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Fluoxetine is most commonly used to treat symptoms of depression and anxiety. It may also be used to treat symptoms of certain eating disorders (e.g. bulimia) post-traumatic stress disorder panic attacks obsessive-compulsive disorder and premenstrual dysphoric disorder. As well it may sometimes be used to treat different chronic pain conditions (e.g. migraines nerve pain) usually when other medications are not working.

When you are feeling symptoms of depression or anxiety the chemicals in your brain are not working as well as they should or you may not have the correct amount of a certain chemical to keep things in balance. One of these chemicals is called serotonin also known as one of the "feel good" chemicals that lighten our mood and make us feel less anxious.

Fluoxetine is in a class of drugs called selective serotonin reuptake inhibitors. It works by increasing the amount of serotonin in the brain to help decrease the feelings of depression or anxiety.

You should not take this drug if you are allergic to fluoxetine or other similar drugs like citalopram paroxetine sertraline fluvoxamine. Tell your doctor if you have or have ever had (or anyone in your family has or has ever had):

• a problem with alcohol or drug abuse
• feelings of worsening depression or suicidal
• a condition called bipolar disorder
• seizures
• problems with your liver
• problems with sex drive ability or orgasm
• heart disease or heart rhythm problems
• problems with a decreased amount of salt (sodium) in your blood
• diabetes

The most common side effects include:

• nausea and loss of appetite
• diarrhea
• difficulty falling and staying asleep
• feeling excited agitated or nervous
• headache
• decrease in sex drive; delayed or no orgasm
• dry mouth
• feeling extremely tired
• dizziness
• shaking hands that you cannot control
• excessive sweating
• rash

These side effects are usually related to dose the use of other medications and other factors (e.g. older age other medical conditions). As well some of these symptoms tend to go away within a few weeks of starting treatment and in most cases aren't serious enough to cause people to stop taking fluoxetine. Talk to your doctor or pharmacist about whether you have any risk factors that may make you more sensitive to these side effects. Contact your doctor if these symptoms continue or become worse.

Less common and possibly severe side effects include:

• very rare cases of hepatitis (inflammation of the liver) and jaundice (yellowing of skin and eyes) have been reported - call your doctor immediately
• seizures - call your doctor immediately
• abnormal bleeding or bruising - call your doctor immediately
• low sodium in the blood (older people on water pills are at greater risk)
• low blood sugar (rare but people with diabetes may be at greater risk)
• producing milk (lactating) in women that is not due to recent childbirth
• changes in vision
• changes in heart rhythm

This is not a complete list of side effects. If you are concerned about these or other unusual symptoms while taking this medication ask your doctor and/or pharmacist for more information and advice.

Health Canada has issued a special advisory that says people of all ages who take newer antidepressant drugs may experience behavioural and emotional changes that may increase the risk of suicide. (See other information section).

Read: Health Canada advises Canadians of stronger warnings for SSRIs and other newer anti-depressants

Always provide your doctor with a list of all other drugs you are taking (including over-the-counter medications and herbal/natural products) as they may interact and may change the safety or effectiveness of either drug. Tell your doctor specifically if you are taking any of these drugs as these are the most common interactions and he/she may need to make changes or monitor you more closely.

• phenelzine tranylcypromine moclobemide thioridizine - avoid the use of these drugs together. Must wait 2-5 weeks after stopping one before you can start the other. Talk to your pharmacist or doctor.
• Amphetamine-like drugs methylphenidate L-tryptophan selegeline sibutramine sumatriptan dextromethorphan St. johns wort amitriptyline imiprimine desipramine nortriptyline buspirone (may increase your chances of having side effects such as high blood pressure rapid heart beat sweating shaking hands fever feeling excited confusion)
• other antidepressants (increase chances for similar side effects)
• warfarin ASA & other anti-inflammatories (e.g. ibuprofen voltaren diclofenac) (e.g ibuprofen naproxen voltaren) - (may have increased chances of bleeding)
• digoxin (increase blood levels of digoxin and increase chance of side effects)
• lithium (increase blood levels of lithium and increase chance of side effects)
• alprazolam diazepam verapamil carbamazepine clarithromycin risperidone haloperidol amitriptyline imipramine desipramine (see changes in blood levels for fluoxetine or any of these drugs listed and increase chances for side effects)
• Simvastatin lovastatin atorvastatin (may increase chances of having muscle side effects of these medications)
• metoprolol
• Furosemide (may have an increased chance of low sodium in the blood)

This is not a complete list of drug interactions. Ask your doctor or pharmacist to review your list of medications.

If you are taking this medication for depression or anxiety:

It takes several weeks (4-6 weeks) before this medication will even start to work. Do not stop this medication if you don't feel it is working. Your doctor will follow you and adjust the dose over time to find the right dose. Sometimes people feel worse in the beginning and want to stop their medication. This is usually due to side effects which tend to go away with time. However if you feel any of the following symptoms contact your doctor right away:

• new or worsening feelings of depression
• thoughts of suicide
• extreme worry
• agitation or panic attacks
• aggressive behavior
• acting without thinking
• severe restlessness
• frenzied abnormal excitement
• any other sudden or unusual changes in behavior

Children: Fluoxetine is sometimes prescribed to treat depression and obsessive-compulsive disorder in children and adolescents between the ages of 6-17 years. Talk to your doctor.

Seniors: Should avoid taking fluoxetine. This drug lasts a long time in the body and thus increases the chances for side effects. There are shorter-acting drugs (paroxetine sertraline citalopram) that are available.

Pregnant women: Safety not fully established. Fluoxetine and other similar drugs have been used in pregnant women. Not treating the depression is often worse than the possible effects of the medication. Talk to your doctor

Women who are nursing: Must weigh the risk versus benefit. Not generally recommended. Talk to your doctor.

People who drive or operate machinery: Should not do so until they know the impact this drug has on them personally. This drug can cause drowsiness dizziness visual problems.

Alcohol: Generally not recommended as this medication may increase the sedative effects of alcohol.

Overdose: If you experience unusual drowsiness or any other unusual reactions or if you seriously exceed the recommended dosage call your doctor or 911.

Stopping the drug. Do not stop taking this drug until you have discussed it with your doctor. Stopping abruptly may cause withdrawal symptoms that feel like flu symptoms (flu-like insomnia nausea off-balance tingling sensations feeling anxious/nervous/agitated).

If you miss a dose: Take the next dose when you remember. If it is within eight hours of your next scheduled dose take it now but skip the next dose. Never double dose.

Storage conditions: Closed container; cool dry location away from excess moisture (not in the bathroom); always out of reach of children

Dietary precautions: None.