Fluoxetine (Fluoxetine 20mg capsules)

Side effects

Information specific to: Fluoxetine 20mg capsules when used in Depression.


A medicine is only made available to the public if the clinical trials have shown that the benefits of taking the medicine outweigh the risks.

Once a medicine has been licensed, information on the medicine's effects, both intended and unintended, is continuously recorded and updated.

Some side-effects may be serious while others may only be a mild inconvenience.

Everyone's reaction to a medicine is different. It is difficult to predict which side-effects you will have from taking a particular medicine, or whether you will have any side-effects at all. The important thing is to tell your prescriber or pharmacist if you are having problems with your medicine.

Very common: More than 1 in 10 people who take Fluoxetine hydrochloride

  • diarrhoea
  • difficulty sleeping
  • headaches
  • nausea
  • tiredness
  • weakness

Common: More than 1 in 100 people who take Fluoxetine hydrochloride

  • bleeding problems in women
  • blurred vision
  • chills
  • concentration problems
  • decreased libido
  • dry mouth
  • ejaculation problems
  • erectile dysfunction
  • feeling anxious
  • feeling dizzy
  • feeling jittery
  • feeling nervous
  • feeling restless
  • feelings of tension
  • flushing
  • hot flushes
  • increased sweating
  • indigestion
  • jointpain
  • lethargy
  • loss of appetite
  • palpitations
  • sedation
  • skin rash or rashes, urticaria, itching - you or your carer must seek medical advice if you get rashes urticaria or itching
  • sleepiness
  • sleeping problems including abnormal dreams or nightmares
  • taste changes
  • tremors
  • urinating more often
  • vomiting
  • weight loss
  • yawning

Uncommon: More than 1 in 1000 people who take Fluoxetine hydrochloride

  • abnormal muscle movements or problems controlling muscle movement
  • abnormal orgasm including inability to have an orgasm
  • abnormal thoughts or feelings
  • balance or coordination problems
  • breathing difficulties
  • cold sweats
  • depersonalisation
  • easy bruising of the skin
  • enlargement of the pupil
  • euphoria
  • feeling cold
  • feeling hot
  • general feeling of being unwell
  • hair loss
  • lowered blood pressure
  • mood changes
  • muscle twitching
  • painful urination
  • psychomotor hyperactivity
  • sexual dysfunction
  • swallowing difficulties
  • teeth grinding

Rare: More than 1 in 10,000 people who take Fluoxetine hydrochloride

  • anaphylactic reactions - you or your carer must seek medical advice if you get anaphylactic reactions
  • angioedema - you or your carer must seek medical advice if you develop angioedema
  • bruising
  • convulsions
  • ECG changes
  • feeling agitated
  • feeling restless and inability to sit still
  • galactorrhoea
  • hallucinations
  • heart problems
  • mania or mania-like behaviour - you or your carer must immediately seek medical advice if you develop symptoms of mania
  • metabolic problems
  • oesophagealpain
  • panic attacks
  • pharyngitis
  • photosensitivity
  • serum sickness
  • tardive dyskinesia
  • unexplained or easy bruising of the skin or mucous membranes
  • urinary retention
  • vasculitis
  • vasodilatation

Very rare: Fewer than 1 in 10,000 people who take Fluoxetine hydrochloride

  • thrombocytopenia

The frequency of these side-effects is unknown

  • abnormal laboratory test results
  • behavioural problems or worsening of behavioural problems such as feelings of hostility, anger, aggression, thoughts of committing suicide or suicidal tendencies - you or your carer must seek medical advice if you have behavioural changes, thoughts of committing suicide or have attempted to commit suicide
  • bleeding from mucous membranes or the skin
  • bleeding gums
  • blood sugar control changes in diabetics
  • bloody stools
  • bone fractures
  • confusion
  • endocrine problems
  • erythema multiforme - this could lead to Stevens-Johnson syndrome or toxic epidermal necrolysis
  • gastrointestinal or rectal bleeding
  • liver problems
  • lung problems
  • melaena
  • memory problems
  • musclepain or tenderness
  • nose bleed
  • other bleeding problems
  • priapism
  • seizures - you or your carer must seek immediate medical advice if you have seizures or if seizures occur more frequently
  • serotonin or neuroleptic malignant-type syndrome - this may be fatal. You or your carer must seek immediate medical help if you get these symptoms: abnormally high body temperature, rigidity, muscle twitches or sudden jerks, mental changes including confusion, irritability, agitation, delirium or coma
  • speech problems
  • tinnitus
  • urinary problems
  • vomitingblood
  • withdrawal symptoms can occur when this medicine is stopped abruptly. These include dizziness, sensory changes such as paraesthesiae, weakness, increased agitation, anxiety, sleeping problems including sleep disturbances or intense dreams, nausea, vomiting, tremors or headaches

The following side-effects have also been reported in children and adolescents who take medicines similar to Fluoxetine hydrochloride. The frequency of these side-effects is unknown

  • delay in the onset of puberty and development of sexual organs
  • feelings of hostility
  • growth suppression or reduced weight gain

If you feel unwell or if you have concerns about a side-effect, you will need to seek advice. If you feel very ill, get medical help straight away. Contact your prescriber, pharmacist, nurse or call 111.

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Before a medicine is granted a licence so that it can be made available in the United Kingdom, it must pass strict tests and checks to ensure that it is acceptably safe and effective. All effective medicines however, can cause side effects.

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