Introduction
Fluoxetine is a type of antidepressant belonging to the selective serotonin reuptake inhibitor (SSRI) group of medicines. It is widely prescribed to treat depression and other mental health conditions like panic disorder and obsessive-compulsive disorder.
Fluoxetine helps many people to recover from depression by improving their mood and relieving anxiety and tension. It is also used to treat bulimia nervosa (an eating disorder), where it reduces binge-eating and purging (vomiting).
The dose and how often you need it will be decided by your doctor so that you get the right amount to control your symptoms. Your doctor may start you on a lower dose and increase it gradually. Do not change the dose or stop taking it without talking to your doctor, even if you feel well. Doing so may make your condition worse or you may suffer from unpleasant withdrawal symptoms (anxiety, restlessness, palpitations, dizziness, sleep disturbances, etc).
To get the most benefit, take this medicine regularly at the same time each day. It may take a few weeks before you start feeling better. Let your doctor know if you do not see any improvement even after 4 weeks. Some common side effects of Fluoxetine include nausea, indigestion, dry mouth, fatigue, loss of appetite, increased sweating, sinusitis, insomnia (difficulty in sleeping), yawning, and abnormal dreams. Sexual side effects like decreased sexual drive delayed ejaculation, and erectile dysfunction may also be seen. Let your doctor know straight away if you develop any sudden worsening of mood or any thoughts about harming yourself.
Before taking this medicine, you should tell your doctor if you have epilepsy (seizure disorder or fits), diabetes, liver or kidney disease, heart problems, or glaucoma. These may affect your treatment. Pregnant or breastfeeding women should also consult their doctor before taking it. Some other medicines may affect the way it works, especially other antidepressants and medicines called MAO inhibitors. Please tell your doctor about all the medicines you are taking to make sure you are safe.
Uses of Fluoxetine
- Depression
- Panic disorder
- Obsessive-compulsive disorder
- Bulimia nervosa
Side effects of Fluoxetine
Common
- Erectile dysfunction
- Indigestion
- Influenza like syndrome
- Loss of appetite
- Low sexual desire
- Nausea
- Sore throat
- Sweating
- Tremor
- Weakness
- Yawning
- Abnormal dreams
- Delayed ejaculation
- Dryness in mouth
- Insomnia (difficulty in sleeping)
- Nervousness
- Sleepiness
- Sinus infection
How to use Fluoxetine
Take this medicine in the dose and duration as advised by your doctor. Do not chew, crush or break it. Fluoxetine may be taken with or without food, but it is better to take it at a fixed time.
How Fluoxetine works
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant. It works by increasing the levels of serotonin, a chemical messenger in the brain. This improves mood and physical symptoms of depression and also relieves symptoms of panic and obsessive disorders.
Indication
Panic disorder, Obsessive compulsive disorder, Trichotillomania, Premenstrual dysphoric disorder, Major depression, Post-traumatic stress disorder, Bulimia nervosa, Body dysmorphic disorder, Binge eating disorder
Administration
May be taken with or without food.
Adult Dose
Oral
Depression
Adult: Initially, 20 mg once daily. May gradually increase up to max 80 mg daily in 2 divided doses, if no clinical response after several wk.
Bulimia nervosa
Adult: 60 mg daily as a single or in divided doses.
Hepatic impairment: Reduce dose and/or dosing frequency.
Obsessive compulsive disorder
Adult: Initially, 20 mg once daily, increased up to 60 mg daily if no clinical response after several wk. Max: 80 mg daily in 2 divided doses.
Premenstrual dysphoric disorder
Adult: 20 mg daily continuously. Alternatively, 20 mg daily to be started 14 days before menstruation and continued until 1st day of menses; repeat w/ each cycle.
Panic disorder
Adult: Initially, 10 mg once daily, increase to 20 mg daily after a wk. May further increase to 60 mg daily, if no clinical response after several wk.
Elderly: Max: 60 mg daily.
Hepatic impairment: Reduce dose and/or dosing frequency.
Child Dose
Oral
Depression
Child: >8 yr Initially, 10 mg daily, may increase to 20 mg daily after 1-2 wk.
Low wt childn: Initially, 10 mg daily, may increase to 20 mg daily after several wk, only if clinical response is insufficient.
Obsessive compulsive disorder
Child: >7 yr Initially, 10 mg daily, may increase to 20 mg daily after 2 wk; increase further up to 60 mg daily after several wk as necessary.
Low-wt childn: Initially, 10 mg daily, may increase to 20-30 mg daily after several wk, if required.
Renal Dose
Renal impairment: Use caution; drug accumulation may occur with severe renal impairment
Contraindication
Severe renal or hepatic failure; hypersensitivity; lactation; concomitant MAOIs or within 2 wk of MAOI withdrawal.
Mode of Action
Fluoxetine is a potent and highly selective inhibitor of serotonin (5-HT) re-uptake. No affinity for adrenoceptors or histamine, GABA-B, or muscarinic receptors.
Precaution
Unstable epilepsy, liver and renal impairment, cardiac disease, diabetes, electroconvulsive therapy, bleeding disorders, closed-angle glaucoma; pregnancy. May impair performace of skilled tasks; withdraw gradually. Close monitoring of clinical worsening and behavioural changes during the 1st few mth of treatment or when there are dose changes.
Lactation
Excreted in milk; avoid (AAP states effect on nursing infants is unknown but may be of concern)
Side Effect
>10%
Headache (20-25%),Nausea (12-29%),Insomnia (10-33%),Anorexia (4-17%),Anxiety (6-15%),Asthenia (10-15%),Diarrhea (8-18%),Nervousness (8-14%),Somnolence (5-17%),Tremor (3-13%),Weakness (7-21%)
1-10%
Dizziness (9%),Dry mouth (6-10%),Dyspepsia (6-10%),Sweating (5-10%),Decreased libido (2-5%),Abnormal taste (>1%),Agitation (>1%),Chest pain (>1%),Chills (>1%),Confusion (>1%),Ear pain (>1%),Hypertension (>1%),Increased appetite (>1%),Palpitation (>1%),Sleep disorder (>1%),Tinnitus (>1%),Urinary frequency (>1%),Vomiting (>1%),Weight gain (>1%)
Frequency Not Defined
Dysglycemia in patients with DM
Risk of seizure with concomitant electroconvulsive therapy (rare)
Potentially Fatal: Rarely, systemic events possibly related to vasculitis have been reported in patients with rash but may be serious involving lungs, kidney and liver.
Pregnancy Category Note
Pregnancy category: C
Treatment of pregnant women during the first trimester: There are no adequate and well-controlled clinical studies on the use of fluoxetine in pregnant women, but 1 prospective cohort study conducted by the European Network of Teratology Information Services reported an increased risk of cardiovascular malformations in infants born to women (N = 253) exposed to fluoxetine during the first trimester of pregnancy, compared with infants of women (N = 1359) who were not exposed to fluoxetine
Use late in the third trimester associated with complications in newborns and may require prolonged hospitalization, respiratory support, and tube feeding
When treating a pregnant woman with fluoxetine, physician should carefully consider trimester both for the potential risks of taking an SSRI, along with the established benefits of treating depression with an antidepressant; the decision can only be made on a case by case basis
Lactation
Excreted in milk; avoid (AAP states effect on nursing infants is unknown but may be of concern)
Interaction
May cause transient shift in plasma conc of tightly protein bound drugs e.g. warfarin and digoxin, resulting in adverse effects. T1/2 of diazepam is prolonged. Avoid concurrent use with clopidogrel.
Potentially Fatal: Serious reactions when combined with MAOIs; at least 14 days should elapse after MAOIs withdrawal before starting fluoxetine treatment or at least 5 wk should elapse after fluoxetine treatment before starting MAOIs therapy. Two-fold increase in plasma levels of other antidepressants when combined with fluoxetine. Monitor lithium levels when combined.