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How Does Prozac Work In The Brain

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How Antidepressants Work In The Brain: A Comprehensive Guide

How does fluoxetine (Prozac) work?

Antidepressants are currently prescribed more than at any other point in the past two decades. One in 10 Americans takes them. Among women in their 40s and 50s, that number rises to one in four, according to the latest numbers in the National Health and Nutrition Examination Survey. Yet, despite millions of people taking the drugs, scientists still arent exactly sure what causes depression. Through years of research, theyve come to understand that it likely culminates from a variety of factors. Feel-good neurotransmitters, such as serotonin and dopamine, certainly play a part as they affect mood. But a host of other factors may also contribute, such as genetic predisposition, stressful life events, and other medical problems.

With little insight into how these other factors play a part, as well as an incomplete understanding of the brain networks that underpin our moods, scientists have only been able to develop antidepressant drugs that work to control how neurotransmitters affect the brain. Because of the aforementioned reasons, sometimes they work and sometimes they dont. Either way, its important to understand how they affect the brain.

Precautions When Taking Prozac

Prozac may not be safe for you if you have certain health or medical conditions. Ask your doctor for more information about the risks and benefits of Prozac for you.

  • Liver disease. If you have problems with your liver, your doctor may need to adjust your dose of Prozac or consider other medications to manage your anxiety.
  • Seizures. If you have a history of seizure disorder, your doctor will discuss your risks if you choose to take Prozac.
  • Bipolar 1 disorder. Prozac can increase the risk of manic episodes when used alone in people with bipolar disorder.
  • Blood clotting disorders. If youre taking medications like warfarin to thin your blood, Prozac can increase your risk of bleeding.
  • Pregnant or breastfeeding. It isnt known if Prozac is safe during pregnancy or while breastfeeding. Ask your doctor about the benefits and risks of Prozac if youre pregnant or breastfeeding.

Fearless Youth: Prozac Extinguishes Anxiety By Rejuvenating The Brain

New research shows that the antidepressant reduces fear in adult mice by increasing brain plasticity

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Once adult lab mice learn to associate a particular stimulusa sound, a flash of lightwith the pain of an electric shock, they don’t easily forget it, even when researchers stop the shocks. But a new study in the December 23 issue of Science shows that the antidepressant Prozac gives mice the youthful brain plasticity they need to learn that a once-threatening stimulus is now benign. The research may help explain why a combination of therapy and antidepressants is more effective at treating depression, anxiety and post-traumatic stress disorder than either drugs or therapy alone. Antidepressants may prime the adult brain to rewire faulty circuits during therapy.

Nina Karpova, Eero Castrén and their colleagues at the University of Helsinki’s Neuroscience Center created and extinguished fearful behaviors in mice. First, Castrén placed mice in a cage and repeatedly played a tone just before electrically shocking their feet. Soon the animals froze in fear whenever they heard the tone, at which point Castrén put them through “extinction training.” He moved the mice to a different cage and played the same tone again. This time there was no electric shock.

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Is Prozac A Controlled Substance

Controlled substances are defined as drugs that have a high potential for abuse and addiction, according to the Controlled Substances Act of 1970. Drugs that fit the definition of controlled substances are listed on controlled substance schedules according to the level of risk of abuse and addiction, as determined by the United States Department of Justices Drug Enforcement Agency . The DEA does not consider fluoxetine to have a high risk of abuse or addiction, so it is not listed on the controlled substances schedules.

How A Popular Antidepressant Drug Could Rewire The Brain

SSRIs (Selective Serotonin Reuptake Inhibitors)
American Chemical Society
Prozac®, the trade name for the drug fluoxetine, was introduced to the US market for the treatment of depression in 1988. Thirty years later, scientists still don’t know exactly how the medication exerts its mood-lifting effects. Now, researchers report that, in addition to the drug’s known action on serotonin receptors, fluoxetine could rearrange nerve fibers in the hippocampus of mouse brains.

Prozac®, the trade name for the drug fluoxetine, was introduced to the U.S. market for the treatment of depression in 1988. Thirty years later, scientists still don’t know exactly how the medication exerts its mood-lifting effects. Now, researchers report that, in addition to the drug’s known action on serotonin receptors, fluoxetine could rearrange nerve fibers in the hippocampus of mouse brains. They report their results in ACS Chemical Neuroscience.

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How Common Is Prozac

Prozac and its generic equivalent, fluoxetine, are commonly prescribed by physicians. In 2017, 21,913,276 prescriptions for fluoxetine were written in the United States, making it the 31st most commonly prescribed drug in the country for that year. Prescriptions for fluoxetine peaked in 2015 when it was the 20th most prescribed drug.3

See Effects Of Antidepressants Span Three Generations In Fish

The team sought to gain insight into why that might be. To study the effects of this drug on youngsters in particular, the researchers set up an experiment where they took a group of one-year-old macaquesapproximately equivalent in development to a 4 to 6-year-old humanand gave roughly half of them fluoxetine for 2 years . The other half received a placebo. Along the way, they looked at the drugs effect on the monkeys levels of impulsivity, sleep, and social interaction, as well as measured the levels of potential biomarkers of treatment response in their blood.

As a further step, the team was interested in getting a more holistic, long-term view of what was going on in the monkeys brainsincluding looking at lipids, since previous work with rodents and reports from human patients had hinted that there may be changes to those biomoleculesbut they lacked the capacity to do this themselves. So, they reached out to the lab of researcher Philipp Khaitovich in Moscow, who put Tkachev and her team on the problem.

Tkachevs group took post-mortem brain tissue from the monkeys, who had been taken off of fluoxetine for a year following their 2-year regimen, and looked for a variety of possible differences between the treatment and control groups. This included looking for divergences in polar metabolites or gene expression levels, as well as any differences in the tissues lipids.

As my supervisor would end his talks, says Tkachev: Lipids are cool.

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How Does Fluoxetine Work

Fluoxetine works by enhancing the activity of a neurotransmitter called serotonin in the brain.

Neurotransmitters are natural body chemicals that act as chemical messengers between the nerve cells. Serotonin is a neurotransmitter known to be involved in regulating emotions, mood and behaviour, among other things. In depression and anxiety disorders there is a decreased amount of serotonin released from nerve cells in the brain.

Fluoxetine works by stopping the serotonin that has been released from being reabsorbed back into the nerve cells in the brain. This helps to prolong its effects and over time this helps to lighten mood and relieve depression. Antidepressants like fluoxetine have also been found to be effective in relieving symptoms of anxiety, such as panic and fear.

Read more about fluoxetine

How Long Does Fluoxetine Stay In Your System

2-Minute Neuroscience: Selective Serotonin Reuptake Inhibitors (SSRIs)

Compared to other antidepressants, fluoxetine has a very long half-life. Its also unique in that its metabolism is inhibited by its metabolite, norfluoxetine, meaning it typically takes longer for fluoxetine to exit your system the longer you have been using the medication.

In most people, it takes between one and three days for one dose of fluoxetine to reach half of its original concentration in the body.

If fluoxetine has been used for the long term, it may take four to six days for the medication to reach half of its original concentration in the body. Following long-term use, it takes around 25 days of non-use for 99 percent of fluoxetine to exit your body.

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How Do Antidepressants Work

They Balance Brain Chemicals

Brain chemicals called neurotransmitters affect mood. People who suffer from depression and other mood disorders may have altered levels of these chemicals. Antidepressants work by helping to normalize the levels of these compounds. This makes the brain chemicals more available to do their job in the brain. All physicians have the ability to prescribe antidepressants. People who have severe or difficult-to-treat mood imbalances are best treated by a doctor who is an expert in sing medications to help balance brain chemistry. These doctors are called psychiatrists. Depression and mental health disorders are serious issues that need to be treated by a medical professional.

Types of Antidepressants

What Antidepressants Can Do To A Brain That Is Not Depressed

There’s a word of warning after research on monkeys finds that an SSRI antidepressant may alter brain architecture if taken by those who aren’t really depressed.

There is new reason to be cautious about using popular antidepressants in people who are not really depressed.

For the first time, research has shown that a widely used antidepressant may cause subtle changes in brain structure and function when taken by those who are not depressed. The drug is sertraline. It is most commonly known as Zoloft and is present in 16 other generic forms in Australia.

There has been long debate about the effect such drugs can have on the architecture of the brain. While the changes it induces in the depressed brain are regarded as advantageous, researchers wanted to know what happens in the brains of those who are not depressed. They wanted to know because these drugs are commonly used for other conditions such as anxiety, bulimia, hot flushes, obsessive-compulsive disorder, post-traumatic stress disorder, stroke recovery and sexual dysfunction

Their study revealed the drugs can have unexpected and unwanted effects.

The drug used in this trial is a SSRI, a selective serotonin reuptake inhibitor, and experts say other drugs in this class work on the same mechanism and chemistry and would likely have the same effect.

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History And Importance In Neuroscience

The earliest classesof antidepressant medications, which dominatedthe clinical landscape from the 1950s through the 1970s, were discoveredserendipitously. Tricyclic antidepressants were developed in the 1950s in the wake of the discovery thatchlorpromazine 16, derived from early synthetic antihistamines,acted as an antipsychotic agent .,, This breakthrough led to thesynthesis and pharmacological evaluation of other analogues of 16, such as imipramine 17, the first TCA to bedeveloped. Numerous efforts followed the development of 17, includingthe introduction of amitriptyline 18 by Merck in 1961. For many years, TCAs were the standard of care for depression., It was later discovered that TCAs exert their antidepressant affectsby blocking both the serotonin transporter and the norepinephrinetransporter , increasing extracellular concentrations of serotonin 19 and norepinephrine 20, with little effecton dopamine 21., However, TCAs have promiscuous pharmacology, with agonist or antagonistactivity at multiple muscarinic, adrenergic, histamine, serotonin,and NMDA receptor subtypes, which engender significant adverse effects.,, Moreover, TCAs are potent inhibitors ofL-type calcium and sodium channels, leading to potentially lethalhypertension and arrhythmias. Thus, TCAoverdose is often fatal, which limits the use of these compounds ina patient population which is at risk for suicidal behavior.

Finding The Brain Cells That Make Popular Antidepressants Work


    Drugs like Prozac are known to relieve depression by increasing the amount of serotonin in the brain.

    But beyond that, the details of how the SSRIs work are fuzzy. Serotonin activates 14 different types of receptors in the brain that are spread throughout hundreds of different types of cells. Which of these cells and receptors are responsible for triggering the relief of symptoms?

    A new study in mice by René Hen, PhD, now shows that fluoxetine must act on cells in the brains dentate gyrus in order to work.

    The dentate gyrus is an extraordinary part of the brain, one of only two locations in the mammalian brain where new neurons are created after birth. About 10 years ago, Dr. Hen discovered that those new adult-born neurons were responsible for alleviating some symptoms of depression in mice, but not others. .

    The new research shows that the DGs mature cells enable all of fluoxetines antidepressant effects in mice, via the cells 1A serotonin receptors. When the researchers created a strain of mice with mature DG cells lacking 1A serotonin receptors, fluoxetine had no effect on the animals depression-like behaviors.

    The mature cells are also responsible for boosting the birth rate of new DG neurons. We need both the young and the mature cells for a complete response, Dr. Hen says.

    The findings should help researchers discover new ways to treat depression, especially in people who do not respond to fluoxetine and other SSRIs.

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    Interactions Between Fluoxetine And Other Medications

    Fluoxetine can interact with other medications, including common prescription drugs and some over-the-counter medications, supplements and herbal products. These interactions can make fluoxetine more or less effective and, in some cases, cause serious health issues.

    You should not use fluoxetine if you have used any monoamine oxidase inhibitors in the last 14 days. MAOIs are a type of medication prescribed to treat depression. Widely-used MAOIs include phenelzine, isocarboxazid, tranylcypromine, selegiline and others.

    These medications can interact and cause serious, life-threatening side effects including rapid changes in blood pressure and heart rate, muscle spasms, high fever and loss of consciousness.

    You should also not use fluoxetine with the antipsychotic medications thioridazine or pimozide. These medications can cause severe and potentially deadly heart rhythm problems when used with fluoxetine.

    Fluoxetine may also interact with other medications, causing an increased risk of experiencing certain side effects. You should not use fluoxetine with:

    • Other antidepressants, including SSRIs, SNRIs and tricyclic antidepressants

    • Opioid painkillers, such as tramadol and fentanyl

    • Nonsteroidal anti-inflammatory drugs

    • St. Johns wort

    • Warfarin

    To avoid any potentially hazardous drug interactions, inform your healthcare provider of all prescription and over-the-counter medications that you either currently use or have recently used before talking about fluoxetine.

    Is Brand Name Better

    Generic Is the Same, Usually

    The US Food and Drug Administration says that the safety, strength, and quality of generic drugs are equal to those of brand-name drugs. However, in practical experience, some people notice that they do not experience the same benefits from a generic drug compared to the brand-name version. Results of some studies suggest generic medications may be absorbed and used by the body slightly differently than brand-name drugs. If you notice a generic medicine is not working as well as a brand-name medicine did for you, tell your physician.

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    Interactions Between Prozac And Other Medications

    Prozac may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements that you are currently taking. The list below does not include all possible drug interactions with Prozac . Please note that only the generic name of each medication is listed below.

    Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

    • Bepridil

    Treatment For Prozac Dependence

    How do antidepressants work? – Neil R. Jeyasingam

    The types of treatment used to end dependence on fluoxetine depend on the circumstances surrounding how the medication is used. For people who abuse Prozac or take it in an attempt to self-medicate, treatment should focus on any other substances that are abused along with fluoxetine and on the conditions that people are attempting to treat. For example, a person taking fluoxetine as an appetite suppressant should receive treatment for the eating disorder associated with this use of the medication. People who use fluoxetine and alcohol or fluoxetine and opioids together should receive treatment for abuse of those respective substances.

    As stated previously, people who want to end the use of medically prescribed fluoxetine should do so under the supervision of their physicians. Stopping Prozac cold turkey is not recommended due to the withdrawal symptoms listed above. Prozac should be tapered gradually until a person can function without the drug with no withdrawal symptoms. The longer a person has taken Prozac, the longer it will take to taper off the medication. In some cases, this may take months or even over a year.

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    Ongoing Support While Quitting Prozac

    It is important to remember that as Prozac is tapered, the symptoms that the medication was used to treat may return. A person who used fluoxetine for major depressive disorder may experience symptoms of depression again. People with obsessive-compulsive disorder may experience more intrusive thoughts. These symptoms should be monitored and managed if they occur. In some cases, a person may need to discuss the pros and cons of ending fluoxetine use with their physician, as ending the use of the drug may be worse than staying on it.

    People who want to end Prozac use should also continue with other treatments that they have received for their respective conditions. Therapy, counseling, educational services, and social support should all be in place before a person begins to end Prozac use, just in case the symptoms of the condition reappear. These services will help the person manage those symptoms as they taper the drug. If a person has not required services for a while due to the condition being stable, they should make sure to re-establish contact with service providers before tapering Prozac. Periodic monitoring by a therapist or counselor may help the patient and physician to manage symptoms and to determine how stable the patients condition is overall as the drug is tapered.

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