Sexual Side Effect

• Fluoxetine use is associated with the lack of interest in sexual activity. Fortunately, lack of interest in sexual activity is not a serious side effect and does not require immediate medical attention. It is important that you discuss this reaction with your doctor.
  
  

Sexual Performance

• Fluoxetine is additionally associated with another side effect--difficulty with sexual performance. Fluoxetine may cause an inability to achieve or sustain an erection, or it may cause the user to have difficulty achieving climax.
  
  

Severe Side Effects

• Fluoxetine can be associated with life-threatening side effects. Severe Fluoxetine reactions include skin rash, hives, breathing difficulties, facial swelling (lips, tongue, throat or neck). Other severe reactions include mood changes, anxiety, panic attacks, difficulty sleeping, irritability, agitation, aggressive or restless behavior, hyperactivity (both mental and physical), deeper depressive symptoms, or thoughts of harming yourself, suicide, or hurting others.
  
  

Moderate Side Effects

• In addition to lack of sexual interest, impotence or an inability to achieve orgasm, other side effects of Fluoxetine include blistering or peeling skin rash, stiff muscles, fever, sweating, rapid heart rate, nausea or vomiting, diarrhea, appetite loss, headache, difficulty concentrating, feeling weak or confused, hallucinating, fainting, seizure or convulsions.
  
  

Less Severe Side Effects

• Less severe side effects of Fluoxetine include cold-like symptoms such as sneezing, stuffy or runny nose, sore throat, feeling drowsy or dizzy, nervousness, feeling mildly nauseous, stomach upset or feeling constipated, increase in appetite, fluctuating weight (gain or loss), and difficulty sleeping.