Prozac Dosage (A brief Guide)

In this blog post, we will talk about Prozac Dosage, we will also discuss what Prozac is, side effects, how to take it, who can take it, allergic symptoms, what happens if someone overdoses and some recommendations.

Prozac Dosage

According to the National Institute for Health and Care Excellence (NICE), the dosages are recommended as follows. 

Major depression

How: by mouth

Prozac Dosage for Adults:

The initial dose is 20 mg a day. The dose is increased after being assessed 3 to 4 weeks later and intervals thereafter.

The daily dose may be administered as a single or divided dose.

The maximum recommended is 60 mg per day.

Prozac Dosage for the Elderly:

Same as in a regular adult dosage, Initially 20 mg daily. The dose is increased after being assessed 3 to 4 weeks later and intervals thereafter.

The daily dose may be administered as a single or divided dose. The maximum recommended dose is 40 mg a day but doses up to 60 mg daily can be used.

Bulimia nervosa

How: by mouth

Dosage for Adults

Recommended: 60 mg a daily and it may be administered as a single or divided dose.

For Elderly

Recommended: Up to 40 mg daily and the daily dose may be administered as a single or divided dose.

Usually, the maximum dose a day is 40 mg but doses up to 60 mg daily can be used.

Obsessive-compulsive disorder

How: by mouth

Dosage for Adults

Recommended: 60 mg a daily and it may be administered as a single or divided dose.

Recommended: 20 mg a day, increased if necessary up to 60 mg a day.  The daily dose may be administered as a single or divided dose.

The dose can get increased gradually and if the treatment seems to be inadequate after 10 weeks then the dose gets increased to 60 mg a day.

Attention: these are just referenced dosages from NICE. Don’t stop your medication or change the intake unless your doctor instructs you to. 

Pregnant Women

If you are pregnant your doctor should carefully consider the potential risks for the fetus.

Neonates exposed to SSRIs or SNRIs late in the third trimester have said to develop complications requiring hospitalization, respiratory aid, and tube feeding.

Dosage forms and strengths

Prozac comes in the following dosage forms and strengths (

  • 10 mg: is an opaque green cap and opaque green body, imprinted with DISTA 3104 on the cap and Prozac 10 mg on the body
  • 20 mg: is an opaque green cap and opaque yellow body, imprinted with DISTA 3105 on the cap and Prozac 20 mg on the body
  • 40 mg: is an opaque green cap and opaque orange body, imprinted with DISTA 3107 on the cap and Prozac 40 mg on the body
  • 90 mg: Prozac Weekly Capsule is an opaque green cap and clear body containing discretely visible white pellets through the clear body of the capsule, imprinted with Lilly on the cap and 3004 and 90 mg on the body

What is Prozac?

Prozac belongs to the Selective Serotonin Reuptake Inhibitors (SSRIs) group of antidepressants and it is considered very effective when treating depression and has fewer unwanted side effects compared to older antidepressants.

Prozac is the brand name for the chemical component Fluoxetine, is also used when treating other disorders such as bulimia, obsessive-compulsive disorder (OCD), panic disorder and premenstrual dysphoric disorder (PMDD).

It is only available on prescription and it comes as tablets and capsules. 

Antidepressants are drugs prescribed to treat mental disorders. Some of the most common are:

  • Anxiety disorders
  • Phobias
  • Bulimia
  • Some medical conditions

How do Antidepressants work?

Antidepressants act in your body by prolonging or boosting the activity of neurochemicals such as noradrenaline and serotonin, which are thought to be involved in mood regulation. 

There are several different types of antidepressants, and they are:

  • selective serotonin reuptake inhibitors (SSRIs)
  • serotonin and noradrenaline reuptake inhibitors (SNRIs)
  • tricyclics and tricyclic-related drugs
  • monoamine oxidase inhibitors (MAOIs) 
  • other antidepressants

How should I take Prozac?

You can take it with or without food. Oral tablets are available at 10 mg, 20 mg or 40 mg.

It is available  in capsules, tablets, capsules with delayed-release and oral solution

Also, it can take 4-6 days for you to start seeing some improvement long term and 1-3 days short term.

The NHS says it usually takes 4 to 6 weeks for Prozac to work.

Remember, You should always follow your doctor’s instructions at all times.  

Who can take Prozac?

The NHS indicates that it can be taken by adults for depression, obsessive-compulsive disorder, and bulimia. 

According to, Prozac is indicated for the treatment of: 

  • Acute and maintenance treatment of Major Depressive Disorders.
  • Acute and maintenance treatment of obsessions and compulsions in patients with obsessive-compulsive disorder (OCD)
  • Acute and maintenance of binge-eating and vomiting behaviors in patients with moderate to severe Bulimia Nervosa.
  • Acute treatment of Panic Disorder, with or without agoraphobia. 

Prozac and Olanzapine

A combination of Prozac and Olanzapine is indicated for the treatment of: 

  • Acute treatment of depressive episodes associated with Bipolar Type I disorder.
  • Treatment-resistant depression (Major Depressive Disorder in patients, who do not respond to 2 separate trials of different antidepressants of adequate dose and duration in the current episode).


  • Talk to your doctor about any allergic reactions to fluoxetine or any other medicine in the past before you start taking Prozac.
  • If you have a heart problem, fluoxetine can speed up or change your heartbeat.
  • If you have ever taken any other antidepressant recently (even stopped for a few weeks now) tell your doctor since some antidepressants can interact with Prozac and cause very high blood pressure. 
  • If you are trying to become pregnant, you are pregnant, you suspect or you are breastfeeding, tell your doctor. 
  • If you have epilepsy or you are having electroconvulsive therapy, Prozac can increase the risk of having a seizure.
  • If you have glaucoma, Prozac can increase the pressure in your eye. 
  • If you have diabetes, Prozac can make it more difficult to keep your blood sugar stable. Start monitoring your sugar more often if you are going to start using Prozac. 

What happens if I forget a dose?

If you forget to take your Prozac don’t panic, take your dose the next day at the usual time.

Never double dose to make up for a forgotten dose.  

Allergic reaction to Prozac dosage

It is reported to be rare but it is possible to have a serious allergic reaction called anaphylaxis.

Call 999 or go to emergency services for immediate treatment.

Symptoms of an allergic reaction include:

  • Skin rash or itchy, red, swollen, blistered or peeling skin
  • Whistling sound when you breathe
  • Tightness in your chest or throat
  • Have troubles when breathing or talking
  • Your mouth, face, lips, tongue or throat start swelling. 

Prozac Side effects

Some of the most common and known side effects of fluoxetine are according to RxList are:

  • Nausea,
  • Upset stomach,
  • Constipation,
  • Headaches,
  • Anxiety,
  • Sleep problems (insomnia),
  • Drowsiness,
  • Dizziness,
  • Nervousness,
  • Heart palpitations,
  • Loss of appetite or increase in appetite,
  • Weight changes
  • Cold symptoms (stuffy nose, sneezing, sore throat),
  • Dry mouth,
  • Decreased sex drive,
  • Impotence
  • Difficulty having an orgasm

The NHS indicates that, if you and your doctor decide to stop the treatment then, your doctor will probably recommend reducing your dose gradually to help prevent additional side effects. 

Serious side effects

This is rare but it can happen, the incidence is less than 1 in 100 people, but some people may have serious side effects while taking Prozac. 

According to the NHS, you should go immediately to A&E if you experience the following symptoms:

  • Chest pain or pressure, or shortness of breath
  • Severe dizziness or passing out
  • Painful erections that last longer than 4 hours – this may happen even when you are not having sex
  • Any bleeding that is very bad or that you cannot stop, such as cuts or nosebleeds that won’t stop within 10 minutes

Prozac Drug interactions

Prozac may interact with medicines meant for cold or allergies, sedatives, narcotics, pain killers, sleeping pills, muscle relaxers, medicine for seizures or anti-anxiety medication, monoamine oxidase inhibitors (MAOIs), nonsteroidal anti-inflammatory drugs (NSAIDs), other antidepressants or medicine for migraine. 

Other drugs 

  • Alprazolam
  • Clopidogrel
  • Clozapine
  • Flecainide
  • Haloperidol
  • Nebivolol
  • Vinblastine
  • Seizure medications

Prozac Overdose

If you think you or someone else has taken a fluoxetine overdose you or someone else should get in contact with medical emergency services. 

Some of the most common symptoms of a Fluoxetine overdose are:

  • Feeling confused
  • Being unresponsive
  • Shaking uncontrollably
  • Feeling dizzy
  • Irregular or very fast heartbeat
  • Hallucinations
  • Restlessness
  • Having fever
  • Fainting
  • Losing consciousness

Possible complications after an overdose

A Prozac overdose can come with medical complications such as seizures, abnormal heart rhythm, kidney failure and respiratory. 

Symptoms of an overdose include:

  • Vomiting
  • Shaking or trembling
  • Feeling sleepy or lethargic
  • Feeling restless or agitated
  • Heart problems
  • Lung problems 
  • Seizures

Benefits of Prozac Dosage

According to some of the benefits of Prozac are described as follows:

  • Prozac may be used in the treatment of depression and it can help maintain the relief of depression in adults and children (8 -18 years).
  • Prozac may be helpful for the relief of the obsessive-compulsive symptoms in adults and children (7-17 yeats).  
  • Prozac may be helpful in the treatment of eating disorders like bulimia nervosa, relieve the symptoms (moderate to severe) such as binge-eating and vomiting.
  • Prozac may be helpful in the treatment of panic disorders in adults (with/without agoraphobia).
  • Prozac may be helpful in treating premenstrual dysphoric disorder or PMDD. 
  • Prozac is less likely to cause weight gain in comparison to other antidepressants, but it can cause insomnia.

Negative aspects of Prozac Dosage

According to some of the negative aspects of Fluoxetine are described as follows:

  • Cab cause anxiety, fatigue or lack of energy, drowsiness or insomnia, diarrhea, indigestion, among others specified as side effects. 
  • As with other antidepressants, taking fluoxetine increases the chance of suicidal thoughts and behavior.
  • Taking fluoxetine can cause drowsiness and impair your judgment or affect your driving abilities. 
  • Interaction with other drugs or overdosage can result in serotonin syndrome (includes symptoms such as agitation, hallucinations, coma, and delirium), a higher fast rate, feeling dizzy, flushed, shaky and muscle rigidity. 
  • Another syndrome caused by interaction with other drugs or substances is neuroleptic malignant syndrome. Symptoms for this syndrome include high body temperature, muscle rigidity, and psychological disturbances. 
  • Increases the risk of bleeding, especially if it is used with other drugs that also may increase bleeding. 
  • It can precipitate manic episodes if the person taking fluoxetine has undiagnosed bipolar disorder.
  •  May cause withdrawal symptoms if medication intake is stopped suddenly. 

Antidepressants: Suicidal Risk

Some studies have shown that taking antidepressants is associated with a higher risk of suicidal behavior (suicidal thinking or attempts) when compared to placebo drugs.

This risk has been associated with age in the case in children, adolescents, and adults with major depressive disorder (MDD) or related psychiatric disorders. 

One study conducted by the Centre for Suicide Research in Oxford, England attempted to identify which antidepressant drugs were more closely related to suicides or suicide attempts using coroner reports and hospital admissions from six hospitals across the United Kingdom and Wales (between 2000 and 2006). 

They found that Tricyclic antidepressants or TCAs had the highest toxicity and rate of fatality compared to other classes of antidepressants.

Additionally from the SSRIs group, Citalopram indicated to be the one with the highest toxicity and fatality rates. 

Besides being a treatment often used for depression, it can also be prescribed for the treatment of other major psychiatric disorders such as Obsessive-compulsive disorder (ODD), Panic disorder, premenstrual dysphoric syndrome (PMDD), anxiety disorders, post-traumatic stress disorder (PTSD) and eating disorders. 

People under antidepressant medication should always be monitored and observed closely to help reduce or prevent suicidal behavior.  

Why is this blog post about Prozac Dosage important?

This blog about Prozac Dosage is important because it helps understand what Prozac is, how it works, side effects, recommendations and precautions, overdose symptoms and course of action and benefits, and negative aspects of taking the medicine.

This will inform you about Prozac if you are considering taking or have started recently.

Please feel free to comment on Prozac dosage the comments section down below!

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