A to Z of MS Fluoxetine (Prozac)

Product name

Prozac. Several non branded versions are also available.

Fluoxetine is one of the class of SSRI (selective serotonin reuptake inhibitor) drugs. It is normally prescribed for depression.

Exploratory studies have also looked at whether fluoxetine might have a role in reducing inflammation around nerves in multiple sclerosis. Although some effect was recorded, larger studies are needed to test this idea.

How fluoxetine works

Fluoxetine works by increasing the stimulation between some cells in the brain.

How fluoxetine is given

Fluoxetine is taken orally, as tablets. Dosages vary and it is normally prescribed by a GP.

Fluoxetine is a long-term treatment. Individuals should allow four to six weeks to feel the benefit of fluoxetine.

Fluoxetine remains in the body for some weeks after an individual has stopped taking the drug, therefore, individuals should not stop abruptly but taper off treatment with a doctor's advice.

Side effects

Dizziness or lightheadedness particularly on getting up from lying or sitting position, dry mouth, decreased sexual drive or ability, diarrhoea, drowsiness, headache, trouble sleeping, abnormal dreams, fast or irregular heartbeat, frequent urination, menstrual pain, tiredness or weakness, tremor, vomiting. Most of these are transitory and will go away once someone has adjusted to the medication.

Fluoxetine can interfere with sleep, so is best taken in the morning. It can upset the stomach and may be taken with or after food.

Contraindications

Fluoxetine should not be taken by people with reduced liver function, acute heart conditions, diabetes, history of bleeding disorders, or a history of some types of mental health problems. It should also not be taken during pregnancy or when still breastfeeding.

Fluoxetine can interact with other medications that affect the central nervous system, notably carbamazepine, phenytoin and diazepam, affecting the rate at which they are absorbed.

References

Shafey H.
The effect of fluoxetine in depression associated with multiple sclerosis.
Canadian Journal of Psychiatry 1992;37(2):147-148.
abstract

Mostert JP, et al.
Effects of fluoxetine on disease activity in relapsing multiple sclerosis: a double-blind, placebo-controlled, exploratory study.
Journal of Neurology Neurosurgery and Psychiatry 2008;79(9):1027-1031.
abstract

Patient Information Leaflets

Prozac (EMC website)

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