Prozac vs Zoloft

What is Prozac?

Prozac is a Brand name for an antidepressant medicine that contains fluoxetine as an active ingredient. Fluoxetine belongs to the class of SSRI – selective serotonin reuptake inhibitors antidepressants.

Chemically, fluoxetine is a racemic mixture of the R- and S- enantiomers with equivalent pharmacologic activity. Fluoxetine works by affecting chemical signaling between nerve cells in the brain and/or by restoring neurotransmitter’s balance in the brain. It is most commonly prescribed for the treatment of Depression, Panic disorder and obsessive-compulsive disorder.

Prozac is available in the form of: capsules in doses of 10 mg, 20 mg and 40 mg, oral liquid in dose of 20 mg and in form of delayed release capsule in dose of 90 mg.   Food and Drug Administration (FDA) approved fluoxetine in 1987. Prozac is manufacturing by Eli Lilly and Company.

What is Prozac used for?

Prozac labeled indications include:

  • Panic disorder
  • Obsessive-compulsive Disorder
  • Depressive disorder
  • Bipolar I depression
  • Anorexia Nervosa
  • Bulimia nervosa
  • Cataplexy
  • Myoclonus
  • Alcohol dependence
  • Obesity
  • Premature ejaculation
  • Premenstrual Dysphoric Disorder, condition  before menstruation in which a woman has symptoms of depression, irritability and increased tension
  • Trichotillomania or hair pulling disorder.

In some cases, Prozac is used together with olanzapine (Zyprexa) for the treatment of depression caused by bipolar disorder (manic depression). This combination is also used to treat depression after at least 2 other medications have been tried without successful treatment of symptoms.

Prozac is commonly used off-label for next indications:

  • Autism,
  • Social anxiety disorder
  • Post-traumatic stress disorder (PTSD)
  • Chronic neuropathic pain
  • Fibromyalgia
  • Mild dementia-associated agitation in nonpsychotic patients
  • Raynaud’s phenomenon.

What is Zoloft?

Zoloft is a Brand name for an antidepressant medicine that contains sertraline as an active ingredient. Sertraline belongs to the class of SSRI – selective serotonin reuptake inhibitors antidepressants. Sertraline works by affecting chemical signaling between nerve cells in the brain and/or by restoring neurotransmitter’s balance in the brain.

It is most commonly prescribed for the treatment of Major Depressive Disorder, Panic disorder, Obsessive-compulsive disorder and Social anxiety disorders. Zoloft is available in the form of: film coated tablets in doses of 25 mg, 50 mg and 100 mg, capsules in doses of 25 mg, 50 mg and 100 mg and oral solution concentrate in dose of 20 mg/ml.

The Food and Drug Administration (FDA) approved sertraline in 1999. Zoloft is manufacturing by Pfizer, UK.  In 2013, Zoloft was the most prescribed antidepressant drug and second most prescribed psychiatric medication on the U.S. retail market.

What is Zoloft used for?

Zoloft indications are:

  • Management of major depressive disorder
  • Posttraumatic stress disorder
  • Obsessive-compulsive disorder
  • Panic disorder with or without agoraphobia
  • Premenstrual dysphoric disorder
  • Social phobia
  • Premature ejaculation
  • Vascular headaches

How Prozac and Zoloft work in the body?

Fluoxetine, the active ingredient of Prozac and Sertraline, the active ingredient of Zoloft are antidepressant drugs belonging to the class of selective serotonin reuptake inhibitors (SSRIs). SSRI’s have little to no effect on dopamine or norepinephrine reuptake and do not antagonize α- or β-adrenergic, histamine H1 or dopamine D2 receptors compared to tricyclic antidepressants.

Before its actions, fluoxetine is metabolized to norfluoxetine. During acute use, fluoxetine and sertraline block reuptake of serotonin and increase serotonin stimulation of post synaptic 5-HT1A and terminal autoreceptors. Chronic use leads to 5-HT1A and terminal autoreceptors desensitization.

The overall clinical effect of decreased anxiety and increased mood is thought to be caused due to adaptive changes in neuronal function leading to enhanced serotonergic neurotransmission.

Fluoxetine is known to binds with less affinity to acetylcholine, histamine and norepinephrine receptors compared to tricyclic antidepressant drugs.

Similarities between Prozac and Zoloft

Both drugs are classified in the group of antidepressants known as selective serotonin reuptake inhibitors (SSRIs). Prozac and Zoloft both work by influencing serotonin levels in CNS. Their mechanism of action is almost the same.

By balancing serotonin and other neurotransmitters in the brain, these drugs improve mood and appetite; enhance energy levels and help sleep better. For patients with major depression, they can dramatically improve quality of life.  Both drugs can successfully reduce anxiety, fear, and compulsive behaviors.

Both drugs are intended for oral use. Their same approved indications are: depressive disorder, panic attacks, obsessive-compulsive disorder and premenstrual dysphoric disorder. Both drugs may cause: diarrhea, nausea and vomiting, dizziness, sexual problems, such as erectile dysfunction, weight gain, weight loss, headache and dry mouth as side effects.

Prozac or Zoloft should be avoided during pregnancy or breastfeeding. In general, they should be used during pregnancy only in cases if the potential benefit outweighs the potential risk.  For both drugs it may take up to 4 weeks or longer before they start working. These medicines should not be stopped abruptly, as they may cause serious withdrawal symptoms. However, both drugs have no potential for misuse. Both should be taken once daily, and they work in 50-70 % of patients who take them.

Difference between Prozac and Zoloft

Although both drugs are classified in the same group, chemically they are not similar molecules. Fluoxetine is a derivative of phenoxy propane amine, while Sertraline derivative of naphtalen amine. Also Fluoxetine is a racemic mixture of R- and S- enantiomers and prodrug form that metabolizes in the body to norfluoxetine which is the most active metabolite.

prozac-zoloft

Main differences between Prozac and Zoloft are in their approved indications of use.  Zoloft is labeled for the treatment of PTSD – post traumatic stress disorder and social anxiety disorder or social phobia while Prozac is not, but it is often used off-label for these indications.

Prozac is indicated for the treatment of anorexia and bulimia nervosa while Prozac is not.  Some studies have found that many patients showed better responses in Zoloft’s efficacy for treating depression compared to Prozac.  But, one study also found that Prozac is certainly not better than and probably not worse than Zoloft.

Prozac is the only medicine that is FDA approved for treating depression in children who are 8 years or older. It’s also used to treat obsessive compulsive disorder in children who are 7 years or older. Additionally, it is used for adults for all of its uses. Zoloft is approved to treat adults and children who are 6 years or older for obsessive compulsive disorder. Otherwise, for its other uses, Zoloft is only approved to treat adults.

Also, important difference between these two drugs is in their side effects profiles.  Prozac causes less feeling of being slowed down and sleepiness, but it has been showed that Prozac might cause more of anxiety and irritability. Prozac also causes more dry mouth than Zoloft. On the other hand, diarrhea is more associated with Zoloft than Prozac.

Studies have also showed that Prozac has a slower onset of antidepressant action than other SSRIs drugs. Also, Prozac appears to be slightly less effective, than other drugs in this class.  Zoloft may have a slightly higher rate of response than Prozac.

Prozac half-life time is 1-3 days for acute administration, 4-6 days for chronic administration and 4-16 days for its metabolite norfluoxetine after acute and chronic administration. Sertraline’s elimination half-life is approximately 25-26 hours. The elimination half-life of its metabolite desmethylsertraline is approximately 62-104 hours.

Which one is expensive, Prozac or Zoloft?

A 30-day supply of Prozac is about $100 more expensive than a similar supply of Zoloft.  Most health insurance plans likely won’t cover brand-name Prozac or Zoloft. This is because both drugs are also available as generic medications, and generics are cheaper than their brand-name counterparts. Before covering the brand-name product, your health insurance company may need prior authorization from your doctor.

Prozac and Zoloft side effects

Prozac can cause next side effects:

Very common side effects:

  • 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%)

Common side effects:

  • 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%)

Zoloft can cause next side effects:

Very common side effects:

  • Diarrhea (13-24%)
  • Nausea (13-30%)
  • Headache (20-25%)
  • Insomnia (12-28%)
  • Ejaculation disorder (7-19%)
  • Dizziness (6-17%)
  • Dry mouth (6-16%)
  • Fatigue (10-16%) and Drowsiness (2-15%)

Common side effects:

  • Agitation (1-6%)
  • Anorexia (5-10%)
  • Anxiety (4%)
  • Constipation (5-8%)
  • Paresthesia (2%)
  • Impotence (5-10%)
  • Sweating (< 1%)
  • Malaise (7-9%)
  • Vomiting (4%)
  • Pain (3-6%)

Prozac and Zoloft withdrawal

All SSRIs drugs aren’t considered as addictive. However, discontinuing treatment abruptly or missing several doses can cause withdrawal syndrome accompanied by withdrawal symptoms, such as nausea, dizziness, headache, lethargy and flu-like symptoms. All SSRI’s do not have the same type or severity of withdrawal symptoms.

Withdrawal syndrome is more likely with SSRIs with shorter half-lives and with inactive metabolites, such as sertraline – Zoloft, fluvoxamine and paroxetine. The incidence of withdrawal syndrome is highest with paroxetine followed by sertraline and fluvoxamine. Citalopram and fluoxetine – Prozac have the lowest occurrence of withdrawal symptoms.

Discontinuation of antidepressant therapy for 5-8 days was associated with the emergence of new psychological and somatic symptoms in patients treated with paroxetine and to a lesser degree sertraline, with few symptoms seen with fluoxetine.

Warnings and precautions during Prozac and Zoloft use

  • Prozac carry a black box warning because of the increased risk of suicide when taking the medicine.
  • Prozac may increase suicidal thoughts or actions in children, teenagers, and young adults during first several months of treatment or after dose changes.
  • Patients should call their doctor immediately if they experience any unusual changes in behavior or mood while on Prozac, including:

×          Thoughts about suicide or dying, or suicide attempts

×          Feeling very agitated or restless

×          New or worsening depression or anxiety

×          Panic attacks

×          New or worse irritability

×          Difficulty sleeping

×          Being aggressive, angry, or violent

×          Extreme increase in activity and talking

×          Acting on dangerous impulses

×          Decreased need for sleep

  • Patients with a history of seizures; bipolar disorder; heart problems, including heart rhythm problems; liver disease; diabetes; glaucoma; or thoughts of suicide or attempted suicide should talk with their doctors before using these drugs.
  • Patients may not feel Prozac full benefits for 4 to 6 weeks or longer after starting the therapy
  • Stopping Prozac suddenly may cause serious withdrawal side effects. Never abrupt the therapy with Prozac suddenly
  • Don’t take Prozac or other forms of fluoxetine
  • Prozac should not be used if patients are taking a monoamine oxidase inhibitor drugs such as phenelzine or if you took an MAOI in the past 14 days. A dangerous drug interaction could occur, leading to even death.
  • Avoid operating heavy machinery, driving a motor vehicle, or performing other dangerous activities during Prozac treatment because the drug can cause sleepiness and may worsen ability to make decisions, judge or react quickly.
  • Zoloft also carries a black-box warning because of an increased risk of suicide among patients and abusers who are taking this drug.
  • It has been shown that Zoloft can increase suicidal thoughts and actions in children, adolescents, and younger adults who already have diagnosed major depressive disorder or other psychiatric problems. However, in older than 24, there is no increased risk and there is a reduction of same risk among adults 65 and older.
  • Zoloft is not approved for use in children, but it may be used if they are suffering from obsessive-compulsive disorder.
  • If patients feel irritable, agitated, hostile, restless, aggressive, impulsive, or if they notice that they are even more depressed or suicidal, they should see their doctor right away.
  • If you are taking a drug screening test, let the laboratory technician know you are using Zoloft since it could affect your test results.
  • Zoloft should not be used if patients are taking a monoamine oxidase inhibitor drugs such as phenelzine or if you took an MAOI in the past 14 days. A dangerous drug interaction could occur, leading to even death.
  • Patients with a history of seizures; bipolar disorder; heart problems, including heart rhythm problems; liver or kidney disease; diabetes; glaucoma; or thoughts of suicide or attempted suicide should talk with their doctors before using these drugs.
  • It may take up to four weeks before you feel Zoloft benefits.
  • Stopping Zoloft suddenly may cause serious withdrawal side effects. Never abrupt the therapy with Prozac suddenly

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