Fluoxetine
Also sold as: Prozac
Usual adult dose
Usual adult dose: 20 mg once a day in the morning. The doctor may raise the dose slowly; it can take 2 to 4 weeks to feel better. Do not stop it suddenly without your doctor.
Your doctor may give you a different dose. Children's doses depend on weight.
Side effects
Common
- nausea
- headache
- trouble sleeping
- nervousness
- loss of appetite
- sexual problems
Serious — get help
Stop taking it and see a doctor straight away if you notice:
- thoughts of suicide or self-harm
- severe agitation
- fever with stiff muscles and confusion
- seizures
- severe allergic reaction
Do not take it, or take care, if
- Taking, or recently stopped, an MAO inhibitor antidepressant
- Bipolar disorder (use with caution)
- Epilepsy (use with caution)
- Young people under 25 (watch closely for suicidal thoughts)
- Pregnancy and breastfeeding (ask your doctor)
Interactions
Medicines that can react with this one.
Serious3 medicinesDo not take these together unless your doctor says so.
- Dextromethorphan
Fluoxetine raises dextromethorphan levels and the combination can cause serotonin syndrome.
- Pethidine
Risk of serotonin syndrome.
- Tramadol
Together they raise the risk of serotonin syndrome and seizures.
Moderate10 medicinesTake together only with care. Ask your doctor or pharmacist.
- Amitriptyline
Fluoxetine raises amitriptyline levels and its side effects.
- Aripiprazole
Fluoxetine raises aripiprazole levels; the dose may need to be lowered.
- Codeine
Fluoxetine blocks the change of codeine into its active form, so pain relief may be poor.
- Imipramine
Fluoxetine raises imipramine levels and its side effects.
- Metoprolol
Fluoxetine raises metoprolol levels and can slow the heart too much.
- Ondansetron
The combination can increase the risk of serotonin syndrome.
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- Phenytoin
Fluoxetine can raise phenytoin levels and cause toxicity.
- Risperidone
Fluoxetine raises risperidone levels and its side effects.
- Sumatriptan
The combination can rarely cause serotonin syndrome.
- Warfarin
Fluoxetine can increase the bleeding risk with warfarin; INR should be checked.