. However, if the side effects persist, or even get worse, you should notify your physician. These side effects include changes in weight, mild gas, constipation, nausea, blurry vision, dry mouth, sleeplessness, muscle or joint ache, impotence, problems with orgasm, lowered sex drive, dizziness, the sensation of spinning and drowsiness.
  
  

Severe Side Effects

• In situations of severe side effects, it is crucial to seek medical attention immediately. Some possibly dangerous Cymbalta side effects include bloody, tarry or black stools; stomach ache; nausea; clay-colored stools; darker-colored urine; appetite loss; extremely stiff muscles; unsteadiness; weakness; coordination loss; difficulty concentrating; high fever; throwing up; sweating; uneven or rapid heartbeat; diarrhea; confusion; painful urination; hallucinations; problems with memory; easy bleeding or bruising; jaundice; nosebleeds; seizure; passing out; breathing that ceases; and shallow breathing.
  
  

Allergic Reactions

• Though rather uncommon, allergic reactions to Cymbalta can occur, and require immediate emergency medical assistance. Some signs of allergic reaction to the medicine are hives, skin rash, and swelling of the tongue, throat, lips or face.
  
  

Emotional and Behavioral Side Effects

• If you develop any new emotional or behavioral side effects (or if the emotional or behavioral side effects you already experience get even worse), you should notify your doctor. These severe emotional side effects include panic attacks, changes in behavior, agitation, irritability, hostility, aggression, impulsiveness, hyperactivity, restlessness and suicidal thoughts.
  
  

Overdose

• If you are worried that you've taken too much Cymbalta, you run the risk of possibly having overdosed. Overdosing on Cymbalta calls for immediate emergency help. Some signs to look for include hallucinations, rapid heart rate, throwing up, nausea, diarrhea, lightheadedness, passing out, confusion and agitation.