BMA Concise Guide to Medicine & Drugs


Brand names Oxactin, Prozac, Prozep

Used in the following combined preparations None


Drug group Antidepressant drug

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic Yes


Fluoxetine belongs to the group of antidepressants called selective serotonin re-uptake inhibitors (SSRIs). These drugs tend to cause less sedation, have different side effects, and are safer if taken in overdose than older antidepressants. Fluoxetine elevates mood, increases physical activity, and restores interest in everyday pursuits. Fluoxetine is broken down slowly and remains in the body for several weeks after treatment is stopped. The drug is used to treat depression, to reduce binge eating and purging activity (bulimia nervosa), and to treat obsessive-compulsive disorder.


Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Capsules, liquid.

Frequency and timing of doses Once daily in the morning.

Adult dosage range 20–60mg daily.

Onset of effect Some benefits may appear in 14 days, but full benefits may not be felt for 6 weeks or more. Obsessive-compulsive disorder and bulimia may take longer to respond.

Duration of action Beneficial effects may last for up to 6 weeks following prolonged treatment. Adverse effects may wear off within 1–2 weeks.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 8 hours, take a single dose now and skip the next.

Stopping the drug Do not stop the drug without consulting your doctor, who may supervise a gradual reduction in dosage.

Exceeding the dose An occasional unintentional extra dose is unlikely to cause problems. Large overdoses may cause adverse effects. Notify your doctor.


The most common adverse effects of fluoxetine are restlessness, anxiety, insomnia, nausea, vomiting, and headache. Rarely, it may cause sexual dysfunction. Discuss with your doctor if any of these symptoms are severe. If a rash develops or there are suicidal thoughts or attempts, the drug should be stopped and medical advice sought at once.


Sedatives All drugs having a sedative effect may increase the sedative effects of fluoxetine.

Monoamine oxidase inhibitors (MAOIs) Fluoxetine should not be started less than 14 days after stopping an MAOI (except moclobemide) as serious adverse effects can occur. An MAOI should not be started less than 5 weeks after stopping fluoxetine.

Tricyclic antidepressants Fluoxetine reduces the breakdown of tricyclics and may increase the toxicity of these drugs.

Antipsychotics The levels and effects of some of these drugs can be increased by fluoxetine.


Be sure to tell your doctor if:

· You have long-term liver or kidney problems.

· You have a history of mania.

· You have diabetes.

· You have had epileptic seizures.

· You have previously had an allergic reaction to fluoxetine or other SSRIs.

· You are taking other medicines.

Pregnancy Avoid if possible. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk. Discuss with your doctor.

Infants and children Not generally recommended under 18 years.

Over 60 Reduced dose may be necessary.

Driving and hazardous work Avoid such activities until you have learned how fluoxetine affects you because the drug can cause drowsiness and can affect your judgement and coordination.

Alcohol No special problems.


No problems expected in adults. Side effects tend to decrease with time. There is a small risk of suicidal thoughts and self-harm in children and adolescents, although the drug is rarely used for this age group.

Monitoring Any person experiencing drowsiness, confusion, muscle cramps, or seizures should be monitored for low sodium levels in the blood. Under-18s should be monitored for suicidal thoughts and self-harm.